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• 51. [Article] Home range and habitat use of pileated woodpeckers, western Oregon

  Home range and habitat use by pileated woodpeckers (Dryocopus pileatus) were studied in the Coast Ranges of western Oregon. Radio-telemetry was used to determine home ranges of 11 woodpeckers and habitat ...

  Citation × Citation Citation Abstract Copy Title: Home range and habitat use of pileated woodpeckers, western Oregon Author: Mellen, Teresa Kim Home range and habitat use by pileated woodpeckers (Dryocopus pileatus) were studied in the Coast Ranges of western Oregon. Radio-telemetry was used to determine home ranges of 11 woodpeckers and habitat use of 14 woodpeckers after young had fledged during summers from 1982 to 1985. Home range size for individual bird averaged 480 ha; home ranges for pairs of birds were larger. Home ranges were larger than those reported in other studies. The larger home range sizes effectively reduce minimum snag densities calculated with formulas based on densities of birds. There was some overlap (11-160 ha) between adjacent home ranges. Pileated woodpeckers preferred forest habitat classes older than 40 years of age and deciduous riparian habitats for foraging and other diurnal activities. Nesting and roosting occurred in forest stands older than 70 years of age. The amount of foraging habitat within the home ranges averaged 306 ha; the amount of nesting and roosting habitat averaged 200 ha. Because pileated woodpeckers use immature forest stands for foraging they may not be a good "indicator" species for mature forest habitats. Characteristics of 15 nest and 13 roost trees (live and dead) and sites were measured from 1983 to 1986; characteristics were compared to those from other studies. Mean dbh differed significantly (P<0.05) between nest trees (68.9 cm) and roost trees (118.2cm). Trees used for nesting and roosting were taller than 11.5 m. A typical nest or roost tree had a broken top and retained most of the bark. Forest characteristics within a 0.3 ha circular plot at nest and roost sites were highly variable between sites. Discriminant analysis did not reveal a significant (P<0.05) difference between nest and roost sites found within 70- to 100-year-old stands and 100- to 200-year old stands. Mean dbh of nest trees was smaller, mean height of nest trees (26.5 m) was intermediate, and mean height of nest cavities (20 m) was higher than those reported from most other studies. Measured forest characteristics at nest sites were very different between studies because of differences in forests in terms of species composition, site productivity, climate and amount of disturbance. Findings were consistent with a previously recommended "minimum" dbh for pileated woodpecker nest trees of 63.5 cm (with bark). However, provision of nest trees with average characteristics would enhance management schemes which are directed toward minumum population numbers and a minimum amount of reserved habitat. Title: Home range and habitat use of pileated woodpeckers, western Oregon Author: Mellen, Teresa Kim Home range and habitat use by pileated woodpeckers (Dryocopus pileatus) were studied in the Coast Ranges of western Oregon. Radio-telemetry was used to determine home ranges of 11 woodpeckers and habitat use of 14 woodpeckers after young had fledged during summers from 1982 to 1985. Home range size for individual bird averaged 480 ha; home ranges for pairs of birds were larger. Home ranges were larger than those reported in other studies. The larger home range sizes effectively reduce minimum snag densities calculated with formulas based on densities of birds. There was some overlap (11-160 ha) between adjacent home ranges. Pileated woodpeckers preferred forest habitat classes older than 40 years of age and deciduous riparian habitats for foraging and other diurnal activities. Nesting and roosting occurred in forest stands older than 70 years of age. The amount of foraging habitat within the home ranges averaged 306 ha; the amount of nesting and roosting habitat averaged 200 ha. Because pileated woodpeckers use immature forest stands for foraging they may not be a good "indicator" species for mature forest habitats. Characteristics of 15 nest and 13 roost trees (live and dead) and sites were measured from 1983 to 1986; characteristics were compared to those from other studies. Mean dbh differed significantly (P<0.05) between nest trees (68.9 cm) and roost trees (118.2cm). Trees used for nesting and roosting were taller than 11.5 m. A typical nest or roost tree had a broken top and retained most of the bark. Forest characteristics within a 0.3 ha circular plot at nest and roost sites were highly variable between sites. Discriminant analysis did not reveal a significant (P<0.05) difference between nest and roost sites found within 70- to 100-year-old stands and 100- to 200-year old stands. Mean dbh of nest trees was smaller, mean height of nest trees (26.5 m) was intermediate, and mean height of nest cavities (20 m) was higher than those reported from most other studies. Measured forest characteristics at nest sites were very different between studies because of differences in forests in terms of species composition, site productivity, climate and amount of disturbance. Findings were consistent with a previously recommended "minimum" dbh for pileated woodpecker nest trees of 63.5 cm (with bark). However, provision of nest trees with average characteristics would enhance management schemes which are directed toward minumum population numbers and a minimum amount of reserved habitat. Close

• 52. [Article] Summer-time use of west coast US National Marine Sanctuaries by migrating sooty shearwaters (Puffinus griseus)

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier ...

  Citation × Citation Citation Abstract Copy Title: Summer-time use of west coast US National Marine Sanctuaries by migrating sooty shearwaters (Puffinus griseus) Author: MacLeod, Catriona, Suryan, Robert M., Harvey, James T., Hyrenbach, K. David, Adams, Josh To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Title: Summer-time use of west coast US National Marine Sanctuaries by migrating sooty shearwaters (Puffinus griseus) Author: MacLeod, Catriona, Suryan, Robert M., Harvey, James T., Hyrenbach, K. David, Adams, Josh To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Close

• 53. [Article] Effects of grass seed agriculture on aquatic invertebrate communities in seasonal wetlands of the southern Willamette Valley, Oregon

  An estimated 99% of native wet prairie has been lost in the Willamette Valley, Oregon, but a large number of seasonal wetlands remain on private lands dedicated to grass seed production within the historical ...

  Citation × Citation Citation Abstract Copy Title: Effects of grass seed agriculture on aquatic invertebrate communities in seasonal wetlands of the southern Willamette Valley, Oregon Author: Wyss, Lance A. An estimated 99% of native wet prairie has been lost in the Willamette Valley, Oregon, but a large number of seasonal wetlands remain on private lands dedicated to grass seed production within the historical wet prairie landscape. Because agriculture is known to alter physical and chemical wetland conditions, I investigated if aquatic invertebrate communities differed among annual grass seed farmed wetlands, perennial grass seed farmed wetlands, and native wet prairie. I sampled 30 southern Willamette Valley wetlands (n = 10 in each land use category) in spring of 2009 and resampled 28 in spring of 2010 that are hydrogeomorphically classified as Flats. Invertebrate community composition in native wet prairie differed from farmed wetlands (A-stats = 0.37, P < 0.001). Specifically, taxa richness (26.2 ± 1.2 in 2009 and 27.4 ± 1.0 in 2010) and diversity (3.0 ± 0.1 in 2009 and 3.1 ± 0.1 in 2010) were higher. From Indicator Species Analysis, taxa representative of wet prairie included a flightless beetle (Apteraliplus parvulus), a cladoceran (Dumontia oregonensis), an isopod (Caecidotea sp.), Calanoida copepods, and Lymnaeidae snails. Invertebrate density (individuals/m²) did not differ among land-use groups, but biomass (mg/m²) in perennial grass wetlands was greater than annual grass wetlands both years. Biomass in perennial grass farmed wetlands was also higher than native wet prairie in 2009 and similar in 2010. Wetland invertebrate composition was strongly associated with reduced vegetation cover and increases in water turbidity and conductivity with farmed sites having lower cover and higher turbidity and conductivity. These findings suggest grass seed farming practices such as soil tillage and field leveling have affects on invertebrate communities by lowering diversity and richness and altering community composition. However, farmed seasonal wetlands still provide habitat for aquatic invertebrates, contribute to the region's biodiversity, and are substantial food resources for wildlife. This grass seed agricultural landscape is an important seasonal wetland habitat and needs to be incorporated into regional conservation plans. Title: Effects of grass seed agriculture on aquatic invertebrate communities in seasonal wetlands of the southern Willamette Valley, Oregon Author: Wyss, Lance A. An estimated 99% of native wet prairie has been lost in the Willamette Valley, Oregon, but a large number of seasonal wetlands remain on private lands dedicated to grass seed production within the historical wet prairie landscape. Because agriculture is known to alter physical and chemical wetland conditions, I investigated if aquatic invertebrate communities differed among annual grass seed farmed wetlands, perennial grass seed farmed wetlands, and native wet prairie. I sampled 30 southern Willamette Valley wetlands (n = 10 in each land use category) in spring of 2009 and resampled 28 in spring of 2010 that are hydrogeomorphically classified as Flats. Invertebrate community composition in native wet prairie differed from farmed wetlands (A-stats = 0.37, P < 0.001). Specifically, taxa richness (26.2 ± 1.2 in 2009 and 27.4 ± 1.0 in 2010) and diversity (3.0 ± 0.1 in 2009 and 3.1 ± 0.1 in 2010) were higher. From Indicator Species Analysis, taxa representative of wet prairie included a flightless beetle (Apteraliplus parvulus), a cladoceran (Dumontia oregonensis), an isopod (Caecidotea sp.), Calanoida copepods, and Lymnaeidae snails. Invertebrate density (individuals/m²) did not differ among land-use groups, but biomass (mg/m²) in perennial grass wetlands was greater than annual grass wetlands both years. Biomass in perennial grass farmed wetlands was also higher than native wet prairie in 2009 and similar in 2010. Wetland invertebrate composition was strongly associated with reduced vegetation cover and increases in water turbidity and conductivity with farmed sites having lower cover and higher turbidity and conductivity. These findings suggest grass seed farming practices such as soil tillage and field leveling have affects on invertebrate communities by lowering diversity and richness and altering community composition. However, farmed seasonal wetlands still provide habitat for aquatic invertebrates, contribute to the region's biodiversity, and are substantial food resources for wildlife. This grass seed agricultural landscape is an important seasonal wetland habitat and needs to be incorporated into regional conservation plans. Close

• 54. [Article] How Cities Can Increase Cycling Among Women An Evaluation of: Portland, OR, Washington D.C., and Vancouver B.C.

  56 pages

  Citation × Citation Citation Abstract Copy Title: How Cities Can Increase Cycling Among Women An Evaluation of: Portland, OR, Washington D.C., and Vancouver B.C. Author: Horan, Erin Year: 2016 56 pages Title: How Cities Can Increase Cycling Among Women An Evaluation of: Portland, OR, Washington D.C., and Vancouver B.C. Author: Horan, Erin Year: 2016 56 pages Close

• 55. [Article] Mapping conservation opportunity areas for the Intertwine's Regional Conservation Strategy

  Draft report from the Institute for Natural Resources, Portland State University

  Citation × Citation Citation Abstract Copy Title: Mapping conservation opportunity areas for the Intertwine's Regional Conservation Strategy Author: Kagan, James S., Burcsu, Theresa Draft report from the Institute for Natural Resources, Portland State University Title: Mapping conservation opportunity areas for the Intertwine's Regional Conservation Strategy Author: Kagan, James S., Burcsu, Theresa Draft report from the Institute for Natural Resources, Portland State University Close

• 56. [Article] Forest macro-arthropods as potential indicators of ecosystem conditions in Western Idaho : an analysis of community composition, biological diversity, and community structure

  Adaptive ecosystem management is a new paradigm for managing federal forests which requires regular monitoring of ecosystem function and diversity to measure the effects of management. Managers need new ...

  Citation × Citation Citation Abstract Copy Title: Forest macro-arthropods as potential indicators of ecosystem conditions in Western Idaho : an analysis of community composition, biological diversity, and community structure Author: Ruby, Margaret E. Adaptive ecosystem management is a new paradigm for managing federal forests which requires regular monitoring of ecosystem function and diversity to measure the effects of management. Managers need new strategies and tools to help them assess their progress in maintaining healthy, productive and biologically diverse forests. Biomonitoring of select forest macro-arthropod species can provide useful information on the effects of management on forest biodiversity and ecosystem function. The purpose of this study was threefold: (1) to inventory the macro-arthropod community and important environmental variables in the Bear Creek and Indian Creek study area within the Payette National Forest (PNF) in Western Idaho; (2) to compare measures of community composition, diversity, and structure in forest macro-arthropod communities between patches of different sizes and treatment; and (3) to assist PNF managers in their ecosystem management efforts by providing principles to guide the use of macro-arthropods as indicators of changing forest conditions. Transects with pitfall traps were used to collect macro-arthropods at 22 sites in the Bear Creek and Indian Creek study area during the summer of 1994. Five forest patch types in Abies grandis habitat types were sampled. Intact forest patches of 100 or more hectares, and large patches of 50-100 hectares, ranged in age between 50 and 250 years old with multistoried structure. Small patches up to 10 hectares were remnants or fragments of formerly intact forest isolated by logging. A plantation patch was 15 years old with patchy understory and forb cover. Clearcut patches had little or no overstory, and variable understory, and forb layers. At each transect, soil samples were collected and six environmental descriptor variables were analyzed according to patch treatment and patch size. These site descriptors were: basal area (ft²/acre); percent canopy cover for the overstory, understory; and forb layers; litter depth (cm), and percent soil moisture content. Differences detected using an ANOVA and T-tests are discussed in the Results section. Arthropod community composition, diversity, and structure were described according to relative abundance, and four measures of diversity. They were also described by membership in seventeen orders and/or super-families; ten functional groups; two disperser classes (long or short distance); and three species indicator classes. A total of 5455 macro-arthropod individuals, representing 17 orders and/or super-families and 219 species were collected in the Bear Creek and Indian Creek study area. While macro-arthropod fauna relative abundance did not vary significantly by treatment (ANOVA p<0.3), it did vary significantly by patch size (ANOVA p<0.03). Fauna relative abundance was 35% greater in clearcut patches than in large patches (T-test p<0.09). Fauna relative abundance in small patches was twice that of intact (T-test p<0.03) and large (T-test p<0.02) patches. Taxonomic diversity (number of genera/taxa) of beetle, ant, and bug taxa differed significantly according to treatment type(each ANOVA p<0.05). For the top four taxa (beetles, ants, spiders, and bugs), taxonomic diversity was highest in the plantation and clearcut patches. Ants and bugs had their highest taxonomic diversity in the plantation patch (separate T-tests p<0.05) while the taxonomic diversity of beetles was highest in clear-cut patches (T-test p<0.05). Beetle and ant taxonomic diversity varied significantly by patch size (each ANOVA p<0.05). For beetles and bugs, small patches were twice as diverse as intact patches (separate T-tests p<0.04) and 1.5 times that of large patches. Ant diversity was similarly distributed amongst the patch sizes, with significant differences between small and intact and between small and large patches (separate T-tests p<0.05). Of the four species diversity measures employed, only two, [alpha] and JK1 (both measures of richness), were found to vary significantly by patch treatment and size. Evenness (E) and the Shannon Diversity Index (H') failed to detect differences in the majority of tests. Fauna [alpha] and JK1 differed significantly by treatment type (each ANOVA p<0.05). Richness in clearcut patches was nearly twice in intact and large patches, followed by plantation and large patches. Fauna [alpha] and JKl also differed significantly by patch size (each ANOVA p <0.001), with small patch fauna twice as rich as that in large and intact patches (separate T-tests p <0.01). Of the top four functional groups, predators were the most abundant and had the highest taxonomic diversity (number of genera/functional group), followed by herbivores, fungivores and parasites. Predators and herbivores showed increasing taxonomic diversity with decreasing patch size, from intact to large to small (ANOVA p< 0.05). Similarly, predators and herbivores exhibited increasing taxonomic diversity with increasing levels of management: from intact and large to plantation and clear-cuts (ANOVA p< 0.05). Predators and herbivores were most numerous in the managed and small patches. Fungivore taxonomic diversity was also highest in the small and managed patches, though neither patch size nor treatment differences were significant (ANOVA p<0.85). Parasite taxonomic diversity differed by patch size with highest generic diversity in the small patches (ANOVA p<0.l) and by treatment type with generic diversity highest in plantations and clearcuts followed in order by large and intact patches (ANOVA p<0.l). Twice as many genera were long distance dispersers as were short distance dispersers. Relative abundance of long distance dispersers varied significantly by patch treatment and patch size (each ANOVA p<0.0l). Long distance dispersers were most numerous in clear-cut patches, followed in order by plantation, small, large, and intact patches. Relative abundance of short distance dispersers was not significantly different between treatment types (ANOVA p<0.20) but was significantly different between patch sizes (ANOVA p<0.0l). Short distance dispersers were most numerous in small patches followed by plantation, large, and intact and least numerous in clearcut patches. An indicator species analysis of 121 Bear Creek and Indian Creek genera (Dufrene and Legendre 1997), revealed sub-groups of species with 75 to 100 percent "perfect indication" or affiliation for specific patch types. When intact and large patches were pooled and analyzed against all treated patches (plantation and clearcut patches), a list of 36 genera with 75 to 100 percent "perfect affiliation" for intact or large patches was produced (MRPP p<0.05). Small patches had 42 indicators with 75 to 100 percent "perfect indication" when compared with the pooled intact and large patches (MRPP p<0.l). Conclusions Macro-arthropod community composition, diversity and structure did vary, usually significantly, by patch treatment and size. Useful measures of generic diversity include richness estimators [alpha], [beta], and JK1. Examination of taxonomic diversity was also useful, especially for the more mobile arthropods. Pitfall traps provided copious data on the structure of the community in regards to predators and herbivores. Pitfalls, however, did not provide much information about the status of fungivores and parasites in the various different patches. Another trapping method such as the berlaise funnel, would likely provide more information about those functional groups which are likely operating at a finer scale of resolution than that tested by the pitfall trap. Employing both methods would provide a much better assessment of the community of arthropods living on the forest floor. The indicator species analysis program also provided very useful lists of species which are affiliated with particular patch conditions. Taken together, these measures could be adopted for use by forest managers to allow them to assess and monitor the effects of a management regime on the structure and composition of macro-arthropod communities as part of a comprehensive adaptive management plan. Title: Forest macro-arthropods as potential indicators of ecosystem conditions in Western Idaho : an analysis of community composition, biological diversity, and community structure Author: Ruby, Margaret E. Adaptive ecosystem management is a new paradigm for managing federal forests which requires regular monitoring of ecosystem function and diversity to measure the effects of management. Managers need new strategies and tools to help them assess their progress in maintaining healthy, productive and biologically diverse forests. Biomonitoring of select forest macro-arthropod species can provide useful information on the effects of management on forest biodiversity and ecosystem function. The purpose of this study was threefold: (1) to inventory the macro-arthropod community and important environmental variables in the Bear Creek and Indian Creek study area within the Payette National Forest (PNF) in Western Idaho; (2) to compare measures of community composition, diversity, and structure in forest macro-arthropod communities between patches of different sizes and treatment; and (3) to assist PNF managers in their ecosystem management efforts by providing principles to guide the use of macro-arthropods as indicators of changing forest conditions. Transects with pitfall traps were used to collect macro-arthropods at 22 sites in the Bear Creek and Indian Creek study area during the summer of 1994. Five forest patch types in Abies grandis habitat types were sampled. Intact forest patches of 100 or more hectares, and large patches of 50-100 hectares, ranged in age between 50 and 250 years old with multistoried structure. Small patches up to 10 hectares were remnants or fragments of formerly intact forest isolated by logging. A plantation patch was 15 years old with patchy understory and forb cover. Clearcut patches had little or no overstory, and variable understory, and forb layers. At each transect, soil samples were collected and six environmental descriptor variables were analyzed according to patch treatment and patch size. These site descriptors were: basal area (ft²/acre); percent canopy cover for the overstory, understory; and forb layers; litter depth (cm), and percent soil moisture content. Differences detected using an ANOVA and T-tests are discussed in the Results section. Arthropod community composition, diversity, and structure were described according to relative abundance, and four measures of diversity. They were also described by membership in seventeen orders and/or super-families; ten functional groups; two disperser classes (long or short distance); and three species indicator classes. A total of 5455 macro-arthropod individuals, representing 17 orders and/or super-families and 219 species were collected in the Bear Creek and Indian Creek study area. While macro-arthropod fauna relative abundance did not vary significantly by treatment (ANOVA p<0.3), it did vary significantly by patch size (ANOVA p<0.03). Fauna relative abundance was 35% greater in clearcut patches than in large patches (T-test p<0.09). Fauna relative abundance in small patches was twice that of intact (T-test p<0.03) and large (T-test p<0.02) patches. Taxonomic diversity (number of genera/taxa) of beetle, ant, and bug taxa differed significantly according to treatment type(each ANOVA p<0.05). For the top four taxa (beetles, ants, spiders, and bugs), taxonomic diversity was highest in the plantation and clearcut patches. Ants and bugs had their highest taxonomic diversity in the plantation patch (separate T-tests p<0.05) while the taxonomic diversity of beetles was highest in clear-cut patches (T-test p<0.05). Beetle and ant taxonomic diversity varied significantly by patch size (each ANOVA p<0.05). For beetles and bugs, small patches were twice as diverse as intact patches (separate T-tests p<0.04) and 1.5 times that of large patches. Ant diversity was similarly distributed amongst the patch sizes, with significant differences between small and intact and between small and large patches (separate T-tests p<0.05). Of the four species diversity measures employed, only two, [alpha] and JK1 (both measures of richness), were found to vary significantly by patch treatment and size. Evenness (E) and the Shannon Diversity Index (H') failed to detect differences in the majority of tests. Fauna [alpha] and JK1 differed significantly by treatment type (each ANOVA p<0.05). Richness in clearcut patches was nearly twice in intact and large patches, followed by plantation and large patches. Fauna [alpha] and JKl also differed significantly by patch size (each ANOVA p <0.001), with small patch fauna twice as rich as that in large and intact patches (separate T-tests p <0.01). Of the top four functional groups, predators were the most abundant and had the highest taxonomic diversity (number of genera/functional group), followed by herbivores, fungivores and parasites. Predators and herbivores showed increasing taxonomic diversity with decreasing patch size, from intact to large to small (ANOVA p< 0.05). Similarly, predators and herbivores exhibited increasing taxonomic diversity with increasing levels of management: from intact and large to plantation and clear-cuts (ANOVA p< 0.05). Predators and herbivores were most numerous in the managed and small patches. Fungivore taxonomic diversity was also highest in the small and managed patches, though neither patch size nor treatment differences were significant (ANOVA p<0.85). Parasite taxonomic diversity differed by patch size with highest generic diversity in the small patches (ANOVA p<0.l) and by treatment type with generic diversity highest in plantations and clearcuts followed in order by large and intact patches (ANOVA p<0.l). Twice as many genera were long distance dispersers as were short distance dispersers. Relative abundance of long distance dispersers varied significantly by patch treatment and patch size (each ANOVA p<0.0l). Long distance dispersers were most numerous in clear-cut patches, followed in order by plantation, small, large, and intact patches. Relative abundance of short distance dispersers was not significantly different between treatment types (ANOVA p<0.20) but was significantly different between patch sizes (ANOVA p<0.0l). Short distance dispersers were most numerous in small patches followed by plantation, large, and intact and least numerous in clearcut patches. An indicator species analysis of 121 Bear Creek and Indian Creek genera (Dufrene and Legendre 1997), revealed sub-groups of species with 75 to 100 percent "perfect indication" or affiliation for specific patch types. When intact and large patches were pooled and analyzed against all treated patches (plantation and clearcut patches), a list of 36 genera with 75 to 100 percent "perfect affiliation" for intact or large patches was produced (MRPP p<0.05). Small patches had 42 indicators with 75 to 100 percent "perfect indication" when compared with the pooled intact and large patches (MRPP p<0.l). Conclusions Macro-arthropod community composition, diversity and structure did vary, usually significantly, by patch treatment and size. Useful measures of generic diversity include richness estimators [alpha], [beta], and JK1. Examination of taxonomic diversity was also useful, especially for the more mobile arthropods. Pitfall traps provided copious data on the structure of the community in regards to predators and herbivores. Pitfalls, however, did not provide much information about the status of fungivores and parasites in the various different patches. Another trapping method such as the berlaise funnel, would likely provide more information about those functional groups which are likely operating at a finer scale of resolution than that tested by the pitfall trap. Employing both methods would provide a much better assessment of the community of arthropods living on the forest floor. The indicator species analysis program also provided very useful lists of species which are affiliated with particular patch conditions. Taken together, these measures could be adopted for use by forest managers to allow them to assess and monitor the effects of a management regime on the structure and composition of macro-arthropod communities as part of a comprehensive adaptive management plan. Close

• 57. [Article] Comparing vegetation and soils of remnant and restored prairie wetlands in the northern Willamette Valley

  Native prairies of the Willamette Valley are considered among the rarest of Oregon's ecosystems (Clark and Wilson, 2001). As a result of agriculture conversion, urban development and cessation of native ...

  Citation × Citation Citation Abstract Copy Title: Comparing vegetation and soils of remnant and restored prairie wetlands in the northern Willamette Valley Author: Taylor, Sara M. Native prairies of the Willamette Valley are considered among the rarest of Oregon's ecosystems (Clark and Wilson, 2001). As a result of agriculture conversion, urban development and cessation of native burning, Willamette Valley prairies have become highly fragmented and invaded by non-native species, leaving little room for native plant diversity. Even though wetland prairie conservation and restoration has been a priority for many government agencies there is a need for research on what restoration techniques and management are necessary for increasing native species richness and abundance in remnant and restored wet prairie sites. In this research project, two studies were conducted. In the first study, data were collected on species presence and abundance from three 100m² randomized plots within three remnant wet prairies (Green Mountain, Gotter Prairie South, Knez) and three restored wet prairies (Hutchinson, Gotter Prairie North, Lovejoy) to answer the following research question, 'Are there differences between remnant and restored prairie plant communities with respect to the diversity and abundance of native species?' Analysis of variance and multivariate ordination techniques were used to assess the ecological differences between uncultivated, minimally-managed remnant wet prairies and newly-restored, highly managed wet prairies. Data on soils collected from agricultural sites (Westbrook, Zurcher, Gotter Prairie Ag), as well as the remnant and restored wet prairies mentioned above, were also used to compare soil quality and processes with the remnant and restored wetlands. Restored wet prairie had 23% higher native species cover than remnant prairie (p-value=0.089, N=6). Remnant and restored sites did not differ in native species richness (p-value=0.949, N=6). The relatively high per cent cover of native species at restored sites, (significant at the 10% level), suggests that land managers have successfully restored agricultural properties with an abundance of native species. The lack of significant difference in native species richness between remnant and restored sites also suggests that land managers have also been able to restore native plant diversity into former agricultural properties equivalent to some of the best intact remnant prairies within the Northern Willamette Valley in a short period of time (8 years or less). However, a non-metric scaling (NMS) ordination of the species matrix separated the remnant sites from the restored sites, suggesting that community composition distinguishes restored sites from remnants. The NMS results, which include environmental data in the analysis, also suggest that there is a positive correlation of percent soil moisture and percent soil organic matter associated with the remnant prairies and a positive correlation of management practices such as yearly chemical use, mowing, and clean crops, associated with the restored prairies. The location of Gotter Prairie North restoration within the ordination, between the remnant and restored sites, suggests an intermediate plant composition and soil quality. This could be attributed to intensive weed suppression and soil organic matter build up over time (8 years) in comparison to younger restored sites (3 and 4 years). Indicator species analysis identified many species with high indicator values (IVs) in the remnant prairies; Holcus lanatus, Deschampsia cespitosa, Carex densa and Phalaris arundinacea being the highest. The use of fire as a management tool produced only one species with a high IV (Camassia quamash). In the second study, three seeding treatments (Grass first, Grass and Forb together, Forb first) were compared within a 4 hectare experimental wet prairie unit to answer the research question „Which of the three seeding treatments used leads to the highest native species abundance and species richness?‟ Results from an analysis of variance indicated significant differences between treatments in native species richness for 2009 and 2010 (p-values=0.002 & 0.004 respectively) at the 5% level and native species abundance in 2010 only (p-value=0.099) at the 10% level. The Grass and Forb and Forb first treatments were highest in native species richness for 2009 and 2010, whereas the Grass and Forb and Grass first treatments were highest in native species abundance in 2010. A NMS ordination suggests that Juncus tenuis is one of the dominant species, in all seeding treatments, after one year of growth. Title: Comparing vegetation and soils of remnant and restored prairie wetlands in the northern Willamette Valley Author: Taylor, Sara M. Native prairies of the Willamette Valley are considered among the rarest of Oregon's ecosystems (Clark and Wilson, 2001). As a result of agriculture conversion, urban development and cessation of native burning, Willamette Valley prairies have become highly fragmented and invaded by non-native species, leaving little room for native plant diversity. Even though wetland prairie conservation and restoration has been a priority for many government agencies there is a need for research on what restoration techniques and management are necessary for increasing native species richness and abundance in remnant and restored wet prairie sites. In this research project, two studies were conducted. In the first study, data were collected on species presence and abundance from three 100m² randomized plots within three remnant wet prairies (Green Mountain, Gotter Prairie South, Knez) and three restored wet prairies (Hutchinson, Gotter Prairie North, Lovejoy) to answer the following research question, 'Are there differences between remnant and restored prairie plant communities with respect to the diversity and abundance of native species?' Analysis of variance and multivariate ordination techniques were used to assess the ecological differences between uncultivated, minimally-managed remnant wet prairies and newly-restored, highly managed wet prairies. Data on soils collected from agricultural sites (Westbrook, Zurcher, Gotter Prairie Ag), as well as the remnant and restored wet prairies mentioned above, were also used to compare soil quality and processes with the remnant and restored wetlands. Restored wet prairie had 23% higher native species cover than remnant prairie (p-value=0.089, N=6). Remnant and restored sites did not differ in native species richness (p-value=0.949, N=6). The relatively high per cent cover of native species at restored sites, (significant at the 10% level), suggests that land managers have successfully restored agricultural properties with an abundance of native species. The lack of significant difference in native species richness between remnant and restored sites also suggests that land managers have also been able to restore native plant diversity into former agricultural properties equivalent to some of the best intact remnant prairies within the Northern Willamette Valley in a short period of time (8 years or less). However, a non-metric scaling (NMS) ordination of the species matrix separated the remnant sites from the restored sites, suggesting that community composition distinguishes restored sites from remnants. The NMS results, which include environmental data in the analysis, also suggest that there is a positive correlation of percent soil moisture and percent soil organic matter associated with the remnant prairies and a positive correlation of management practices such as yearly chemical use, mowing, and clean crops, associated with the restored prairies. The location of Gotter Prairie North restoration within the ordination, between the remnant and restored sites, suggests an intermediate plant composition and soil quality. This could be attributed to intensive weed suppression and soil organic matter build up over time (8 years) in comparison to younger restored sites (3 and 4 years). Indicator species analysis identified many species with high indicator values (IVs) in the remnant prairies; Holcus lanatus, Deschampsia cespitosa, Carex densa and Phalaris arundinacea being the highest. The use of fire as a management tool produced only one species with a high IV (Camassia quamash). In the second study, three seeding treatments (Grass first, Grass and Forb together, Forb first) were compared within a 4 hectare experimental wet prairie unit to answer the research question „Which of the three seeding treatments used leads to the highest native species abundance and species richness?‟ Results from an analysis of variance indicated significant differences between treatments in native species richness for 2009 and 2010 (p-values=0.002 & 0.004 respectively) at the 5% level and native species abundance in 2010 only (p-value=0.099) at the 10% level. The Grass and Forb and Forb first treatments were highest in native species richness for 2009 and 2010, whereas the Grass and Forb and Grass first treatments were highest in native species abundance in 2010. A NMS ordination suggests that Juncus tenuis is one of the dominant species, in all seeding treatments, after one year of growth. Close

• 58. [Article] Using Oregon trawl logbooks to study spatial and temporal characteristics of commercial groundfish species associations

  Species associations of fifteen major commercial groundfish species in the northeastern Pacific ocean and their spatial and temporal characteristics were studied using Oregon bottom trawl logbook data, ...

  Citation × Citation Citation Abstract Copy Title: Using Oregon trawl logbooks to study spatial and temporal characteristics of commercial groundfish species associations Author: Lee, Yong Woo Species associations of fifteen major commercial groundfish species in the northeastern Pacific ocean and their spatial and temporal characteristics were studied using Oregon bottom trawl logbook data, 1987 to 1993. Screening procedures were used to remove questionable data from the original logbook files, which resulted in the exclusion of information from 46% of the total available tows. Two multivariate methods, detrended correspondence analysis (DCA) and Ward's method of hierarchical cluster analysis were used to derive the association patterns of species and species groups. A general linear model that was developed for the primary DCA axis suggested that the species associations are strongly correlated with depth, but minimally correlated with the other environmental variables that were examined (latitude, season, and year). The weak correlations between DCA axis 1 and the temporal variables indicate that species associations in the study region are fairly persistent over time. The same multivariate techniques were used to examine possible sampling effects due to changes in the participating trawl vessels that contributed logbook information. Depth and latitudinal distributions of species occurrence in the logbook were similar to distributions derived from National Marine Fishery Service triennial bottom trawl survey. However, the analysis also showed that the depth coverage by the survey is not broad enough to accurately characterize associations among species that are currently subject to commercial fishing activity. Title: Using Oregon trawl logbooks to study spatial and temporal characteristics of commercial groundfish species associations Author: Lee, Yong Woo Species associations of fifteen major commercial groundfish species in the northeastern Pacific ocean and their spatial and temporal characteristics were studied using Oregon bottom trawl logbook data, 1987 to 1993. Screening procedures were used to remove questionable data from the original logbook files, which resulted in the exclusion of information from 46% of the total available tows. Two multivariate methods, detrended correspondence analysis (DCA) and Ward's method of hierarchical cluster analysis were used to derive the association patterns of species and species groups. A general linear model that was developed for the primary DCA axis suggested that the species associations are strongly correlated with depth, but minimally correlated with the other environmental variables that were examined (latitude, season, and year). The weak correlations between DCA axis 1 and the temporal variables indicate that species associations in the study region are fairly persistent over time. The same multivariate techniques were used to examine possible sampling effects due to changes in the participating trawl vessels that contributed logbook information. Depth and latitudinal distributions of species occurrence in the logbook were similar to distributions derived from National Marine Fishery Service triennial bottom trawl survey. However, the analysis also showed that the depth coverage by the survey is not broad enough to accurately characterize associations among species that are currently subject to commercial fishing activity. Close

• 59. [Article] Life history of Philophthalmus megalurus (Cort, 1914) in western Oregon

  The specific identification of a megalurous cercaria found in the snail Oxytrema plicifera was accomplished by completing the life cycle in the laboratory. This species is compared with the eastern Philophthalmus ...

  Citation × Citation Citation Abstract Copy Title: Life history of Philophthalmus megalurus (Cort, 1914) in western Oregon Author: McMillan, Toni Anne Year: 1971 The specific identification of a megalurous cercaria found in the snail Oxytrema plicifera was accomplished by completing the life cycle in the laboratory. This species is compared with the eastern Philophthalmus megalurus and P. gralli with which it was once confused. The eggs, miracidia, and rediae of the Oregon species were found to be similar to those of the above species. The body and organ sizes and sucker ratios for the cercariae and adult stages obviously indicate that the Oregon species is Philophthalmus megalurus. Title: Life history of Philophthalmus megalurus (Cort, 1914) in western Oregon Author: McMillan, Toni Anne Year: 1971 The specific identification of a megalurous cercaria found in the snail Oxytrema plicifera was accomplished by completing the life cycle in the laboratory. This species is compared with the eastern Philophthalmus megalurus and P. gralli with which it was once confused. The eggs, miracidia, and rediae of the Oregon species were found to be similar to those of the above species. The body and organ sizes and sucker ratios for the cercariae and adult stages obviously indicate that the Oregon species is Philophthalmus megalurus. Close

• 60. [Article] Plant and amphibian assemblages in zero-order basins in the Oregon Coast Range

  We have a poor understanding of the biotic communities in zero-order basins, drainages extending from ridgelines to the initiation of first-order streams. This study describes baseline plant and amphibian ...

  Citation × Citation Citation Abstract Copy Title: Plant and amphibian assemblages in zero-order basins in the Oregon Coast Range Author: Sheridan, Chris D. We have a poor understanding of the biotic communities in zero-order basins, drainages extending from ridgelines to the initiation of first-order streams. This study describes baseline plant and amphibian composition in unmanaged zero-order basins in the Oregon Coast Range. Specifically, I studied: i) the spatial distribution and diversity of species, including riparian-associates; and ii) the dominant environmental, spatial and geomorphic gradients in species composition The results of this research have implications for riparian management in steep, forested landscapes in the Pacific Northwest. The composition of tree and shrub layers in zero-order basins was more similar to upland areas than to larger-order riparian areas. Douglas-fir, western hemlock, and western red cedar had highest basal areas; bigleaf maple had highest hardwood density. Convergent areas (areas collecting surface flow) had significantly lower relative densities than surrounding slopes. I identified 138 forest floor herb, shrub, and seedling tree species in zero-order basins. Gradient analysis and empirical modeling suggested that the composition of forest floor plant assemblages was associated with environmental parameters related to geomorphic position and overstory characteristics, such as distance from basin center, basin aspect and overstory relative density. Vegetation types, developed using classification, followed similar environmental patterns. Vegetation types were useful in clarifying environmental gradients acting on groups of plant species, and in delineating the lateral extent of geomorphic and fluvial influences. Riparian-associated vegetation types were mostly restricted to valley floors and lower slope areas. Geomorphic and lateral surfaces were drivers of environmental gradients in zero-order basins; plant species composition followed these geomorphic gradients. Surfaces close to basin center ("inner gorges"), including valley centers, splash zones, and lower slope areas, supported the highest plant species diversity and most distinct plant assemblages. The spatial distribution patterns of amphibian species and assemblages were characterized along longitudinal and lateral gradients, and relative to three geomorphic surfaces (valleys, headmost areas and slopes), and empirical species-habitat models were developed. I identified eight amphibian species in zero-order basins (865 total captures), and analyzed data for six. Headmost areas supported a distinctive upland amphibian assemblage, while valley floors had the highest riparian amphibian diversity. Captures of three riparian species were higher in valley surfaces, within S m of the center of zero-order basins, while captures of three upland species were highest in areas 2-5 m from center. Upland-associated species were captured two times farther from basin centers than riparian-associated species. The best predictors of amphibian captures in empirical models were geomorphic, stability/ disturbance, moisture and overstory parameters. Ordination and indicator species analysis facilitated characterization of amphibian species assemblages within geomorphic surface zones, and suggested spatial compression of habitats and species in zero-order basins, in comparison to broader spatial extents in larger basins. Plant and amphibian assemblages in unmanaged zero-order basins were most similar to each other in their lateral and geomorphic spatial patterning, including the importance of inner gorge areas for support of diverse communities. Plant species were strongly associated with geomorphic position parameters, while amphibians had stronger ties to discrete microhabitat elements such as moisture levels and large substrate. Amphibians appeared to have a more distinctive assemblage in headmost areas than plant species. Results suggest that assemblages of plants and amphibians in these basins are distinct from both larger-order riparian assemblages and from vegetation in surrounding hillslopes. Riparian management designs could take these spatial patterns and habitat associations into account to maintain the ecological integrity of headwater communities. The longitudinal and lateral extents of landscape areas managed to minimize risk to persistence of zero-order basin plant and amphibian assemblages would need to incorporate both fluvial and hillslope disturbance regimes, and microhabitat features associated with them. Title: Plant and amphibian assemblages in zero-order basins in the Oregon Coast Range Author: Sheridan, Chris D. We have a poor understanding of the biotic communities in zero-order basins, drainages extending from ridgelines to the initiation of first-order streams. This study describes baseline plant and amphibian composition in unmanaged zero-order basins in the Oregon Coast Range. Specifically, I studied: i) the spatial distribution and diversity of species, including riparian-associates; and ii) the dominant environmental, spatial and geomorphic gradients in species composition The results of this research have implications for riparian management in steep, forested landscapes in the Pacific Northwest. The composition of tree and shrub layers in zero-order basins was more similar to upland areas than to larger-order riparian areas. Douglas-fir, western hemlock, and western red cedar had highest basal areas; bigleaf maple had highest hardwood density. Convergent areas (areas collecting surface flow) had significantly lower relative densities than surrounding slopes. I identified 138 forest floor herb, shrub, and seedling tree species in zero-order basins. Gradient analysis and empirical modeling suggested that the composition of forest floor plant assemblages was associated with environmental parameters related to geomorphic position and overstory characteristics, such as distance from basin center, basin aspect and overstory relative density. Vegetation types, developed using classification, followed similar environmental patterns. Vegetation types were useful in clarifying environmental gradients acting on groups of plant species, and in delineating the lateral extent of geomorphic and fluvial influences. Riparian-associated vegetation types were mostly restricted to valley floors and lower slope areas. Geomorphic and lateral surfaces were drivers of environmental gradients in zero-order basins; plant species composition followed these geomorphic gradients. Surfaces close to basin center ("inner gorges"), including valley centers, splash zones, and lower slope areas, supported the highest plant species diversity and most distinct plant assemblages. The spatial distribution patterns of amphibian species and assemblages were characterized along longitudinal and lateral gradients, and relative to three geomorphic surfaces (valleys, headmost areas and slopes), and empirical species-habitat models were developed. I identified eight amphibian species in zero-order basins (865 total captures), and analyzed data for six. Headmost areas supported a distinctive upland amphibian assemblage, while valley floors had the highest riparian amphibian diversity. Captures of three riparian species were higher in valley surfaces, within S m of the center of zero-order basins, while captures of three upland species were highest in areas 2-5 m from center. Upland-associated species were captured two times farther from basin centers than riparian-associated species. The best predictors of amphibian captures in empirical models were geomorphic, stability/ disturbance, moisture and overstory parameters. Ordination and indicator species analysis facilitated characterization of amphibian species assemblages within geomorphic surface zones, and suggested spatial compression of habitats and species in zero-order basins, in comparison to broader spatial extents in larger basins. Plant and amphibian assemblages in unmanaged zero-order basins were most similar to each other in their lateral and geomorphic spatial patterning, including the importance of inner gorge areas for support of diverse communities. Plant species were strongly associated with geomorphic position parameters, while amphibians had stronger ties to discrete microhabitat elements such as moisture levels and large substrate. Amphibians appeared to have a more distinctive assemblage in headmost areas than plant species. Results suggest that assemblages of plants and amphibians in these basins are distinct from both larger-order riparian assemblages and from vegetation in surrounding hillslopes. Riparian management designs could take these spatial patterns and habitat associations into account to maintain the ecological integrity of headwater communities. The longitudinal and lateral extents of landscape areas managed to minimize risk to persistence of zero-order basin plant and amphibian assemblages would need to incorporate both fluvial and hillslope disturbance regimes, and microhabitat features associated with them. Close

• 61. [Article] Comparative Characterization of Two Nearshore Rocky Reef Areas: A high-use recreational fishing reef vs. an unfished reef

  This project has provided the ODFW Marine Habitat Project with a unique opportunity to make a comparative examination of the habitats and fish communities of a heavily fished reef off of Siletz Bay, and ...

  Citation × Citation Citation Abstract Copy Title: Comparative Characterization of Two Nearshore Rocky Reef Areas: A high-use recreational fishing reef vs. an unfished reef Author: Merems, Arlene, Appy, Marcus, Romsos, Chris, Weeks, Hal, Fox, David, Amend, Mark This project has provided the ODFW Marine Habitat Project with a unique opportunity to make a comparative examination of the habitats and fish communities of a heavily fished reef off of Siletz Bay, and a nearly unfished reef off Cape Perpetua. There are over 17,000 angler trips for groundfish out of Depoe Bay annually, many choosing to fish Siletz Reef. In addition, numerous whale watching and sightseeing charter vessels operate in the vicinity of the reef. Cape Perpetua Reef consists of isolated patches of rock, and is too far from Newport (the nearest port) to receive much fishing effort. This examination of the influences of fishing pressure in nearshore rocky habitat complements, and is embedded in, a broader effort to understand the distribution and character of Oregon’s nearshore rocky reefs, and the species that are dependent upon them for habitat. The ODFW Marine Habitat Project has spent the last eight years working in cooperation with scientists and other resource agencies to develop methods for classifying and mapping nearshore rocky reefs habitats off Oregon. Because nearshore reefs are in state waters, Oregon is responsible for managing these living resources and habitats to sustain their long-term use and productivity. To date, eight reefs have been surveyed and mapped with sidescan and/or multibeam bathymetry at a resolution indicative of fish habitat. ODFW has also been developing non-extractive fish survey techniques to describe fish-habitat associations and estimate fish abundance at the habitat and reef scale. The importance of habitat to reef species cannot be over-stated and is now widely accepted in the scientific community and is the focus of major research efforts in other Pacific coastal states. Better understanding of the degree to which harvest influences relative and absolute abundance, combined with species-habitat relationships, is essential for resource managers to exercise their stewardship responsibilities to protect 5 essential habitat, develop population indices for species at risk, and maintain healthy and productive ecological systems. Title: Comparative Characterization of Two Nearshore Rocky Reef Areas: A high-use recreational fishing reef vs. an unfished reef Author: Merems, Arlene, Appy, Marcus, Romsos, Chris, Weeks, Hal, Fox, David, Amend, Mark This project has provided the ODFW Marine Habitat Project with a unique opportunity to make a comparative examination of the habitats and fish communities of a heavily fished reef off of Siletz Bay, and a nearly unfished reef off Cape Perpetua. There are over 17,000 angler trips for groundfish out of Depoe Bay annually, many choosing to fish Siletz Reef. In addition, numerous whale watching and sightseeing charter vessels operate in the vicinity of the reef. Cape Perpetua Reef consists of isolated patches of rock, and is too far from Newport (the nearest port) to receive much fishing effort. This examination of the influences of fishing pressure in nearshore rocky habitat complements, and is embedded in, a broader effort to understand the distribution and character of Oregon’s nearshore rocky reefs, and the species that are dependent upon them for habitat. The ODFW Marine Habitat Project has spent the last eight years working in cooperation with scientists and other resource agencies to develop methods for classifying and mapping nearshore rocky reefs habitats off Oregon. Because nearshore reefs are in state waters, Oregon is responsible for managing these living resources and habitats to sustain their long-term use and productivity. To date, eight reefs have been surveyed and mapped with sidescan and/or multibeam bathymetry at a resolution indicative of fish habitat. ODFW has also been developing non-extractive fish survey techniques to describe fish-habitat associations and estimate fish abundance at the habitat and reef scale. The importance of habitat to reef species cannot be over-stated and is now widely accepted in the scientific community and is the focus of major research efforts in other Pacific coastal states. Better understanding of the degree to which harvest influences relative and absolute abundance, combined with species-habitat relationships, is essential for resource managers to exercise their stewardship responsibilities to protect 5 essential habitat, develop population indices for species at risk, and maintain healthy and productive ecological systems. Close

• 62. [Article] Woody riparian species patterns along northeast Oregon mountainous streams and the relationship to riparian capability

  Woody riparian vegetation is an essential component of riparian ecosystems, responsible in part for the maintenance of functional ecological processes. The plant community composition and distribution ...

  Citation × Citation Citation Abstract Copy Title: Woody riparian species patterns along northeast Oregon mountainous streams and the relationship to riparian capability Author: Yancey, Jennifer M. Woody riparian vegetation is an essential component of riparian ecosystems, responsible in part for the maintenance of functional ecological processes. The plant community composition and distribution provide an indication of the underlying mosaic of environmental attributes and processes. Restoration and management of riparian communities have been hindered by the lack of measurable criteria for the assessment of a riparian systems modified by human imposed infrastructures. The woody vegetation community offered a quantifiable indicator of the underlying mosaic of environmental, physical, and hydrological attributes, while allowing the investigation of the concept of riparian potential versus riparian capability. The examination of riparian condition was measured through the determination of species-environmental relationships along three mountainous channels in northeast Oregon. The physical and environmental attributes of channel morphology, hydrology, understory community composition, surface particle characteristics, and microclimate variables were quantified and analyzed in relation to the woody vegetation composition and distribution across the three separate streams and within flood-frequency elevation zones. The second component of the study evaluated and described methods for quantifying the concept of riparian capability, based on the measured species-environmental relationships and channel morphology. The evaluation of condition was measured against the reference baseline of Rosgen hierarchical classification and regional hydraulic geometry curves. Multivariate analyses indicated that vegetation transects grouped by stream and vegetation belt transects weakly grouped by flood zone, based on the species composition quantified within the vegetation transects and flood zones. Secondly, channel geometry, canopy cover, air temperature, channel particle size, understory composition attributes, and flood zone distance were found to be overall gradients, which described the variation in species composition across the three streams in northeast Oregon. Direct individual species-environmental relationship conclusions were weak due to the close clustering of species and multiple physical and environmental gradients. Riparian condition at the Grande Ronde River and North Fork Catherine Creek was determined to be functioning at riparian capability. Channel geometry measurements at the two stream reaches aligned with Rosgen stream type criteria and regional hydrologic curves, while species composition represented characteristics of potential natural communities. Meadow Creek was concluded to have departed from the highest attainable condition, thus riparian condition was less than capability. The results suggested that woody riparian vegetation response was a function the physical sttributes: channel morphological widths, bankfull, floodprone, 25-year flood width, valley width, channel sinuosity, and channel slope. Environmental attributes, floodplain canopy cover, air temperature, and understory composition, were further factors that influenced the woody riparian vegetation community variation. The results also suggested species richness and diversity were associated with specific physical and environmental attributes. Finally, the results provided the determination of riparian capability along montane streams in northeast Oregon and criteria acceptable for the determination of riparian capability. These criteria included the physical channel measurements assessed against Rosgen hierarchiecal classification and regional channel geometry curves; and woody vegetation presence and distribution assessed against potential natural community plant associations. Further research should be done across a variety of riparian systems to determine both indicator species and reference values for the physical and environmental attributes that could be utilized for the assessment of riparian capability. Title: Woody riparian species patterns along northeast Oregon mountainous streams and the relationship to riparian capability Author: Yancey, Jennifer M. Woody riparian vegetation is an essential component of riparian ecosystems, responsible in part for the maintenance of functional ecological processes. The plant community composition and distribution provide an indication of the underlying mosaic of environmental attributes and processes. Restoration and management of riparian communities have been hindered by the lack of measurable criteria for the assessment of a riparian systems modified by human imposed infrastructures. The woody vegetation community offered a quantifiable indicator of the underlying mosaic of environmental, physical, and hydrological attributes, while allowing the investigation of the concept of riparian potential versus riparian capability. The examination of riparian condition was measured through the determination of species-environmental relationships along three mountainous channels in northeast Oregon. The physical and environmental attributes of channel morphology, hydrology, understory community composition, surface particle characteristics, and microclimate variables were quantified and analyzed in relation to the woody vegetation composition and distribution across the three separate streams and within flood-frequency elevation zones. The second component of the study evaluated and described methods for quantifying the concept of riparian capability, based on the measured species-environmental relationships and channel morphology. The evaluation of condition was measured against the reference baseline of Rosgen hierarchical classification and regional hydraulic geometry curves. Multivariate analyses indicated that vegetation transects grouped by stream and vegetation belt transects weakly grouped by flood zone, based on the species composition quantified within the vegetation transects and flood zones. Secondly, channel geometry, canopy cover, air temperature, channel particle size, understory composition attributes, and flood zone distance were found to be overall gradients, which described the variation in species composition across the three streams in northeast Oregon. Direct individual species-environmental relationship conclusions were weak due to the close clustering of species and multiple physical and environmental gradients. Riparian condition at the Grande Ronde River and North Fork Catherine Creek was determined to be functioning at riparian capability. Channel geometry measurements at the two stream reaches aligned with Rosgen stream type criteria and regional hydrologic curves, while species composition represented characteristics of potential natural communities. Meadow Creek was concluded to have departed from the highest attainable condition, thus riparian condition was less than capability. The results suggested that woody riparian vegetation response was a function the physical sttributes: channel morphological widths, bankfull, floodprone, 25-year flood width, valley width, channel sinuosity, and channel slope. Environmental attributes, floodplain canopy cover, air temperature, and understory composition, were further factors that influenced the woody riparian vegetation community variation. The results also suggested species richness and diversity were associated with specific physical and environmental attributes. Finally, the results provided the determination of riparian capability along montane streams in northeast Oregon and criteria acceptable for the determination of riparian capability. These criteria included the physical channel measurements assessed against Rosgen hierarchiecal classification and regional channel geometry curves; and woody vegetation presence and distribution assessed against potential natural community plant associations. Further research should be done across a variety of riparian systems to determine both indicator species and reference values for the physical and environmental attributes that could be utilized for the assessment of riparian capability. Close

• 63. [Article] Tradeoffs associated with managing forested landscapes for multiple-uses

  This study focuses on the tradeoffs that exist for managing forested landscapes for biodiversity and timber production. Tradeoff evaluation is important to natural resource managers so they can understand ...

  Citation × Citation Citation Abstract Copy Title: Tradeoffs associated with managing forested landscapes for multiple-uses Author: Lichtenstein, Mark E. This study focuses on the tradeoffs that exist for managing forested landscapes for biodiversity and timber production. Tradeoff evaluation is important to natural resource managers so they can understand the benefits and costs of alternative management prescriptions. The study examines three watersheds in the Oregon Coast Range and 166 terrestrial vertebrate species to determine the productive capacity of the site in terms of biodiversity and timber revenue. Two points are identified that maximize biodiversity and maximize timber revenue that serve as corner solutions for the production possibilities frontier for biodiversity and timber revenue. The frontier identifies all combinations of outputs that are equal in productive efficiency and the slope of the frontier identifies the marginal cost of biodiversity in terms of foregone timber revenue. A special case is then examined that reenacts the proposed management intentions of each ownership group in the study area. The special case model is used to examine the level of efficiency that exists with respect to the productive possibilities frontier. The results of the study indicate that there is a high level of inefficiency in the proposed management intentions of the various ownership groups. Higher levels of revenues can be achieved at the same level of biodiversity. Conversely more biodiversity can be produced at the same level of revenue. Marginal cost analysis also showed that biodiversity comes at an increasingly high cost at the extreme end of the productive capability of the study area. Results also indicate the species that are most affected by management activities are those that require large home ranges (> 200 acres) and species that are the most taxonomically unique. Title: Tradeoffs associated with managing forested landscapes for multiple-uses Author: Lichtenstein, Mark E. This study focuses on the tradeoffs that exist for managing forested landscapes for biodiversity and timber production. Tradeoff evaluation is important to natural resource managers so they can understand the benefits and costs of alternative management prescriptions. The study examines three watersheds in the Oregon Coast Range and 166 terrestrial vertebrate species to determine the productive capacity of the site in terms of biodiversity and timber revenue. Two points are identified that maximize biodiversity and maximize timber revenue that serve as corner solutions for the production possibilities frontier for biodiversity and timber revenue. The frontier identifies all combinations of outputs that are equal in productive efficiency and the slope of the frontier identifies the marginal cost of biodiversity in terms of foregone timber revenue. A special case is then examined that reenacts the proposed management intentions of each ownership group in the study area. The special case model is used to examine the level of efficiency that exists with respect to the productive possibilities frontier. The results of the study indicate that there is a high level of inefficiency in the proposed management intentions of the various ownership groups. Higher levels of revenues can be achieved at the same level of biodiversity. Conversely more biodiversity can be produced at the same level of revenue. Marginal cost analysis also showed that biodiversity comes at an increasingly high cost at the extreme end of the productive capability of the study area. Results also indicate the species that are most affected by management activities are those that require large home ranges (> 200 acres) and species that are the most taxonomically unique. Close

• 64. [Article] Hydrologic and vegetation responses associated with restoration of wetlands in the Willamette Valley, Oregon

  I examined hydrological and plant community changes associated with the implementation of a restoration management plan in two riparian meadows located within an agricultural landscape of the central Willamette ...

  Citation × Citation Citation Abstract Copy Title: Hydrologic and vegetation responses associated with restoration of wetlands in the Willamette Valley, Oregon Author: Coleman, Gregory A. I examined hydrological and plant community changes associated with the implementation of a restoration management plan in two riparian meadows located within an agricultural landscape of the central Willamette Valley, Oregon. I established exclosure fencing (a form of passive restoration) in one agricultural field and established fencing and plugged a drainage ditch (active restoration) in a separate agricultural field. Permanent transects 15 m in length were established within two plant communities associated with hydrological regimes within these restored agricultural fields. Plant communities were classified as wetland meadow (inundated for more than 4 weeks/year) and mesic meadow (saturated within the upper 30 cm but not inundated) for at least 4 weeks/year. Four transects were randomly established within the wet meadow community and 6 transects were randomly situated within the mesic meadow community. Two shallow subsurface piezometers were installed to a depth of 1 m at 5 m and 10 m along each of these 15 m transects. Additionally, two shallow sub-surface piezometers were established at the outer perimeter of the agriculturally excluded fields. Shallow sub-surface and surface water table levels were measured at each piezometer after wetlands were inundated and continued until water table dropped below the piezometers (Dec. - June) for one pre-treatment and two post treatment years. The actively restored wet and mesic meadows demonstrated increased water table elevation and a decrease in water table fluctuation during both post treatment years. Increases in water table elevation were greatest in areas closest to active restoration but were significant up to 102 m. from restoration. Results indicate that filling drainage ditches induce hydrologic effects at great distances across floodplain soils. Plant community composition (species response) was quantified in both restored sites as well as the adjacent agriculturally managed (untreated) sites one year before treatment and two post-treatment years. I sampled two plant community types: wet meadow and mesic meadow. I calculated species richness and the relative abundance of wetland indicator species, nuisance weeds, and native plants. Nuisance weeds increased and native plant abundance decreased in agriculturally managed mesic meadows. Wetland plant species abundance tended to increase in agricultural sites with light grazing, and decreased in areas that were plowed and re-seeded. Native plants increased and nuisance weeds decreased in the actively restored mesic meadow. The passively restored mesic meadow exhibited no change in native plant abundance and decreases in all other categories. In the actively restored wetland there were increases in plant species richness and nuisance weed abundance with a decrease in native plant abundance. Agriculturally excluded wetlands dominated by Reed canary grass (Phalaris arundinacea) exhibited no changes for the entire study period. Results suggest that for the first few years following agricultural exclusion, nuisance weed species do not increase, but active restoration may result in increases (due to disturbance). Additionally, results indicate restored agricultural landscapes dominated by introduced grasses demonstrate minimal short-term plant community change unless initiated by intense land management practices (e g., plowing, re-seeding, or removal of dominant plant communities). Based upon results of this study, I conclude that restoration plans should repair damaged hydrological features before planting riparian plant species. Following this chronological sequence will minimize the potential destruction of planted communities by future shifts in water table elevation caused by hydrologic restoration. Furthermore, any active restoration that initiates a direct or indirect removal of the dominant plant community should be accompanied by aggressive plantings of desirable plant species and prolonged site maintenance. Title: Hydrologic and vegetation responses associated with restoration of wetlands in the Willamette Valley, Oregon Author: Coleman, Gregory A. I examined hydrological and plant community changes associated with the implementation of a restoration management plan in two riparian meadows located within an agricultural landscape of the central Willamette Valley, Oregon. I established exclosure fencing (a form of passive restoration) in one agricultural field and established fencing and plugged a drainage ditch (active restoration) in a separate agricultural field. Permanent transects 15 m in length were established within two plant communities associated with hydrological regimes within these restored agricultural fields. Plant communities were classified as wetland meadow (inundated for more than 4 weeks/year) and mesic meadow (saturated within the upper 30 cm but not inundated) for at least 4 weeks/year. Four transects were randomly established within the wet meadow community and 6 transects were randomly situated within the mesic meadow community. Two shallow subsurface piezometers were installed to a depth of 1 m at 5 m and 10 m along each of these 15 m transects. Additionally, two shallow sub-surface piezometers were established at the outer perimeter of the agriculturally excluded fields. Shallow sub-surface and surface water table levels were measured at each piezometer after wetlands were inundated and continued until water table dropped below the piezometers (Dec. - June) for one pre-treatment and two post treatment years. The actively restored wet and mesic meadows demonstrated increased water table elevation and a decrease in water table fluctuation during both post treatment years. Increases in water table elevation were greatest in areas closest to active restoration but were significant up to 102 m. from restoration. Results indicate that filling drainage ditches induce hydrologic effects at great distances across floodplain soils. Plant community composition (species response) was quantified in both restored sites as well as the adjacent agriculturally managed (untreated) sites one year before treatment and two post-treatment years. I sampled two plant community types: wet meadow and mesic meadow. I calculated species richness and the relative abundance of wetland indicator species, nuisance weeds, and native plants. Nuisance weeds increased and native plant abundance decreased in agriculturally managed mesic meadows. Wetland plant species abundance tended to increase in agricultural sites with light grazing, and decreased in areas that were plowed and re-seeded. Native plants increased and nuisance weeds decreased in the actively restored mesic meadow. The passively restored mesic meadow exhibited no change in native plant abundance and decreases in all other categories. In the actively restored wetland there were increases in plant species richness and nuisance weed abundance with a decrease in native plant abundance. Agriculturally excluded wetlands dominated by Reed canary grass (Phalaris arundinacea) exhibited no changes for the entire study period. Results suggest that for the first few years following agricultural exclusion, nuisance weed species do not increase, but active restoration may result in increases (due to disturbance). Additionally, results indicate restored agricultural landscapes dominated by introduced grasses demonstrate minimal short-term plant community change unless initiated by intense land management practices (e g., plowing, re-seeding, or removal of dominant plant communities). Based upon results of this study, I conclude that restoration plans should repair damaged hydrological features before planting riparian plant species. Following this chronological sequence will minimize the potential destruction of planted communities by future shifts in water table elevation caused by hydrologic restoration. Furthermore, any active restoration that initiates a direct or indirect removal of the dominant plant community should be accompanied by aggressive plantings of desirable plant species and prolonged site maintenance. Close

• 65. [Article] Ecology and biological control of an apomictic invasive plant, Chondrilla juncea (Asteraceae)

  A study consisting of three parts was undertaken to investigate how variation in species interactions, population genetic structure, epidemiological parameters, and plant breeding system may influence ...

  Citation × Citation Citation Abstract Copy Title: Ecology and biological control of an apomictic invasive plant, Chondrilla juncea (Asteraceae) Author: Campanella, Donald Michael A study consisting of three parts was undertaken to investigate how variation in species interactions, population genetic structure, epidemiological parameters, and plant breeding system may influence the ecology and biological control of an apomictic invasive plant, Chondrilla juncea (Asteraceae). Interactions between natural enemy species may modify their net effect on host plants, but little research has been done to examine how plant resistance influences species interactions in biological weed control. First, we performed common garden experiments with clonal accessions of C. juncea to compare a rust-susceptible weed biotype with a rust-resistant biotype, both of which are invasive in western North America. Inoculations with two biological control organisms, a rust fungus pathogen (Puccinia chondrillina) and an eriophyid gall mite (Eriophyes chondrillae), were applied separately and in combination to test if plant performance is modified by antagonistic or facilitative species interactions. We found no significant rust x mite interaction effects for several plant traits (shoot length, shoot dry biomass, fecundity, rosette growth, and rosette senescence), and therefore the two natural enemies appear to have independent and complementary effects on plant performance. However, rust inoculation reduced the total dry biomass of mite galls in the rust-susceptible biotype by indirect competition due to decreased growth of diseased shoots, but not in the rust-resistant biotype. Our results indicate that rust disease may have the potential to modify mite gall epidemiology and relative plant performance in mixed populations of resistant and susceptible C. juncea biotypes. In the second part of the study, a monitoring survey of C. juncea was conducted in southwest Oregon during 2006 to investigate natural associations in the distribution of damage caused by P. chondrillina, E. chondrillae, and the cecidomyiid gall midge Cystiphora schmidti. Mite galling was the most aggregated type of damage both within and among field sites. Analysis of an allometric relationship of shoot growth (biomass versus stem area) indicates that rust disease reduced C. juncea growth but only at high stand density, and in general rust disease was the most randomly distributed type of damage within sites. There was no evidence from the field survey to support a species interaction between the gall mite and the rust pathogen, but negative associations were detected between midge galling and the damage caused by both of the other natural enemies, which may indicate species interaction via rust and/or mite interference with C. schmidti oviposition. However, this potential antagonism was found only at high stand density with relatively high levels of damage caused by each natural enemy, and so the overall impact of biological control probably is not strongly diminished by enemy interference. The third part of the study was a mathematical model of inheritance and genetic equilibrium in meiotic diplospory, which is an unusual mechanism of gametophytic apomixis occurring in invasive populations of C. juncea and also in triploid dandelions (Taraxacum officinale). Crossing-over during prophase I of meiotic diplospory has the potential to generate genotypic diversity in apomictic lineages because it involves homologous recombination without fertilization ("subsexual reproduction"). I developed a stage-structured matrix model of inheritance in subsexual reproduction using a wide range of probabilities for recombination and mutation to assess the range of equilibrium conditions under which genotypic diversity is stable in obligately apomictic lines. The analysis supports predictions of genotypic diversity when rates of crossing-over and mutation are not highly imbalanced. Therefore subsexual reproduction remains mathematically plausible as a contributing factor to the quantitative variation in disease resistance and ecological traits of invasive C. juncea found in this study and others. Title: Ecology and biological control of an apomictic invasive plant, Chondrilla juncea (Asteraceae) Author: Campanella, Donald Michael A study consisting of three parts was undertaken to investigate how variation in species interactions, population genetic structure, epidemiological parameters, and plant breeding system may influence the ecology and biological control of an apomictic invasive plant, Chondrilla juncea (Asteraceae). Interactions between natural enemy species may modify their net effect on host plants, but little research has been done to examine how plant resistance influences species interactions in biological weed control. First, we performed common garden experiments with clonal accessions of C. juncea to compare a rust-susceptible weed biotype with a rust-resistant biotype, both of which are invasive in western North America. Inoculations with two biological control organisms, a rust fungus pathogen (Puccinia chondrillina) and an eriophyid gall mite (Eriophyes chondrillae), were applied separately and in combination to test if plant performance is modified by antagonistic or facilitative species interactions. We found no significant rust x mite interaction effects for several plant traits (shoot length, shoot dry biomass, fecundity, rosette growth, and rosette senescence), and therefore the two natural enemies appear to have independent and complementary effects on plant performance. However, rust inoculation reduced the total dry biomass of mite galls in the rust-susceptible biotype by indirect competition due to decreased growth of diseased shoots, but not in the rust-resistant biotype. Our results indicate that rust disease may have the potential to modify mite gall epidemiology and relative plant performance in mixed populations of resistant and susceptible C. juncea biotypes. In the second part of the study, a monitoring survey of C. juncea was conducted in southwest Oregon during 2006 to investigate natural associations in the distribution of damage caused by P. chondrillina, E. chondrillae, and the cecidomyiid gall midge Cystiphora schmidti. Mite galling was the most aggregated type of damage both within and among field sites. Analysis of an allometric relationship of shoot growth (biomass versus stem area) indicates that rust disease reduced C. juncea growth but only at high stand density, and in general rust disease was the most randomly distributed type of damage within sites. There was no evidence from the field survey to support a species interaction between the gall mite and the rust pathogen, but negative associations were detected between midge galling and the damage caused by both of the other natural enemies, which may indicate species interaction via rust and/or mite interference with C. schmidti oviposition. However, this potential antagonism was found only at high stand density with relatively high levels of damage caused by each natural enemy, and so the overall impact of biological control probably is not strongly diminished by enemy interference. The third part of the study was a mathematical model of inheritance and genetic equilibrium in meiotic diplospory, which is an unusual mechanism of gametophytic apomixis occurring in invasive populations of C. juncea and also in triploid dandelions (Taraxacum officinale). Crossing-over during prophase I of meiotic diplospory has the potential to generate genotypic diversity in apomictic lineages because it involves homologous recombination without fertilization ("subsexual reproduction"). I developed a stage-structured matrix model of inheritance in subsexual reproduction using a wide range of probabilities for recombination and mutation to assess the range of equilibrium conditions under which genotypic diversity is stable in obligately apomictic lines. The analysis supports predictions of genotypic diversity when rates of crossing-over and mutation are not highly imbalanced. Therefore subsexual reproduction remains mathematically plausible as a contributing factor to the quantitative variation in disease resistance and ecological traits of invasive C. juncea found in this study and others. Close

• 66. [Article] Trophic dynamics of marine nekton and zooplankton in the Northern California Current ecosystem

  The Northern California Current (NCC) ecosystem exhibits extreme seasonal, interannual and interdecadal shifts in the abiotic environment and shifts in primary and higher production. This variability is ...

  Citation × Citation Citation Abstract Copy Title: Trophic dynamics of marine nekton and zooplankton in the Northern California Current ecosystem Author: Miller, Todd William The Northern California Current (NCC) ecosystem exhibits extreme seasonal, interannual and interdecadal shifts in the abiotic environment and shifts in primary and higher production. This variability is also apparent in the spatial structure of the ecosystem with nearshore-shelf waters (<150 m isobath) being highly productive and having a different community structure relative to more offshore-slope (>150 m) waters. Very little is known of the trophic relationships between primary consumers and higher trophic levels within this system, and the potential influence of spatial gradients in productivity and community composition on trophic structure. This dissertation research covers several important aspects of trophic dynamics within the NCC ecosystem through the use of conventional dietary analysis and stable isotope analysis of multiple trophic levels. From June and August 2000 and 2002 cruises off the shelf-slope ecosystem from Northern California to central Oregon, I collected and analyzed the diets from 25 species of pelagic nekton (Chapter 2). Trophic groups were formed from agglomerative hierarchical cluster analysis of prey contribution to nekton diet, with cluster groups described by indicator species analysis. Seasonal, interannual and interdecadal comparisons in diet were examined for some nekton species. Results from general description of diets and cluster analysis showed clustering based primarily on prey of copepods, euphausiids, decapod larvae and larval-juvenile fishes, representing lower (copepods), middle (euphausiids and decapod larvae) and upper (larval-juvenile fishes) trophic groups, but that many species exhibited omnivory by feeding on prey several levels down the food web. Results from carbon and nitrogen stable isotope analysis (Chapter 3) support the general trophic structure observed through dietary analysis; that the copepod-euphausiid-larval/juvenile fish structure in the diets were generally observed in relative trophic position using δ15N. Carbon stable isotopes displayed signatures more indicative of onshore-offshore distribution of species (Chapter 4) with nearshore species of nekton and zooplankton being enriched in 13C relative to offshore. This provided an effective trophically-based delineation of the NCC pelagic food web. Although stable isotopes are effective tools for measuring relative trophic position and source production, the duration of time that stable isotopes are a measure of past trophic hsitory is not well known. To examine this, I conducted a laboratory-controlled experiment to examine the tissue-specific response of isotope δ15N to changes in isotopic signature of diet in an adult marine fish (Pacific herring, Clupea pallasi)(Chapter 5). To test which animal tissue was the most accurate measure of isotope shift I examined multiple tissues (eye, heart, liver, blood, and white muscle) and the importance of growth and metabolism in this shift. This study showed that (i) isotopic response of individual tissues following an isotopic shift in diet varied in both rate of change and fractionation level, (ii) most of this isotopic shift is due to growth, and (iii) white muscle and liver tissue appeared the most responsive to isotopic shift in diet, reaching isotopic equilibrium with diet in a matter of months (not years). The culmination of this dissertation in the context of trophic controls on the NCC ecosystem, and how they are different from other EBC systems are discussed in Chapter 6. Title: Trophic dynamics of marine nekton and zooplankton in the Northern California Current ecosystem Author: Miller, Todd William The Northern California Current (NCC) ecosystem exhibits extreme seasonal, interannual and interdecadal shifts in the abiotic environment and shifts in primary and higher production. This variability is also apparent in the spatial structure of the ecosystem with nearshore-shelf waters (<150 m isobath) being highly productive and having a different community structure relative to more offshore-slope (>150 m) waters. Very little is known of the trophic relationships between primary consumers and higher trophic levels within this system, and the potential influence of spatial gradients in productivity and community composition on trophic structure. This dissertation research covers several important aspects of trophic dynamics within the NCC ecosystem through the use of conventional dietary analysis and stable isotope analysis of multiple trophic levels. From June and August 2000 and 2002 cruises off the shelf-slope ecosystem from Northern California to central Oregon, I collected and analyzed the diets from 25 species of pelagic nekton (Chapter 2). Trophic groups were formed from agglomerative hierarchical cluster analysis of prey contribution to nekton diet, with cluster groups described by indicator species analysis. Seasonal, interannual and interdecadal comparisons in diet were examined for some nekton species. Results from general description of diets and cluster analysis showed clustering based primarily on prey of copepods, euphausiids, decapod larvae and larval-juvenile fishes, representing lower (copepods), middle (euphausiids and decapod larvae) and upper (larval-juvenile fishes) trophic groups, but that many species exhibited omnivory by feeding on prey several levels down the food web. Results from carbon and nitrogen stable isotope analysis (Chapter 3) support the general trophic structure observed through dietary analysis; that the copepod-euphausiid-larval/juvenile fish structure in the diets were generally observed in relative trophic position using δ15N. Carbon stable isotopes displayed signatures more indicative of onshore-offshore distribution of species (Chapter 4) with nearshore species of nekton and zooplankton being enriched in 13C relative to offshore. This provided an effective trophically-based delineation of the NCC pelagic food web. Although stable isotopes are effective tools for measuring relative trophic position and source production, the duration of time that stable isotopes are a measure of past trophic hsitory is not well known. To examine this, I conducted a laboratory-controlled experiment to examine the tissue-specific response of isotope δ15N to changes in isotopic signature of diet in an adult marine fish (Pacific herring, Clupea pallasi)(Chapter 5). To test which animal tissue was the most accurate measure of isotope shift I examined multiple tissues (eye, heart, liver, blood, and white muscle) and the importance of growth and metabolism in this shift. This study showed that (i) isotopic response of individual tissues following an isotopic shift in diet varied in both rate of change and fractionation level, (ii) most of this isotopic shift is due to growth, and (iii) white muscle and liver tissue appeared the most responsive to isotopic shift in diet, reaching isotopic equilibrium with diet in a matter of months (not years). The culmination of this dissertation in the context of trophic controls on the NCC ecosystem, and how they are different from other EBC systems are discussed in Chapter 6. Close

• 67. [Article] Reconnaissance botany of alpine ecosystems on Prince of Wales Island, southeast Alaska

  A study of the Prince of Wales Island alpine areas was undertaken to determine what species occur in the region and to describe plant communities making up the alpine vegetation. For one month in 1972, ...

  Citation × Citation Citation Abstract Copy Title: Reconnaissance botany of alpine ecosystems on Prince of Wales Island, southeast Alaska Author: Jaques, Dennis Randall A study of the Prince of Wales Island alpine areas was undertaken to determine what species occur in the region and to describe plant communities making up the alpine vegetation. For one month in 1972, specimens were collected and 78 micro-plots were analyzed for cover, frequency and constancy data. Three basic habitat types were discovered, with different associations being recognized on calcareous and noncalcareous substrates. Alpine vegetation patterns are formed in a physiographically unstable area. However, where conditions remain favorable for a long enough period of time, a climatic climax of Empetrum-heath vegetation develops. Elsewhere topographic climax vegetation exists. The region is thought to have maintained a flora of significant proportions at least since early post-Pleistocene time. The presence of many disjunct species indicates that floral elements may have survived Pleistocene ice advances in various refugial sites. The west coast of Prince of Wales Island appears to have served as a small migration center following Pleistocene ice recession. Title: Reconnaissance botany of alpine ecosystems on Prince of Wales Island, southeast Alaska Author: Jaques, Dennis Randall A study of the Prince of Wales Island alpine areas was undertaken to determine what species occur in the region and to describe plant communities making up the alpine vegetation. For one month in 1972, specimens were collected and 78 micro-plots were analyzed for cover, frequency and constancy data. Three basic habitat types were discovered, with different associations being recognized on calcareous and noncalcareous substrates. Alpine vegetation patterns are formed in a physiographically unstable area. However, where conditions remain favorable for a long enough period of time, a climatic climax of Empetrum-heath vegetation develops. Elsewhere topographic climax vegetation exists. The region is thought to have maintained a flora of significant proportions at least since early post-Pleistocene time. The presence of many disjunct species indicates that floral elements may have survived Pleistocene ice advances in various refugial sites. The west coast of Prince of Wales Island appears to have served as a small migration center following Pleistocene ice recession. Close

• 68. [Article] El Nino related variations in nutrient and chlorophyll distributions off Oregon

  The Oregon continental shelf waters are typically characterized by four to five major upwelling events that occur between May and October. The upwelled water is rich in nutrients, which fuels an increase ...

  Citation × Citation Citation Abstract Copy Title: El Nino related variations in nutrient and chlorophyll distributions off Oregon Author: Corwith, Holly L. The Oregon continental shelf waters are typically characterized by four to five major upwelling events that occur between May and October. The upwelled water is rich in nutrients, which fuels an increase in phytoplankton biomass. The onset of El Nino, however, can disrupt the normal physical processes along the Oregon coastline by decreasing upwelling, thereby potentially changing the distribution of nutrients and chlorophyll in this region. As part of the Eastern North Pacific GLOBEC program, we have examined the direct effect of El Nino on nutrient and chlorophyll distributions along the Oregon coast. We sampled chlorophyll and nutrients (phosphate, silicate, nitrate, nitrite, and ammonium) from September 1997 through July 1999 along 4 lines from 40°52.0' to 44°39.1'. Results showed that the shelf was nitrate limited, and chlorophyll concentrations were significantly lower off Newport during the El Nino summer. The percentage of large sized cells (> 10 gm) was decreased to 23% of the total population, as compared to 92% found during the more typical upwelling conditions in August. 1998, which indicates a species composition change occurred during the El Nino period. The slope and offshore waters were less affected by the El Nino conditions during the upwelling season. Title: El Nino related variations in nutrient and chlorophyll distributions off Oregon Author: Corwith, Holly L. The Oregon continental shelf waters are typically characterized by four to five major upwelling events that occur between May and October. The upwelled water is rich in nutrients, which fuels an increase in phytoplankton biomass. The onset of El Nino, however, can disrupt the normal physical processes along the Oregon coastline by decreasing upwelling, thereby potentially changing the distribution of nutrients and chlorophyll in this region. As part of the Eastern North Pacific GLOBEC program, we have examined the direct effect of El Nino on nutrient and chlorophyll distributions along the Oregon coast. We sampled chlorophyll and nutrients (phosphate, silicate, nitrate, nitrite, and ammonium) from September 1997 through July 1999 along 4 lines from 40°52.0' to 44°39.1'. Results showed that the shelf was nitrate limited, and chlorophyll concentrations were significantly lower off Newport during the El Nino summer. The percentage of large sized cells (> 10 gm) was decreased to 23% of the total population, as compared to 92% found during the more typical upwelling conditions in August. 1998, which indicates a species composition change occurred during the El Nino period. The slope and offshore waters were less affected by the El Nino conditions during the upwelling season. Close

• 69. [Article] Lidar-derived canopy architecture predicts brown creeper occupancy of two western coniferous forests

  This is the publisher’s final pdf. The published article is copyrighted by The Cooper Ornithological Society and can be found at: http://www.cooper.org/.

  Citation × Citation Citation Abstract Copy Title: Lidar-derived canopy architecture predicts brown creeper occupancy of two western coniferous forests Author: Vogeler, Jody C., Vierling, Lee A., Vierling, Kerri T., Hudak, Andrew T. This is the publisher’s final pdf. The published article is copyrighted by The Cooper Ornithological Society and can be found at: http://www.cooper.org/. Title: Lidar-derived canopy architecture predicts brown creeper occupancy of two western coniferous forests Author: Vogeler, Jody C., Vierling, Lee A., Vierling, Kerri T., Hudak, Andrew T. This is the publisher’s final pdf. The published article is copyrighted by The Cooper Ornithological Society and can be found at: http://www.cooper.org/. Close

• 70. [Article] Species associations and redundancy in relation to biological hotspots within the northern California Current ecosystem

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier ...

  Citation × Citation Citation Abstract Copy Title: Species associations and redundancy in relation to biological hotspots within the northern California Current ecosystem Author: Reese, Douglas C., Brodeur, Richard D. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/journal-of-marine-systems/. Title: Species associations and redundancy in relation to biological hotspots within the northern California Current ecosystem Author: Reese, Douglas C., Brodeur, Richard D. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/journal-of-marine-systems/. Close

• 71. [Article] Effects of pesticides on amphibians with special reference to the pyrethroid insecticide, cypermethrin

  Pollution by pesticides is a ubiquitous concern for wildlife. The effects of pesticides are especially concerning in aquatic environments, which are particularly vulnerable as they have several exposure ...

  Citation × Citation Citation Abstract Copy Title: Effects of pesticides on amphibians with special reference to the pyrethroid insecticide, cypermethrin Author: Biga, Lindsay M. Pollution by pesticides is a ubiquitous concern for wildlife. The effects of pesticides are especially concerning in aquatic environments, which are particularly vulnerable as they have several exposure routes for the influx of chemicals. These effects are of particular concern as biodiversity loss reaches unprecedented rates. This includes recent declines of amphibian populations and loss of amphibian species. Pesticide exposure may contribute to some amphibian populations and extinctions. This dissertation explores the effects of pesticides on amphibians, with particular reference to the pyrethroid insecticide cypermethrin. I first synthesized acute toxicity data of pesticides for amphibians from the literature (Chapter 2). Using 96h LC50 values for amphibian larvae exposed to insecticides, herbicides, and fungicides, I determined that amphibian species cannot be systematically classified as sensitive or tolerant to pesticides. Rather, relative acute lethal toxicities varied among species and between chemicals and types of pesticides even within a species, indicating that no amphibian species from this analysis can represent anticipated toxic effects to all amphibians. I next examined the differences in sensitivity to cypermethrin among three developmental stages for three anuran (frog) species (Chapter 3). I experimentally exposed embryos, recently hatched larvae and larvae with limb buds to cypermethrin in the laboratory. Exposure to cypermethrin had lethal and sublethal effects on some species and stages, but not all. The Pacific treefrog (Pseudacris regilla) was the most sensitive species and the early larval stage was the most sensitive for these three species. Additionally, cypermethrin exposure induced abnormal behavior in response to prodding for some species and stages. These results indicate differences in sensitivity to cypermethrin among species of amphibians. To further understand differences in sensitivity to pesticides among amphibians, I compared how three populations of P. regilla responded to cypermethrin exposure (Chapter 4). I performed a time-to-death assay in the laboratory, exposing newly hatched larvae from each population to cypermethrin under identical conditions. All populations had high rates of mortality when exposed to cypermethrin compared to unexposed controls and populations varied in the time to death. Moreover, exposed individuals were smaller than unexposed controls. Interestingly, population sensitivity did not appear to be associated with proximity to agriculture, but rather with elevation gradient, indicating that an evolved tolerance to pesticide exposure is not the mechanism for the differences in sensitivity observed here. To investigate the effects of cypermethrin on amphibians within a community context, I studied exposure in mesocosms (Chapter 5). I set up semi-natural aquatic ponds in enclosures that contained zooplankton, phytoplankton, and periphyton along with amphibian larvae. I experimentally exposed these mesocosms to cypermethrin and measured the effects on the amphibians and the other members of the community. Cypermethrin affected the entire aquatic community, even at the lowest dose, indicating the direct and indirect deleterious effects of cypermethrin on both invertebrate and vertebrate species in an aquatic community. This dissertation provides needed data on the effects of the pyrethroid insecticide cypermethrin on amphibians and their communities. Understanding the toxicity of newer, commonly used pesticides to non-target organisms is important as conservation biologists and managers make efforts to combat future amphibian population declines which may be associated with chemicals in the environment. Title: Effects of pesticides on amphibians with special reference to the pyrethroid insecticide, cypermethrin Author: Biga, Lindsay M. Pollution by pesticides is a ubiquitous concern for wildlife. The effects of pesticides are especially concerning in aquatic environments, which are particularly vulnerable as they have several exposure routes for the influx of chemicals. These effects are of particular concern as biodiversity loss reaches unprecedented rates. This includes recent declines of amphibian populations and loss of amphibian species. Pesticide exposure may contribute to some amphibian populations and extinctions. This dissertation explores the effects of pesticides on amphibians, with particular reference to the pyrethroid insecticide cypermethrin. I first synthesized acute toxicity data of pesticides for amphibians from the literature (Chapter 2). Using 96h LC50 values for amphibian larvae exposed to insecticides, herbicides, and fungicides, I determined that amphibian species cannot be systematically classified as sensitive or tolerant to pesticides. Rather, relative acute lethal toxicities varied among species and between chemicals and types of pesticides even within a species, indicating that no amphibian species from this analysis can represent anticipated toxic effects to all amphibians. I next examined the differences in sensitivity to cypermethrin among three developmental stages for three anuran (frog) species (Chapter 3). I experimentally exposed embryos, recently hatched larvae and larvae with limb buds to cypermethrin in the laboratory. Exposure to cypermethrin had lethal and sublethal effects on some species and stages, but not all. The Pacific treefrog (Pseudacris regilla) was the most sensitive species and the early larval stage was the most sensitive for these three species. Additionally, cypermethrin exposure induced abnormal behavior in response to prodding for some species and stages. These results indicate differences in sensitivity to cypermethrin among species of amphibians. To further understand differences in sensitivity to pesticides among amphibians, I compared how three populations of P. regilla responded to cypermethrin exposure (Chapter 4). I performed a time-to-death assay in the laboratory, exposing newly hatched larvae from each population to cypermethrin under identical conditions. All populations had high rates of mortality when exposed to cypermethrin compared to unexposed controls and populations varied in the time to death. Moreover, exposed individuals were smaller than unexposed controls. Interestingly, population sensitivity did not appear to be associated with proximity to agriculture, but rather with elevation gradient, indicating that an evolved tolerance to pesticide exposure is not the mechanism for the differences in sensitivity observed here. To investigate the effects of cypermethrin on amphibians within a community context, I studied exposure in mesocosms (Chapter 5). I set up semi-natural aquatic ponds in enclosures that contained zooplankton, phytoplankton, and periphyton along with amphibian larvae. I experimentally exposed these mesocosms to cypermethrin and measured the effects on the amphibians and the other members of the community. Cypermethrin affected the entire aquatic community, even at the lowest dose, indicating the direct and indirect deleterious effects of cypermethrin on both invertebrate and vertebrate species in an aquatic community. This dissertation provides needed data on the effects of the pyrethroid insecticide cypermethrin on amphibians and their communities. Understanding the toxicity of newer, commonly used pesticides to non-target organisms is important as conservation biologists and managers make efforts to combat future amphibian population declines which may be associated with chemicals in the environment. Close

• 72. [Article] Habitat use and movement behavior of Pacific marten (Martes caurina) in response to forest management practices in Lassen National Forest, California

  Some of the most pressing conservation concerns involve declining populations of species with low fecundity and highly specialized foraging and reproductive requirements. Yet, we often lack a functional ...

  Citation × Citation Citation Abstract Copy Title: Habitat use and movement behavior of Pacific marten (Martes caurina) in response to forest management practices in Lassen National Forest, California Author: Moriarty, Katie M. Some of the most pressing conservation concerns involve declining populations of species with low fecundity and highly specialized foraging and reproductive requirements. Yet, we often lack a functional understanding of how individuals of those species interact with their environment, specifically how their movement is affected by human-induced changes. In order to maintain connectivity and viable populations, public land managers require science to inform how changes in structure affect the individual movements and thus population connectivity of sensitive species. I collected detailed movement data on Pacific martens (Martes caurina) in Lassen National Forest, California, during 2010-2013. Martens are small carnivores that are closely associated with old forest elements (e.g., large snags and logs). Marten populations rapidly decline with loss and fragmentation of forest cover. As such, martens are a U.S. Forest Service Management Indicator Species and a Species of Special Concern in the state of California. My goal was to understand martens' behavior in forest patches that were altered by thinning to remove ladder fuels-small diameter trees, understory vegetation, and branches near the ground. Such fuels treatments are increasingly prevalent on public lands, especially in dry forests, to reduce risk of high-severity and high-intensity fire. Although previous research suggested martens selection for dense forest and avoid gaps in forest cover, no information was available describing martens' use of simplified thinned patches. The objectives of my dissertation were to: (1) test whether marten movement and activity could accurately be measured using miniature GPS collars, and (2) evaluate marten use, selection, and behavior in patches that differed in structural complexity. Global positioning system (GPS) telemetry provides opportunities to collect detailed information from free-ranging animals with a high degree of precision and accuracy. Miniature GPS collars (42-60g) have only been available since 2009 for mammals and have not been consistently effective. Furthermore, all GPS units suffer from non-random data loss and location error, which is often exacerbated by dense vegetation. Given these constraints, it was questionable whether GPS collars would be an effective tool for studying martens. In Chapter 1, I evaluated how satellite data and environmental conditions affected performance of GPS units. I used a paired experimental design and programmed the GPS unit to retain or remove satellite data before attempting a location (fix). I found that short intervals between fix attempts significantly increased the likelihood of fix success. Locations estimated using at least 4 satellites were, on average, within 28 m of the actual location regardless of vegetation cover. Thus, location estimates at short intervals with >4 satellites were not typically biased by dense vegetation. Accurate fine-scale information on martens was necessary to quantify and interpret patch use and habitat selection. I evaluated martens’ use and behavior in three forest patch types that differed in structural complexity (complex, simple, and open). In Chapter 2, I quantified use patch use in two seasons–summer and winter. I used food-titration experiments to standardize motivation of martens to enter different patch types and compared these short-term incentivized experiments with year-round observational telemetry data (GPS and very high frequency telemetry). Martens selected complex patches and avoided both simple patches and openings, but not equivalently–openings were strongly avoided. With baited incentive, martens were more likely to enter simple patches and openings during winter, when deep snow was present. Because marten patch use differed during winter, I concluded that researchers should use caution when using seasonally collected data to create year-round habitat models. Overall, movement was most limited during summer when predation risk likely deterred martens from moving through simple patches and openings. In Chapter 3, I quantified habitat selection and marten behavior using fine-scale movement data. I evaluated movement-based habitat selection at two scales: (1) selection of home ranges within landscapes and (2) selection of patches within the home ranges. I characterized marten movement patterns and tested whether variance, speed, and sinuosity of movements differed by patch, sex, and season. Martens selected home ranges with fewer openings than available in the landscape, and selected complex patches over simple patches and openings within their home range. On average, martens moved approximately 7 km per day and greater than 1 km per hour – which is notably high for a 600-1000g mammal. Martens moved more slowly, consistently, and sinuously in complex patches. In openings, martens traveled linearly with greater variance in their speed. In simple patches, movement generally was linear and rapid with some variation. I hypothesized that martens used complex patches for foraging and acquisition of resources, traveled through simple patches with the potential for infrequent foraging bouts, and very infrequently crossed openings. Although I found some differences in movement behavior between sexes and seasons, behavior was generally consistent for both sexes in different patch types. I provide general conclusions in Chapter 4 and discuss considerations for future research and management. Title: Habitat use and movement behavior of Pacific marten (Martes caurina) in response to forest management practices in Lassen National Forest, California Author: Moriarty, Katie M. Some of the most pressing conservation concerns involve declining populations of species with low fecundity and highly specialized foraging and reproductive requirements. Yet, we often lack a functional understanding of how individuals of those species interact with their environment, specifically how their movement is affected by human-induced changes. In order to maintain connectivity and viable populations, public land managers require science to inform how changes in structure affect the individual movements and thus population connectivity of sensitive species. I collected detailed movement data on Pacific martens (Martes caurina) in Lassen National Forest, California, during 2010-2013. Martens are small carnivores that are closely associated with old forest elements (e.g., large snags and logs). Marten populations rapidly decline with loss and fragmentation of forest cover. As such, martens are a U.S. Forest Service Management Indicator Species and a Species of Special Concern in the state of California. My goal was to understand martens' behavior in forest patches that were altered by thinning to remove ladder fuels-small diameter trees, understory vegetation, and branches near the ground. Such fuels treatments are increasingly prevalent on public lands, especially in dry forests, to reduce risk of high-severity and high-intensity fire. Although previous research suggested martens selection for dense forest and avoid gaps in forest cover, no information was available describing martens' use of simplified thinned patches. The objectives of my dissertation were to: (1) test whether marten movement and activity could accurately be measured using miniature GPS collars, and (2) evaluate marten use, selection, and behavior in patches that differed in structural complexity. Global positioning system (GPS) telemetry provides opportunities to collect detailed information from free-ranging animals with a high degree of precision and accuracy. Miniature GPS collars (42-60g) have only been available since 2009 for mammals and have not been consistently effective. Furthermore, all GPS units suffer from non-random data loss and location error, which is often exacerbated by dense vegetation. Given these constraints, it was questionable whether GPS collars would be an effective tool for studying martens. In Chapter 1, I evaluated how satellite data and environmental conditions affected performance of GPS units. I used a paired experimental design and programmed the GPS unit to retain or remove satellite data before attempting a location (fix). I found that short intervals between fix attempts significantly increased the likelihood of fix success. Locations estimated using at least 4 satellites were, on average, within 28 m of the actual location regardless of vegetation cover. Thus, location estimates at short intervals with >4 satellites were not typically biased by dense vegetation. Accurate fine-scale information on martens was necessary to quantify and interpret patch use and habitat selection. I evaluated martens’ use and behavior in three forest patch types that differed in structural complexity (complex, simple, and open). In Chapter 2, I quantified use patch use in two seasons–summer and winter. I used food-titration experiments to standardize motivation of martens to enter different patch types and compared these short-term incentivized experiments with year-round observational telemetry data (GPS and very high frequency telemetry). Martens selected complex patches and avoided both simple patches and openings, but not equivalently–openings were strongly avoided. With baited incentive, martens were more likely to enter simple patches and openings during winter, when deep snow was present. Because marten patch use differed during winter, I concluded that researchers should use caution when using seasonally collected data to create year-round habitat models. Overall, movement was most limited during summer when predation risk likely deterred martens from moving through simple patches and openings. In Chapter 3, I quantified habitat selection and marten behavior using fine-scale movement data. I evaluated movement-based habitat selection at two scales: (1) selection of home ranges within landscapes and (2) selection of patches within the home ranges. I characterized marten movement patterns and tested whether variance, speed, and sinuosity of movements differed by patch, sex, and season. Martens selected home ranges with fewer openings than available in the landscape, and selected complex patches over simple patches and openings within their home range. On average, martens moved approximately 7 km per day and greater than 1 km per hour – which is notably high for a 600-1000g mammal. Martens moved more slowly, consistently, and sinuously in complex patches. In openings, martens traveled linearly with greater variance in their speed. In simple patches, movement generally was linear and rapid with some variation. I hypothesized that martens used complex patches for foraging and acquisition of resources, traveled through simple patches with the potential for infrequent foraging bouts, and very infrequently crossed openings. Although I found some differences in movement behavior between sexes and seasons, behavior was generally consistent for both sexes in different patch types. I provide general conclusions in Chapter 4 and discuss considerations for future research and management. Close

• 73. [Article] Species Diversification in Aquaculture: a Global Assessment

  Suggested Bibliographic Reference: Challenging New Frontiers in the Global Seafood Sector: Proceedings of the Eighteenth Biennial Conference of the International Institute of Fisheries Economics and Trade, ...

  Citation × Citation Citation Abstract Copy Title: Species Diversification in Aquaculture: a Global Assessment Author: Zhou, Xiaowei, Yan, Xue, Cai, Junning Year: 2016 Suggested Bibliographic Reference: Challenging New Frontiers in the Global Seafood Sector: Proceedings of the Eighteenth Biennial Conference of the International Institute of Fisheries Economics and Trade, July 11-15, 2016. Compiled by Stefani J. Evers and Ann L. Shriver. International Institute of Fisheries Economics and Trade (IIFET), Corvallis, 2016. Title: Species Diversification in Aquaculture: a Global Assessment Author: Zhou, Xiaowei, Yan, Xue, Cai, Junning Year: 2016 Suggested Bibliographic Reference: Challenging New Frontiers in the Global Seafood Sector: Proceedings of the Eighteenth Biennial Conference of the International Institute of Fisheries Economics and Trade, July 11-15, 2016. Compiled by Stefani J. Evers and Ann L. Shriver. International Institute of Fisheries Economics and Trade (IIFET), Corvallis, 2016. Close

• 74. [Article] Geographic variation in Dunn's salamander Plethodon dunni Bishop (Amphibia:Caudata:Plethodontidae)

  Life history attributes and apparent distributional patterns suggest that Plethodon dunni exists as small, semi-isolated populations throughout its range. Isozyme and morphological variation in this species ...

  Citation × Citation Citation Abstract Copy Title: Geographic variation in Dunn's salamander Plethodon dunni Bishop (Amphibia:Caudata:Plethodontidae) Author: Hanlin, Hugh Grady Life history attributes and apparent distributional patterns suggest that Plethodon dunni exists as small, semi-isolated populations throughout its range. Isozyme and morphological variation in this species was examined to determine any possible geographic trends. Starch gel electrophoresis was utilized to examine genetic variation at 24 isozyme loci in 287 individuals from 12 populations to determine the genetic structure of populations of this species. Low total genetic variability was observed. However, this variability is partitioned into relatively low genetic heterozygosity within populations and proportionally high diversity between populations. It is concluded that this geographically restricted species is characterized by small local populations with little gene flow. Comparisons with previous reports of Plethodon species indicate that the high genetic divergence between local populations is apparently general for species in this genus. There is marked reduction in heterozygosity with peripheral populations of P. dunni, which may result from the reduction in genetic exchange from surrounding populations in peripheral as ccmpared to central populations. No indication of additional structural genes associated with the increased DNA in P. dunni was found. Morphological variation in 10 populations was examined via stepwise discriminant analyses. Considerable overlap of individuals' canonical scores and only moderately correct classifications into groups indicate that phenotypic expression in this species is exceedingly similar. However, on a fine scale there is significant heterogeneity between all populations. Generalized distance values (D²) between the P. dunni populations are high, particularly when compared to those of Aneides ferreus, a wider-ranging, more ubiquitous sympatric species. Clinal variation in morphological divergence was observed and was highly correlated with a similar cline in allele frequencies of EST-2. It is concluded that the phenotypic structuring of populations of P. dunni is consistent with the structuring observed via electrophoresis and that this species is characterized by small, localized populations throughout its range. Title: Geographic variation in Dunn's salamander Plethodon dunni Bishop (Amphibia:Caudata:Plethodontidae) Author: Hanlin, Hugh Grady Life history attributes and apparent distributional patterns suggest that Plethodon dunni exists as small, semi-isolated populations throughout its range. Isozyme and morphological variation in this species was examined to determine any possible geographic trends. Starch gel electrophoresis was utilized to examine genetic variation at 24 isozyme loci in 287 individuals from 12 populations to determine the genetic structure of populations of this species. Low total genetic variability was observed. However, this variability is partitioned into relatively low genetic heterozygosity within populations and proportionally high diversity between populations. It is concluded that this geographically restricted species is characterized by small local populations with little gene flow. Comparisons with previous reports of Plethodon species indicate that the high genetic divergence between local populations is apparently general for species in this genus. There is marked reduction in heterozygosity with peripheral populations of P. dunni, which may result from the reduction in genetic exchange from surrounding populations in peripheral as ccmpared to central populations. No indication of additional structural genes associated with the increased DNA in P. dunni was found. Morphological variation in 10 populations was examined via stepwise discriminant analyses. Considerable overlap of individuals' canonical scores and only moderately correct classifications into groups indicate that phenotypic expression in this species is exceedingly similar. However, on a fine scale there is significant heterogeneity between all populations. Generalized distance values (D²) between the P. dunni populations are high, particularly when compared to those of Aneides ferreus, a wider-ranging, more ubiquitous sympatric species. Clinal variation in morphological divergence was observed and was highly correlated with a similar cline in allele frequencies of EST-2. It is concluded that the phenotypic structuring of populations of P. dunni is consistent with the structuring observed via electrophoresis and that this species is characterized by small, localized populations throughout its range. Close

• 75. [Article] Age, growth and maturity of the longnose skate (Raja rhina) for the U.S. west coast and sensitivity to fishing impacts

  In the past, sharks, skates and ray species have mainly occurred in incidental fisheries. Now they are increasingly being directly targeted due to the depleted status of traditionally targeted species. ...

  Citation × Citation Citation Abstract Copy Title: Age, growth and maturity of the longnose skate (Raja rhina) for the U.S. west coast and sensitivity to fishing impacts Author: Thompson, Josie E. In the past, sharks, skates and ray species have mainly occurred in incidental fisheries. Now they are increasingly being directly targeted due to the depleted status of traditionally targeted species. The life history characteristics of many elasmobranch species make them more sensitive to high rates of fishing mortality. The combination of these factors has resulted in the known local depletion of several elasmobranch species; including the barndoor skate, Raja laevis, of the Northwest Atlantic and the common skate, Raja batis, of Irish Sea. The longnose skate, Raja rhina, occurs commonly as incidental catch in trawl fisheries off the coast of California, Oregon and Washington. Commercial landings of skates, including R. rhina, have increased dramatically along the U.S. West coast. The objectives of this study have been to calculate accurate growth and maturity parameters for Raja rhina in order that the vulnerability of this species to fishing mortality can be assessed. The slow growth rates (k=0.04 to 0.06) and late ages-at-50% maturity (11 to 16 years with maximum ages between 15 and 22 years, depending on sex and region) which were calculated indicate that this species may be at great risk of depletion in the future. Survey biomass trends indicate that R. rhina populations have remained stable over the past twenty years. However, the possibility that biomass levels in the distant past were much higher than they are at present cannot be ruled out. It is recommended that the collection of fishery-dependent data for this species and other skate species begins immediately. This information, along with the results found in this are needed for a proper assessment for Raja rhina, so that the effects of current fishing pressures can be evaluated and regulated appropriately. Title: Age, growth and maturity of the longnose skate (Raja rhina) for the U.S. west coast and sensitivity to fishing impacts Author: Thompson, Josie E. In the past, sharks, skates and ray species have mainly occurred in incidental fisheries. Now they are increasingly being directly targeted due to the depleted status of traditionally targeted species. The life history characteristics of many elasmobranch species make them more sensitive to high rates of fishing mortality. The combination of these factors has resulted in the known local depletion of several elasmobranch species; including the barndoor skate, Raja laevis, of the Northwest Atlantic and the common skate, Raja batis, of Irish Sea. The longnose skate, Raja rhina, occurs commonly as incidental catch in trawl fisheries off the coast of California, Oregon and Washington. Commercial landings of skates, including R. rhina, have increased dramatically along the U.S. West coast. The objectives of this study have been to calculate accurate growth and maturity parameters for Raja rhina in order that the vulnerability of this species to fishing mortality can be assessed. The slow growth rates (k=0.04 to 0.06) and late ages-at-50% maturity (11 to 16 years with maximum ages between 15 and 22 years, depending on sex and region) which were calculated indicate that this species may be at great risk of depletion in the future. Survey biomass trends indicate that R. rhina populations have remained stable over the past twenty years. However, the possibility that biomass levels in the distant past were much higher than they are at present cannot be ruled out. It is recommended that the collection of fishery-dependent data for this species and other skate species begins immediately. This information, along with the results found in this are needed for a proper assessment for Raja rhina, so that the effects of current fishing pressures can be evaluated and regulated appropriately. Close

• 76. [Article] The morphology and taxonomic significance of the male genitalia of Coenonycha (Coleoptera, Scarabaeidae)

  The genus Coenonycha contains 30 described species of small to medium sized scarabs. They are found in the arid and semi-arid regions of western United States and northern Baja California. The adults feed ...

  Citation × Citation Citation Abstract Copy Title: The morphology and taxonomic significance of the male genitalia of Coenonycha (Coleoptera, Scarabaeidae) Author: Davidson, Jean Hoyt Puckle The genus Coenonycha contains 30 described species of small to medium sized scarabs. They are found in the arid and semi-arid regions of western United States and northern Baja California. The adults feed at night on several genera of xerophylous plants. An examination of the male genitalia of the 19 long-winged species indicates that the internal sac possesses characters which are stable within a species and are, therefore, taxonomically useful. These structures are a dorsal, toothed, knob-like sclerite and from one to four spinose fields on the enlarged portion of the sac. Variation in these structures within a species occurs in the number of teeth on the knob and spines in the fields. Sixteen new species of Coenonycha were discovered in the course of this study. They are indicated by letter in the text and phenetic tree and will be described elsewhere. The male genitalic structures of the 19 long-winged species are described in detail and illustrated. A key to these species, using primarily the basal knob and spinose fields is included. In addition, a key (modified from Cazier and Mc Clay, 1943) to all the described species of Coenonycha, using characters such as color, pilosity, clypeal reflection and pronatal punctation is provided. A key to the North American genera of Macrodacylini using the parameres, basal piece, basal apodeme, genital segment, and internal sac shows the diversity of genitalic structures in the tribe. Coenonycha, Dichelonyx, and Gymnopyge are presently placed with Macrodactylus and Isonychus in the Macrodactylini. Based on genitalic, larval, spiracular, and adult external morphological structures, Coenonycha, Dichelonyx, and Gymnopyge should be separated from the Macrodactylini and placed in the tribe Dichelonychini. Title: The morphology and taxonomic significance of the male genitalia of Coenonycha (Coleoptera, Scarabaeidae) Author: Davidson, Jean Hoyt Puckle The genus Coenonycha contains 30 described species of small to medium sized scarabs. They are found in the arid and semi-arid regions of western United States and northern Baja California. The adults feed at night on several genera of xerophylous plants. An examination of the male genitalia of the 19 long-winged species indicates that the internal sac possesses characters which are stable within a species and are, therefore, taxonomically useful. These structures are a dorsal, toothed, knob-like sclerite and from one to four spinose fields on the enlarged portion of the sac. Variation in these structures within a species occurs in the number of teeth on the knob and spines in the fields. Sixteen new species of Coenonycha were discovered in the course of this study. They are indicated by letter in the text and phenetic tree and will be described elsewhere. The male genitalic structures of the 19 long-winged species are described in detail and illustrated. A key to these species, using primarily the basal knob and spinose fields is included. In addition, a key (modified from Cazier and Mc Clay, 1943) to all the described species of Coenonycha, using characters such as color, pilosity, clypeal reflection and pronatal punctation is provided. A key to the North American genera of Macrodacylini using the parameres, basal piece, basal apodeme, genital segment, and internal sac shows the diversity of genitalic structures in the tribe. Coenonycha, Dichelonyx, and Gymnopyge are presently placed with Macrodactylus and Isonychus in the Macrodactylini. Based on genitalic, larval, spiracular, and adult external morphological structures, Coenonycha, Dichelonyx, and Gymnopyge should be separated from the Macrodactylini and placed in the tribe Dichelonychini. Close

• 77. [Article] Behavior of Nine Species of Pacific Rockfish after Hook-and-Line Capture, Recompression, and Release

  We evaluated the effect of barotrauma on the behavior of nine species of Pacific rockfish Sebastes spp. after hook-and-line capture and release using a video-equipped underwater release cage. Sampling ...

  Citation × Citation Citation Abstract Copy Title: Behavior of Nine Species of Pacific Rockfish after Hook-and-Line Capture, Recompression, and Release Author: Hannah, Robert W., Matteson, Keith M. We evaluated the effect of barotrauma on the behavior of nine species of Pacific rockfish Sebastes spp. after hook-and-line capture and release using a video-equipped underwater release cage. Sampling was conducted across a range of bottom depths (12-194 m), mostly where barotrauma resulting from an expanded swim bladder and gaseous release of dissolved blood gases would be expected. Behavioral impairment from barotrauma was depth related but highly species specific. Increased depth of capture was associated with lower behavioral scores for black rockfish S. melanops, blue rockfish S. mystinus, and yelloweye rockfish S. ruberrimus, but not for canary rockfish S. pinniger. Behaviorally impaired fish showed a decreased ability to maintain vertical orientation and were slower in exiting the release cage. Species differed in the degree of behavioral impairment resulting from barotrauma and in how rapidly behavioral impairment increased with depth of capture. When captured at depths between 40 and 99 m, blue rockfish showed the most serious behavioral impairment, 8 of 18 (44%) failing to swim away at the time of release and simply drifting off in a sideways or upside-down posture. In the same depth range all of the other species sampled showed only moderate behavioral impairment, which is indicative of some potential for survival after discard by the fishery. Surface observations of the external signs of barotrauma were variable among species and were poor indicators of which species would show behavioral impairment upon release at depth. Within individual species, however, the external signs of barotrauma were associated with an increased probability of behavioral impairment at time of release. Title: Behavior of Nine Species of Pacific Rockfish after Hook-and-Line Capture, Recompression, and Release Author: Hannah, Robert W., Matteson, Keith M. We evaluated the effect of barotrauma on the behavior of nine species of Pacific rockfish Sebastes spp. after hook-and-line capture and release using a video-equipped underwater release cage. Sampling was conducted across a range of bottom depths (12-194 m), mostly where barotrauma resulting from an expanded swim bladder and gaseous release of dissolved blood gases would be expected. Behavioral impairment from barotrauma was depth related but highly species specific. Increased depth of capture was associated with lower behavioral scores for black rockfish S. melanops, blue rockfish S. mystinus, and yelloweye rockfish S. ruberrimus, but not for canary rockfish S. pinniger. Behaviorally impaired fish showed a decreased ability to maintain vertical orientation and were slower in exiting the release cage. Species differed in the degree of behavioral impairment resulting from barotrauma and in how rapidly behavioral impairment increased with depth of capture. When captured at depths between 40 and 99 m, blue rockfish showed the most serious behavioral impairment, 8 of 18 (44%) failing to swim away at the time of release and simply drifting off in a sideways or upside-down posture. In the same depth range all of the other species sampled showed only moderate behavioral impairment, which is indicative of some potential for survival after discard by the fishery. Surface observations of the external signs of barotrauma were variable among species and were poor indicators of which species would show behavioral impairment upon release at depth. Within individual species, however, the external signs of barotrauma were associated with an increased probability of behavioral impairment at time of release. Close

• 78. [Article] Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by [publisher] ...

  Citation × Citation Citation Abstract Copy Title: Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings Author: Davis, Anne, Beck, Bryan R., Weiland, Jerry E. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by [publisher] and can be found at: https://www.apsnet.org/publications/Pages/default.aspx. Title: Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings Author: Davis, Anne, Beck, Bryan R., Weiland, Jerry E. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by [publisher] and can be found at: https://www.apsnet.org/publications/Pages/default.aspx. Close

• 79. [Article] Resveratrol Influence on Lifespan among Caenorhabditis Elegans Genetic Variants & Implications for Personalized Medicine

  46 pages. A thesis presented to the Department of Human Physiology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, ...

  Citation × Citation Citation Abstract Copy Title: Resveratrol Influence on Lifespan among Caenorhabditis Elegans Genetic Variants & Implications for Personalized Medicine Author: Caul, Tela Amber Year: 2017 46 pages. A thesis presented to the Department of Human Physiology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017 Title: Resveratrol Influence on Lifespan among Caenorhabditis Elegans Genetic Variants & Implications for Personalized Medicine Author: Caul, Tela Amber Year: 2017 46 pages. A thesis presented to the Department of Human Physiology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017 Close

• 80. [Article] Plant community dynamics in remnant and restored Willamette Valley wetland prairies

  Invasion by exotic species can pose a major challenge for developing native plant communities in wetland restoration projects. Often native plant communities do not develop as anticipated in restored wetlands ...

  Citation × Citation Citation Abstract Copy Title: Plant community dynamics in remnant and restored Willamette Valley wetland prairies Author: Schwindt, Rachel A. Invasion by exotic species can pose a major challenge for developing native plant communities in wetland restoration projects. Often native plant communities do not develop as anticipated in restored wetlands due to colonization by exotic species that dominate the native plant community. Despite the time and expense to restore wetlands, there has been little long term research to compare plant communities in restored and natural wetland sites. Research into plant community diversity across several wetland sites over several years can provide a broader perspective into how these ecosystems recover from long-term disturbance. The objective of this study was to compare plant community change from 2000 to 2005 between restored and remnant wetland prairie sites in the southern Willamette Valley in Oregon to determine if exotic species abundance was consistent between these groups. Specific objectives included 1) comparing the diversity and abundance of all species in remnant and restored wetland prairie sites, 2) evaluate the trajectory of community change between remnant and restored wetland prairie sites to determine if there was rapid change in restored sites, and 3) describe the plot level heterogeneity of the plant community in all sites to determine how microsites influence diversity. In 2005, species abundance was re-measured in four remnant wetland prairies and four restored wetland prairies that had been selected for an unrelated vegetation survey in 2000. Species were characterized by life form, origin, and wetland indicator status. Species abundance between groups of remnant and restored sites were compared using a multi-response permutation procedure (MRPP). The plant community trajectory was evaluated with nonmetric multidimensional scaling (NMS) and tested for significance with multivariate analysis of variance (MANOVA). Species area curves were compared between sites and within remnant and restored groups of plots. Within-year and between-year significance tests indicated that remnant and restored sites were similar in exotic species abundance, graminoid abundance, and wetland species abundance with no significant difference between these remnant and restored wetland prairie sites. Individual sites in both groups experienced changes in exotic species abundance which confounded the statistical results. Species heterogeneity was no more spatially diverse across the remnant site plots than restored site plots. Species area curves did not show significant differences between remnant and restored plots but individual plots did show homogeneous community characteristics at smaller spatial scales. Restoration sites had developed high graminoid cover by the 2000 survey which was conducted two to three years after restoration was initiated. All sites were equally likely to contain exotic species. Exotic species common across all sites included Centaurium umbellatum, Holcus lanatus, and Hypericum perforatum. Native species common across sites included Deschampsia cespitosa, Danthonia californica and Juncus tenuis. These results suggested that differences between remnant and restored Willamette Valley wetland prairie sites were not generalizable at the landscape scale and were more dependent on site specific management activities and local barriers to colonization. Five years may not be enough time to see evidence that suggests if restored plant communities will develop spatial characteristics of the remnant sites. This research does suggest that multi-site comparisons help distinguish individual sites that are not developing characteristics of remnant wetland plant communities. Title: Plant community dynamics in remnant and restored Willamette Valley wetland prairies Author: Schwindt, Rachel A. Invasion by exotic species can pose a major challenge for developing native plant communities in wetland restoration projects. Often native plant communities do not develop as anticipated in restored wetlands due to colonization by exotic species that dominate the native plant community. Despite the time and expense to restore wetlands, there has been little long term research to compare plant communities in restored and natural wetland sites. Research into plant community diversity across several wetland sites over several years can provide a broader perspective into how these ecosystems recover from long-term disturbance. The objective of this study was to compare plant community change from 2000 to 2005 between restored and remnant wetland prairie sites in the southern Willamette Valley in Oregon to determine if exotic species abundance was consistent between these groups. Specific objectives included 1) comparing the diversity and abundance of all species in remnant and restored wetland prairie sites, 2) evaluate the trajectory of community change between remnant and restored wetland prairie sites to determine if there was rapid change in restored sites, and 3) describe the plot level heterogeneity of the plant community in all sites to determine how microsites influence diversity. In 2005, species abundance was re-measured in four remnant wetland prairies and four restored wetland prairies that had been selected for an unrelated vegetation survey in 2000. Species were characterized by life form, origin, and wetland indicator status. Species abundance between groups of remnant and restored sites were compared using a multi-response permutation procedure (MRPP). The plant community trajectory was evaluated with nonmetric multidimensional scaling (NMS) and tested for significance with multivariate analysis of variance (MANOVA). Species area curves were compared between sites and within remnant and restored groups of plots. Within-year and between-year significance tests indicated that remnant and restored sites were similar in exotic species abundance, graminoid abundance, and wetland species abundance with no significant difference between these remnant and restored wetland prairie sites. Individual sites in both groups experienced changes in exotic species abundance which confounded the statistical results. Species heterogeneity was no more spatially diverse across the remnant site plots than restored site plots. Species area curves did not show significant differences between remnant and restored plots but individual plots did show homogeneous community characteristics at smaller spatial scales. Restoration sites had developed high graminoid cover by the 2000 survey which was conducted two to three years after restoration was initiated. All sites were equally likely to contain exotic species. Exotic species common across all sites included Centaurium umbellatum, Holcus lanatus, and Hypericum perforatum. Native species common across sites included Deschampsia cespitosa, Danthonia californica and Juncus tenuis. These results suggested that differences between remnant and restored Willamette Valley wetland prairie sites were not generalizable at the landscape scale and were more dependent on site specific management activities and local barriers to colonization. Five years may not be enough time to see evidence that suggests if restored plant communities will develop spatial characteristics of the remnant sites. This research does suggest that multi-site comparisons help distinguish individual sites that are not developing characteristics of remnant wetland plant communities. Close

• 81. [Article] Characterizing early-seral competitive mechanisms influencing Douglas-fir seedling growth, vegetation community development, and physiology of selected weedy plant species

  Three studies were conducted to characterize and present early-seral competition between Douglas-fir seedlings and the surrounding vegetation communities during Pacific Northwest forest establishment. ...

  Citation × Citation Citation Abstract Copy Title: Characterizing early-seral competitive mechanisms influencing Douglas-fir seedling growth, vegetation community development, and physiology of selected weedy plant species Author: Dinger, Eric J. Three studies were conducted to characterize and present early-seral competition between Douglas-fir seedlings and the surrounding vegetation communities during Pacific Northwest forest establishment. The first experiment served as the foundation for this dissertation and was designed to quantify tradeoffs associated with delaying forest establishment activities by introducing a fallow year in order to provide longer-term management of competing vegetation. A range of six operationally relevant treatments were applied over two growing seasons that included in the first (1) a no-action control, (2) a spring release only, (3) a fall site preparation without sulfometuron methyl followed by a spring release, as well as (4) a fall site preparation with sulfometuron methyl and a spring release. In the second year, there was (5) a fall site preparation without sulfometuron methyl followed by a spring release and also in the second year (6) a fall site preparation with sulfometuron methyl and a spring release. Treatments 5 and 6 were left fallow without planting during the first year. These treatments were applied in two replicated experiments within the Oregon Coast Range. After adjusting for initial seedling size, year-3 results indicated that plantation establishment and competition control immediately after harvest (i.e. no fallow period) enabled seedlings to be physically larger than those planted after a one year delay. At the Boot study site, limiting vegetation below 20% for the first growing season improved year-3 Douglas-fir seedling stem volume over 273 cm³. Delaying establishment activities one year and reducing competing vegetation below 11% enabled seedling volume after two years to be statistically the same as three year old seedlings in the no-action control, a volume range of between 148 to 166 cm³. Delaying forest establishment at Jackson Mast improved seedling survivorship over 88% when a spring heat event reduced survivorship of trees planted a year earlier to less than 69%. The combined effect of applying a fall site preparation and spring release was necessary to reduce competitive cover below 10% in the year following treatment and provided longer-lasting control of woody/semi-woody plants. Less intense control measures (i.e. no-action control and treatment 2) were not able to restrain woody/semi-woody plant cover which grew to nearly 40% at Boot and over 24% at Jackson Mast in three years. No treatment regime provided multi-year control of herbaceous species. Including sulfometuron methyl in the fall site preparation tank-mix did not have a negative effect on seedling growth or provide significant reductions in plant community abundance in the year following application when compared to similar regimes that did not include the chemical. Delaying establishment lengthened the amount of time associated with forest regeneration except on a site that accentuated a spring heat event. In the second study, horizontal distance and azimuth readings provided by a ground-based laser were used to stem map seedling locations and experimental unit features at Boot. These data were used to create a relative Cartesian coordinate system that defined spatially explicit polygons enabling, for the first time, the ability to collect positional data on competing forest vegetation within an entire experimental unit. Deemed "vixels" or vegetation pixels, these polygons were assessed for measures of total cover and cover of the top three most abundance species during the initial three years of establishment. An alternate validity check of research protocols was provided when total cover resulting from this vixel technique was compared to a more traditional survey of four randomly located subplots. The resulting linear regression equation had an adjusted R² of 0.90 between these two techniques of assessing total cover. When compared within a treatment and year, total cover differed by less than 12 percentage points between the two techniques. Analysis of year-3 woody/semi-woody plant cover produced by the techniques led to identical treatment differences. Two treatments resulted in woody/semi-woody cover of approximately 1500 ft² by the vixel method and nearly 40% cover by the subplot method while the remaining four treatments were grouped below 600 ft² or 20% cover, respectively. With continued refinement, these techniques could visually present forest development through all phases and provide long-term information used to bolster growth and yield models, measures of site productivity, as well as community ecology research. The third study evaluated the season-long gas exchange and biomass partitioning of four weedy plant species capable of rapidly colonizing Pacific Northwest regenerating forests. Cirsium arvense, Cirsium vulgare, Rubus ursinus and Senecio sylvaticus were studied at two sites. A greenhouse was used to introduce two levels of irrigation (well-watered and droughty). These species were also studied while growing among a larger vegetation community at a field site. Irrigation treatments had little impact on gas exchange rates. Species achieved maximum photosynthetic rates of 30, 20, 15 and 25 μmol CO₂ m⁻² s⁻¹ (respectively) prior to mid-July coinciding with an active phase of vegetative growth. As the season progressed, photosynthetic rates declined in spite of well-watered conditions while transpiration rates remained relatively consistent even when soil water decreased below 0.25 m³ H₂O/m³ soil. Water use efficiency was high until late-July for all study species, after which time it decreased below 5 μmol CO₂ · mmol H₂O⁻¹. Multi-leaf gas exchange measurements as well as biomass data provided a holistic view of plantlevel mechanisms used to shunt activity toward developing tissues. Herbaceous species had assimilation rates that differed vertically (within each species) by as much as 10 to 20 μmol CO₂ m⁻² s⁻¹ from July to September as lower leaves senesced in favor of those higher on study plants. Specific leaf area was greatest in June for all species then declined indicating species placed little effort into sacrificial early season leaves when compared to those higher on the plant that could continue to support flowering or vegetative growth. The study of seasonal gas exchange in the presence of declining water availability has helped to describe competitive mechanisms at work during forest regeneration as well as provide physiologic support for the application of vegetation management regimes. Title: Characterizing early-seral competitive mechanisms influencing Douglas-fir seedling growth, vegetation community development, and physiology of selected weedy plant species Author: Dinger, Eric J. Three studies were conducted to characterize and present early-seral competition between Douglas-fir seedlings and the surrounding vegetation communities during Pacific Northwest forest establishment. The first experiment served as the foundation for this dissertation and was designed to quantify tradeoffs associated with delaying forest establishment activities by introducing a fallow year in order to provide longer-term management of competing vegetation. A range of six operationally relevant treatments were applied over two growing seasons that included in the first (1) a no-action control, (2) a spring release only, (3) a fall site preparation without sulfometuron methyl followed by a spring release, as well as (4) a fall site preparation with sulfometuron methyl and a spring release. In the second year, there was (5) a fall site preparation without sulfometuron methyl followed by a spring release and also in the second year (6) a fall site preparation with sulfometuron methyl and a spring release. Treatments 5 and 6 were left fallow without planting during the first year. These treatments were applied in two replicated experiments within the Oregon Coast Range. After adjusting for initial seedling size, year-3 results indicated that plantation establishment and competition control immediately after harvest (i.e. no fallow period) enabled seedlings to be physically larger than those planted after a one year delay. At the Boot study site, limiting vegetation below 20% for the first growing season improved year-3 Douglas-fir seedling stem volume over 273 cm³. Delaying establishment activities one year and reducing competing vegetation below 11% enabled seedling volume after two years to be statistically the same as three year old seedlings in the no-action control, a volume range of between 148 to 166 cm³. Delaying forest establishment at Jackson Mast improved seedling survivorship over 88% when a spring heat event reduced survivorship of trees planted a year earlier to less than 69%. The combined effect of applying a fall site preparation and spring release was necessary to reduce competitive cover below 10% in the year following treatment and provided longer-lasting control of woody/semi-woody plants. Less intense control measures (i.e. no-action control and treatment 2) were not able to restrain woody/semi-woody plant cover which grew to nearly 40% at Boot and over 24% at Jackson Mast in three years. No treatment regime provided multi-year control of herbaceous species. Including sulfometuron methyl in the fall site preparation tank-mix did not have a negative effect on seedling growth or provide significant reductions in plant community abundance in the year following application when compared to similar regimes that did not include the chemical. Delaying establishment lengthened the amount of time associated with forest regeneration except on a site that accentuated a spring heat event. In the second study, horizontal distance and azimuth readings provided by a ground-based laser were used to stem map seedling locations and experimental unit features at Boot. These data were used to create a relative Cartesian coordinate system that defined spatially explicit polygons enabling, for the first time, the ability to collect positional data on competing forest vegetation within an entire experimental unit. Deemed "vixels" or vegetation pixels, these polygons were assessed for measures of total cover and cover of the top three most abundance species during the initial three years of establishment. An alternate validity check of research protocols was provided when total cover resulting from this vixel technique was compared to a more traditional survey of four randomly located subplots. The resulting linear regression equation had an adjusted R² of 0.90 between these two techniques of assessing total cover. When compared within a treatment and year, total cover differed by less than 12 percentage points between the two techniques. Analysis of year-3 woody/semi-woody plant cover produced by the techniques led to identical treatment differences. Two treatments resulted in woody/semi-woody cover of approximately 1500 ft² by the vixel method and nearly 40% cover by the subplot method while the remaining four treatments were grouped below 600 ft² or 20% cover, respectively. With continued refinement, these techniques could visually present forest development through all phases and provide long-term information used to bolster growth and yield models, measures of site productivity, as well as community ecology research. The third study evaluated the season-long gas exchange and biomass partitioning of four weedy plant species capable of rapidly colonizing Pacific Northwest regenerating forests. Cirsium arvense, Cirsium vulgare, Rubus ursinus and Senecio sylvaticus were studied at two sites. A greenhouse was used to introduce two levels of irrigation (well-watered and droughty). These species were also studied while growing among a larger vegetation community at a field site. Irrigation treatments had little impact on gas exchange rates. Species achieved maximum photosynthetic rates of 30, 20, 15 and 25 μmol CO₂ m⁻² s⁻¹ (respectively) prior to mid-July coinciding with an active phase of vegetative growth. As the season progressed, photosynthetic rates declined in spite of well-watered conditions while transpiration rates remained relatively consistent even when soil water decreased below 0.25 m³ H₂O/m³ soil. Water use efficiency was high until late-July for all study species, after which time it decreased below 5 μmol CO₂ · mmol H₂O⁻¹. Multi-leaf gas exchange measurements as well as biomass data provided a holistic view of plantlevel mechanisms used to shunt activity toward developing tissues. Herbaceous species had assimilation rates that differed vertically (within each species) by as much as 10 to 20 μmol CO₂ m⁻² s⁻¹ from July to September as lower leaves senesced in favor of those higher on study plants. Specific leaf area was greatest in June for all species then declined indicating species placed little effort into sacrificial early season leaves when compared to those higher on the plant that could continue to support flowering or vegetative growth. The study of seasonal gas exchange in the presence of declining water availability has helped to describe competitive mechanisms at work during forest regeneration as well as provide physiologic support for the application of vegetation management regimes. Close

• 82. [Article] Release of dissolved organic matter by coastal diatoms

  Dissolved organic matter (DOM) production was examined in axenic batch cultures of five coastal diatom species. For Chaetoceros decipiens, dissolved organic carbon (DOC) accumulated beginning in late exponential growth ...

  Citation × Citation Citation Abstract Copy Title: Release of dissolved organic matter by coastal diatoms Author: Wheeler, Patricia A., Wetz, Michael S. Dissolved organic matter (DOM) production was examined in axenic batch cultures of five coastal diatom species. For Chaetoceros decipiens, dissolved organic carbon (DOC) accumulated beginning in late exponential growth as a result of increased cell density. For Cylindrotheca closterium, DOC actually decreased in late exponential growth and reached zero by the end of the experiment. This coincided with continued particulate organic carbon (POC) production and a threefold increase in the per-cell concentration of transparent exopolymer particles after nutrients were depleted. DOC release rates varied between species but were significantly higher for all five species in exponential or transition growth than during stationary growth. On average, 5% of the total fixed C was released as DOC for four of the diatoms, whereas C. decipiens released ,21% of its fixed C as DOC. The percentage of fixed C released as DOC varied little with nutrient availability or diatom growth stage. The DOM produced by some diatom species adheres to filters and is measured in the particulate organic matter (POM) fraction when cells are separated from the medium by filtration. This may be an important problem when diatom species with known benthic life histories are prevalent. In contrast, for species like Chaetoceros that have no benthic life history, DOM release rates estimated by bulk measurements or 14C appear to be accurate. Overall, these results indicate that the species composition of phytoplankton blooms has the potential to influence the relative importance of POM and DOM production and can complicate interpretation of those measurements. Title: Release of dissolved organic matter by coastal diatoms Author: Wheeler, Patricia A., Wetz, Michael S. Dissolved organic matter (DOM) production was examined in axenic batch cultures of five coastal diatom species. For Chaetoceros decipiens, dissolved organic carbon (DOC) accumulated beginning in late exponential growth as a result of increased cell density. For Cylindrotheca closterium, DOC actually decreased in late exponential growth and reached zero by the end of the experiment. This coincided with continued particulate organic carbon (POC) production and a threefold increase in the per-cell concentration of transparent exopolymer particles after nutrients were depleted. DOC release rates varied between species but were significantly higher for all five species in exponential or transition growth than during stationary growth. On average, 5% of the total fixed C was released as DOC for four of the diatoms, whereas C. decipiens released ,21% of its fixed C as DOC. The percentage of fixed C released as DOC varied little with nutrient availability or diatom growth stage. The DOM produced by some diatom species adheres to filters and is measured in the particulate organic matter (POM) fraction when cells are separated from the medium by filtration. This may be an important problem when diatom species with known benthic life histories are prevalent. In contrast, for species like Chaetoceros that have no benthic life history, DOM release rates estimated by bulk measurements or 14C appear to be accurate. Overall, these results indicate that the species composition of phytoplankton blooms has the potential to influence the relative importance of POM and DOM production and can complicate interpretation of those measurements. Close

• 83. [Article] Feeding ecology of juvenile rockfishes off Oregon and Washington based on stomach content and stable isotope analyses

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Springer ...

  Citation × Citation Citation Abstract Copy Title: Feeding ecology of juvenile rockfishes off Oregon and Washington based on stomach content and stable isotope analyses Author: Miller, Todd W., Van Gaest, Ahna, Bosley, Keith L., Bosley, Katelyn M., Elz, Anna, Brodeur, Richard D. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/227. Title: Feeding ecology of juvenile rockfishes off Oregon and Washington based on stomach content and stable isotope analyses Author: Miller, Todd W., Van Gaest, Ahna, Bosley, Keith L., Bosley, Katelyn M., Elz, Anna, Brodeur, Richard D. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/227. Close

• 84. [Article] Colonization and extinction in dynamic habitats: an occupancy approach for a Great Plains stream fish assemblage

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Ecological ...

  Citation × Citation Citation Abstract Copy Title: Colonization and extinction in dynamic habitats: an occupancy approach for a Great Plains stream fish assemblage Author: Falke, Jeffrey A., Bestgen, Kevin R., Bailey, Larissa L., Fausch, Kurt D. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://esa.org/. Title: Colonization and extinction in dynamic habitats: an occupancy approach for a Great Plains stream fish assemblage Author: Falke, Jeffrey A., Bestgen, Kevin R., Bailey, Larissa L., Fausch, Kurt D. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://esa.org/. Close

• 85. [Article] Physiological alterations following severe hypoxic stress in two species of fresh-water fish

  Bluegill sunfish, Lepomia macrochirus, and cutthroat trout, Salmo clarki, were exposed to a rapidly declining oxygen tension for a period of time sufficient to just cause loss of equilibrium in the fish. ...

  Citation × Citation Citation Abstract Copy Title: Physiological alterations following severe hypoxic stress in two species of fresh-water fish Author: Heath, Alan G. Bluegill sunfish, Lepomia macrochirus, and cutthroat trout, Salmo clarki, were exposed to a rapidly declining oxygen tension for a period of time sufficient to just cause loss of equilibrium in the fish. During recovery from the stress, measurements of oxygen uptake, blood lactic acid, blood glucose, liver glycogen, muscle glycogen, and hemoglobin or red blood cell counts were made at fixed intervals of time. Hypoxic stress caused an immediate rise in blood lactate and oxygen uptake in both species with the trout showing the greatest increases. This suggests a greater degree of oxygen debt in the latter, even though the stress routine used on this species was not as prolonged. A delayed peak in the blood lactate observed in the trout but not in the bluegill indicated a possible impairment of circulatory function in the former. The blood lactate returned to normal after two and five hours in the bluegill and cutthroat respectively. The return of the oxygen uptake to control levels required eight and ten hours respectively. An immediate mobilization of the carbohydrate stores occurred during the stress in both the bluegill and trout. The blood glucose concentration rose greatly in the bluegill but not in the trout. Mobilization of liver glycogen in the trout without a concomitant rise in glucose suggested utilization of the latter as rapidly as it was formed. During recovery from the hypoxic stress, resynthesis of glycogen stores occurred much more quickly in the bluegills than trout. Significant changes in hemoglobin or red blood cell numbers did not occur in either species indicating no change in blood water content, or effect on hemopoetic tissues resulting from the stress. It was concluded that the differences observed between these two species point to possible mechanisms in the bluegill which help it to tolerate acute hypoxic conditions better than the trout. Title: Physiological alterations following severe hypoxic stress in two species of fresh-water fish Author: Heath, Alan G. Bluegill sunfish, Lepomia macrochirus, and cutthroat trout, Salmo clarki, were exposed to a rapidly declining oxygen tension for a period of time sufficient to just cause loss of equilibrium in the fish. During recovery from the stress, measurements of oxygen uptake, blood lactic acid, blood glucose, liver glycogen, muscle glycogen, and hemoglobin or red blood cell counts were made at fixed intervals of time. Hypoxic stress caused an immediate rise in blood lactate and oxygen uptake in both species with the trout showing the greatest increases. This suggests a greater degree of oxygen debt in the latter, even though the stress routine used on this species was not as prolonged. A delayed peak in the blood lactate observed in the trout but not in the bluegill indicated a possible impairment of circulatory function in the former. The blood lactate returned to normal after two and five hours in the bluegill and cutthroat respectively. The return of the oxygen uptake to control levels required eight and ten hours respectively. An immediate mobilization of the carbohydrate stores occurred during the stress in both the bluegill and trout. The blood glucose concentration rose greatly in the bluegill but not in the trout. Mobilization of liver glycogen in the trout without a concomitant rise in glucose suggested utilization of the latter as rapidly as it was formed. During recovery from the hypoxic stress, resynthesis of glycogen stores occurred much more quickly in the bluegills than trout. Significant changes in hemoglobin or red blood cell numbers did not occur in either species indicating no change in blood water content, or effect on hemopoetic tissues resulting from the stress. It was concluded that the differences observed between these two species point to possible mechanisms in the bluegill which help it to tolerate acute hypoxic conditions better than the trout. Close

• 86. [Article] Social interaction between juvenile coho and fall chinook salmon in Sixes River, Oregon

  The nature of the interaction between juvenile coho salmon, Oncorhynchus kisutch (Walbaum), and fall chinook salmon, 0. tshawytscha (Walbaum), was studied in Sixes River, Oregon. Seining, snorkeling, and ...

  Citation × Citation Citation Abstract Copy Title: Social interaction between juvenile coho and fall chinook salmon in Sixes River, Oregon Author: Stein, Roy A. The nature of the interaction between juvenile coho salmon, Oncorhynchus kisutch (Walbaum), and fall chinook salmon, 0. tshawytscha (Walbaum), was studied in Sixes River, Oregon. Seining, snorkeling, and tagging were used to determine distribution and patterns of growth of these two species in the stream environment. Experiments conducted in flowing-water observation troughs that provided volitional residence were designed to examine the outcome of agonistic behavior between these two species. Both species were distributed throughout the entire river system in early spring. During this period, underwater surveys in the main river and selected tributaries indicated that both species preferred the same habitat. As temperatures increased during the late spring, coho disappeared from the main river, but continued to occupy cool tributaries. Fall chinook, on the other hand, were found primarily in the main river until early summer, when they moved to the estuary. Relatively few individuals remained in the tributaries. Experiments conducted in the troughs revealed that agonistic behavior, including nipping, chasing, lateral display, submission, and fleeing, occurred between juvenile coho and fall chinook. When the two species were together in the troughs and in cool tributary streams, coho grew faster than chinook. When isolated in troughs, both grew at similar rates. Coho tolerated fewer individuals per unit area than did chinook, and occupied positions of dominance near the source of incoming food at the upstream end of the troughs. Coho had brighter fin and body colors, greater fin development, deeper bodies, and were heavier than fall chinook of the same length. Coloration and morphology appeared to be important factors influencing the "apparent" size and presumably the social status of both species. Juvenile coho, with extensive development of fins and coloration and intense territorial behavior, are hypothesized to be adapted to small, cool tributary streams. Fall chinook, on the other hand, with conservative development of fins and coloration and related behavior patterns, appear to be adapted to conditions in the main river and estuary. Title: Social interaction between juvenile coho and fall chinook salmon in Sixes River, Oregon Author: Stein, Roy A. The nature of the interaction between juvenile coho salmon, Oncorhynchus kisutch (Walbaum), and fall chinook salmon, 0. tshawytscha (Walbaum), was studied in Sixes River, Oregon. Seining, snorkeling, and tagging were used to determine distribution and patterns of growth of these two species in the stream environment. Experiments conducted in flowing-water observation troughs that provided volitional residence were designed to examine the outcome of agonistic behavior between these two species. Both species were distributed throughout the entire river system in early spring. During this period, underwater surveys in the main river and selected tributaries indicated that both species preferred the same habitat. As temperatures increased during the late spring, coho disappeared from the main river, but continued to occupy cool tributaries. Fall chinook, on the other hand, were found primarily in the main river until early summer, when they moved to the estuary. Relatively few individuals remained in the tributaries. Experiments conducted in the troughs revealed that agonistic behavior, including nipping, chasing, lateral display, submission, and fleeing, occurred between juvenile coho and fall chinook. When the two species were together in the troughs and in cool tributary streams, coho grew faster than chinook. When isolated in troughs, both grew at similar rates. Coho tolerated fewer individuals per unit area than did chinook, and occupied positions of dominance near the source of incoming food at the upstream end of the troughs. Coho had brighter fin and body colors, greater fin development, deeper bodies, and were heavier than fall chinook of the same length. Coloration and morphology appeared to be important factors influencing the "apparent" size and presumably the social status of both species. Juvenile coho, with extensive development of fins and coloration and intense territorial behavior, are hypothesized to be adapted to small, cool tributary streams. Fall chinook, on the other hand, with conservative development of fins and coloration and related behavior patterns, appear to be adapted to conditions in the main river and estuary. Close

• 87. [Article] Community gradients of Arctic macrolichens in relation to succession, grazing and the environment

  The purpose of this dissertation was to define macrolichen community gradients in relation to succession, grazing and the environment. First, species scores indicating when macrolichen species appeared ...

  Citation × Citation Citation Abstract Copy Title: Community gradients of Arctic macrolichens in relation to succession, grazing and the environment Author: Holt, Emily A. The purpose of this dissertation was to define macrolichen community gradients in relation to succession, grazing and the environment. First, species scores indicating when macrolichen species appeared following disturbance were derived from the literature. Weighted averaging of these data with a community matrix created a successional score for each sample unit of interest. These scores are surrogates for community age for subsequent analyses. I then described lichen community structure and its relation to the environment in the Bering Land Bridge National Preserve (BELA) in northwestern Alaska. Two primary gradients in lichen community composition were related to habitat rockiness and a substrate-topographic gradient. Next, I sought impacts of grazing by reindeer and caribou on lichen communities. I found lightly grazed areas had taller lichens, greater total lichen cover and minor but significant changes in community structure than heavily grazed sites. Lichen species richness, however, did not differ by grazing status. To create a generalized recovery model, I used plots in burned areas and found total lichen and bryophyte cover varied with time since fire (range 4-49 yrs since fire), while vascular plant cover showed no trend. I then compared these patterns to BELA, an area of unknown disturbance history. Low lichen cover in BELA may not necessarily reflect disturbance but rather site or climatic differences. Lastly, I found that all 17 GIS variables separated lichen communities to some degree. Separation of lichen communities by variable ranged from strong (Alaska Subsections, soil and surficial geology variables) to weak (Watersheds and Reindeer Ownership). The quality of the underlying relationships, how finely the groups are divided and the average patch size of each variable also contribute to differences in how clearly lichen communities were separated. This work will serve as a baseline for future comparisons to understand implications of climate and land use change on lichen communities. My grazing results may inform managers of the implications of heavy grazing and underscore protection and monitoring of prolific and diverse sites. In addition, this work contributes a new method to age tundra communities and a list of GIS variable successful at separating lichen communities. Title: Community gradients of Arctic macrolichens in relation to succession, grazing and the environment Author: Holt, Emily A. The purpose of this dissertation was to define macrolichen community gradients in relation to succession, grazing and the environment. First, species scores indicating when macrolichen species appeared following disturbance were derived from the literature. Weighted averaging of these data with a community matrix created a successional score for each sample unit of interest. These scores are surrogates for community age for subsequent analyses. I then described lichen community structure and its relation to the environment in the Bering Land Bridge National Preserve (BELA) in northwestern Alaska. Two primary gradients in lichen community composition were related to habitat rockiness and a substrate-topographic gradient. Next, I sought impacts of grazing by reindeer and caribou on lichen communities. I found lightly grazed areas had taller lichens, greater total lichen cover and minor but significant changes in community structure than heavily grazed sites. Lichen species richness, however, did not differ by grazing status. To create a generalized recovery model, I used plots in burned areas and found total lichen and bryophyte cover varied with time since fire (range 4-49 yrs since fire), while vascular plant cover showed no trend. I then compared these patterns to BELA, an area of unknown disturbance history. Low lichen cover in BELA may not necessarily reflect disturbance but rather site or climatic differences. Lastly, I found that all 17 GIS variables separated lichen communities to some degree. Separation of lichen communities by variable ranged from strong (Alaska Subsections, soil and surficial geology variables) to weak (Watersheds and Reindeer Ownership). The quality of the underlying relationships, how finely the groups are divided and the average patch size of each variable also contribute to differences in how clearly lichen communities were separated. This work will serve as a baseline for future comparisons to understand implications of climate and land use change on lichen communities. My grazing results may inform managers of the implications of heavy grazing and underscore protection and monitoring of prolific and diverse sites. In addition, this work contributes a new method to age tundra communities and a list of GIS variable successful at separating lichen communities. Close

• 88. [Article] Lichen communities and species indicate climate thresholds in southeast and south-central Alaska, USA

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by The American Bryological and Lichenological Society, Inc., and can be found at: ...

  Citation × Citation Citation Abstract Copy Title: Lichen communities and species indicate climate thresholds in southeast and south-central Alaska, USA Author: McCune, Bruce, Root, Heather T., Jovan, Sarah This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by The American Bryological and Lichenological Society, Inc., and can be found at: http://www.bioone.org/loi/bryo Title: Lichen communities and species indicate climate thresholds in southeast and south-central Alaska, USA Author: McCune, Bruce, Root, Heather T., Jovan, Sarah This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by The American Bryological and Lichenological Society, Inc., and can be found at: http://www.bioone.org/loi/bryo Close

• 89. [Article] Growth rates and species composition of juvenile rockfish (Sebastes spp.) in Oregon’s nearshore and estuarine habitats

  Identification of critical habitat for all life stages of commercially exploited fish populations is critical for effective management. Despite a clear need for basic biological information on juvenile ...

  Citation × Citation Citation Abstract Copy Title: Growth rates and species composition of juvenile rockfish (Sebastes spp.) in Oregon’s nearshore and estuarine habitats Author: Gallagher, M. Brett Identification of critical habitat for all life stages of commercially exploited fish populations is critical for effective management. Despite a clear need for basic biological information on juvenile rockfish life history, there have been very few efforts to describe distribution and habitat of this life stage, particularly along the Oregon coast. This study investigated the relationships between habitat-type, species composition and growth of juvenile rockfishes following settlement into nearshore reefs and estuaries. By using a four-level classification system to prioritize and identify Essential Fish Habitat, results of this study refine scientific knowledge of EFH for Oregon’s nearshore rockfish species. Four species of rockfish were collected during the summers of 2004 and 2005. blue rockfish (S. mystinus), black rockfish (S. melanops), yellowtail rockfish (S. flavidus) and widow rockfish (S. entomelas). Nearshore hand net samples were dominated by blue rockfish. Estuary samples were almost exclusively black rockfish, indicating that this species is common in Yaquina Bay. No black rockfish were collected from our nearshore sampling sites in either 2004 or 2005, although this habitat is listed as common for juveniles of this species. Identification of critical habitat for all life stages of commercially exploited fish populations is critical for effective management. Despite a clear need for basic biological information on juvenile rockfish life history, there have been very few efforts to describe distribution and habitat of this life stage, particularly along the Oregon coast. This study investigated the relationships between habitat-type, species composition and growth of juvenile rockfishes following settlement into nearshore reefs and estuaries. By using a four-level classification system to prioritize and identify Essential Fish Habitat, results of this study refine scientific knowledge of EFH for Oregon’s nearshore rockfish species. Four species of rockfish were collected during the summers of 2004 and 2005. blue rockfish (S. mystinus), black rockfish (S. melanops), yellowtail rockfish (S. flavidus) and widow rockfish (S. entomelas). Nearshore hand net samples were dominated by blue rockfish. Estuary samples were almost exclusively black rockfish, indicating that this species is common in Yaquina Bay. No black rockfish were collected from our nearshore sampling sites in either 2004 or 2005, although this habitat is listed as common for juveniles of this species. Blue rockfish settlement was detected from April thru July in 2004, and from May thru June in 2005. Peak settlement timing was in June of both years. Settlement for black rockfish ranged from March thru July both years, with peak settlement timing occurring in mid-May. Yellowtail and widow rockfish juveniles were rarely encountered, with settlement occurring in April and July respectively. Abundance, as estimated from catch per unit effort (CPUE) calculations, varied among years and habitats. Black rockfish were more abundant in 2004 than in 2005. Some of the highest densities were found around pilings, docks and other anthropogenic structures: CPUE decreased within rock, eelgrass, and sand habitats respectively. Growth was not significantly different among habitats for either black or blue rockfish. Growth rate differences were not significant among years for either black or blue rockfish. However, growth differences were significant between species (black 0.50 mm d-1 and blue .54 mm d-1 (two sample-t test, T stat = -3.19, df = 133 P-value <.002). Additionally, this thesis presents a tank validation experiment that investigated the validity of traps as a quantitative measure of habitat quality. This trap validation study showed that as habitat complexity increases, trap efficiency decreases. Trap attractiveness is an important source of bias when used for juvenile rockfish abundance estimation. This study demonstrates abundance estimates may be inflated in areas of low habitat complexity in the natural environment, or under-estimate the relative abundance of rockfishes within complex habitats. This study identifies estuaries as Essential Fish Habitat for black rockfish juveniles along the central Oregon coast, and nearshore reef as EFH for blue rockfish juveniles. Results of this study also provide specific information on spatial and temporal patterns of recruitment, habitat selection and growth, previously unknown for Oregon's nearshore Sebastes species. Title: Growth rates and species composition of juvenile rockfish (Sebastes spp.) in Oregon’s nearshore and estuarine habitats Author: Gallagher, M. Brett Identification of critical habitat for all life stages of commercially exploited fish populations is critical for effective management. Despite a clear need for basic biological information on juvenile rockfish life history, there have been very few efforts to describe distribution and habitat of this life stage, particularly along the Oregon coast. This study investigated the relationships between habitat-type, species composition and growth of juvenile rockfishes following settlement into nearshore reefs and estuaries. By using a four-level classification system to prioritize and identify Essential Fish Habitat, results of this study refine scientific knowledge of EFH for Oregon’s nearshore rockfish species. Four species of rockfish were collected during the summers of 2004 and 2005. blue rockfish (S. mystinus), black rockfish (S. melanops), yellowtail rockfish (S. flavidus) and widow rockfish (S. entomelas). Nearshore hand net samples were dominated by blue rockfish. Estuary samples were almost exclusively black rockfish, indicating that this species is common in Yaquina Bay. No black rockfish were collected from our nearshore sampling sites in either 2004 or 2005, although this habitat is listed as common for juveniles of this species. Identification of critical habitat for all life stages of commercially exploited fish populations is critical for effective management. Despite a clear need for basic biological information on juvenile rockfish life history, there have been very few efforts to describe distribution and habitat of this life stage, particularly along the Oregon coast. This study investigated the relationships between habitat-type, species composition and growth of juvenile rockfishes following settlement into nearshore reefs and estuaries. By using a four-level classification system to prioritize and identify Essential Fish Habitat, results of this study refine scientific knowledge of EFH for Oregon’s nearshore rockfish species. Four species of rockfish were collected during the summers of 2004 and 2005. blue rockfish (S. mystinus), black rockfish (S. melanops), yellowtail rockfish (S. flavidus) and widow rockfish (S. entomelas). Nearshore hand net samples were dominated by blue rockfish. Estuary samples were almost exclusively black rockfish, indicating that this species is common in Yaquina Bay. No black rockfish were collected from our nearshore sampling sites in either 2004 or 2005, although this habitat is listed as common for juveniles of this species. Blue rockfish settlement was detected from April thru July in 2004, and from May thru June in 2005. Peak settlement timing was in June of both years. Settlement for black rockfish ranged from March thru July both years, with peak settlement timing occurring in mid-May. Yellowtail and widow rockfish juveniles were rarely encountered, with settlement occurring in April and July respectively. Abundance, as estimated from catch per unit effort (CPUE) calculations, varied among years and habitats. Black rockfish were more abundant in 2004 than in 2005. Some of the highest densities were found around pilings, docks and other anthropogenic structures: CPUE decreased within rock, eelgrass, and sand habitats respectively. Growth was not significantly different among habitats for either black or blue rockfish. Growth rate differences were not significant among years for either black or blue rockfish. However, growth differences were significant between species (black 0.50 mm d-1 and blue .54 mm d-1 (two sample-t test, T stat = -3.19, df = 133 P-value <.002). Additionally, this thesis presents a tank validation experiment that investigated the validity of traps as a quantitative measure of habitat quality. This trap validation study showed that as habitat complexity increases, trap efficiency decreases. Trap attractiveness is an important source of bias when used for juvenile rockfish abundance estimation. This study demonstrates abundance estimates may be inflated in areas of low habitat complexity in the natural environment, or under-estimate the relative abundance of rockfishes within complex habitats. This study identifies estuaries as Essential Fish Habitat for black rockfish juveniles along the central Oregon coast, and nearshore reef as EFH for blue rockfish juveniles. Results of this study also provide specific information on spatial and temporal patterns of recruitment, habitat selection and growth, previously unknown for Oregon's nearshore Sebastes species. Close

• 90. [Article] Molecular characterization of crustacean parasite Nadelspora canceri

  Investigations into the phylogeny, genome size, and karyotype of microsporidian Nadeispora canceri were initiated to further characterize the organism. Isolates of N. canceri spores were obtained from ...

  Citation × Citation Citation Abstract Copy Title: Molecular characterization of crustacean parasite Nadelspora canceri Author: Amogan, Harold Investigations into the phylogeny, genome size, and karyotype of microsporidian Nadeispora canceri were initiated to further characterize the organism. Isolates of N. canceri spores were obtained from both Dungeness (Cancer magisrer) and red rock crabs (Cancer productus). Analysis of the ssu rDNA sequence from spore isolates of the two crab species showed 100% sequence identity among 1,081 nucleotide positions, indicating the same species of microsporidian is infecting both species of crabs. Phylogenetic studies based on the ssu rDNA sequences also showed N. canceri to be most closely related to another crustacean parasite, A meson michaelis. Sequence comparison between the two microsporidian species showed 93% sequence identity (1,001/1081 nucleotide positions). Pulsed field gel electrophoresis was used to estimate the genome size and karyotype of N. canceri isolates obtained from Dungeness and red rock crabs. Resolution of DNA bands on the pulsed field gels revealed both isolates to have a karyotype often chromosome-sized DNA bands. Estimation of the genome size revealed spore isolates from C. magister to have a total genome size of 7.44 Mb and spore isolates from C. productus to have a total genome size of 7.32 Mb. Variations detected in chromosome size culminated in a difference in the genome size between the two isolates. However, the variations in chromosome size were found not to be significant based on the Student's t-test. Title: Molecular characterization of crustacean parasite Nadelspora canceri Author: Amogan, Harold Investigations into the phylogeny, genome size, and karyotype of microsporidian Nadeispora canceri were initiated to further characterize the organism. Isolates of N. canceri spores were obtained from both Dungeness (Cancer magisrer) and red rock crabs (Cancer productus). Analysis of the ssu rDNA sequence from spore isolates of the two crab species showed 100% sequence identity among 1,081 nucleotide positions, indicating the same species of microsporidian is infecting both species of crabs. Phylogenetic studies based on the ssu rDNA sequences also showed N. canceri to be most closely related to another crustacean parasite, A meson michaelis. Sequence comparison between the two microsporidian species showed 93% sequence identity (1,001/1081 nucleotide positions). Pulsed field gel electrophoresis was used to estimate the genome size and karyotype of N. canceri isolates obtained from Dungeness and red rock crabs. Resolution of DNA bands on the pulsed field gels revealed both isolates to have a karyotype often chromosome-sized DNA bands. Estimation of the genome size revealed spore isolates from C. magister to have a total genome size of 7.44 Mb and spore isolates from C. productus to have a total genome size of 7.32 Mb. Variations detected in chromosome size culminated in a difference in the genome size between the two isolates. However, the variations in chromosome size were found not to be significant based on the Student's t-test. Close

• 91. [Article] Population Genetics of American Pika (Ochotona princeps) : Investigating Gene Flow and Genetic Diversity Across Multiple, Complex Landscapes

  American pikas (Ochotona princeps) are considered an indicator species of climate change. Adaptations for cold climates and active winters make pikas particularly sensitive to increasing temperatures. ...

  Citation × Citation Citation Abstract Copy Title: Population Genetics of American Pika (Ochotona princeps) : Investigating Gene Flow and Genetic Diversity Across Multiple, Complex Landscapes Author: Castillo, Jessica A. American pikas (Ochotona princeps) are considered an indicator species of climate change. Adaptations for cold climates and active winters make pikas particularly sensitive to increasing temperatures. This, combined with evidence that multiple historically occupied populations have been extirpated within the past century, contributed to American pikas becoming a focal species for climate change research. This dissertation is primarily the product of a collaboration among the National Parks Service and multiple academic institutions whose principal goal was to assess the vulnerability of the American pika within eight national parks representing a variety of habitat types and environmental conditions. While much of the previous climate change-related research on American pikas has focused on how climate affects occupancy, this work sought to establish how landscape characteristics and climate may interact and influence dispersal, population connectivity, and ultimately population vulnerability or resilience. I addressed these questions using population and landscape genetics approaches within nine national parks, two national wildlife refuges, and a national forest. American pikas represent one of the best described mammalian metapopulation systems. They are restricted to rocky habitats, such as talus and lava, which are frequently patchily distributed on the landscape, both at the local and regional scales. Functional connectivity, the combination of habitat configuration and an organism’s ability to move through the landscape, is essential for maintaining robust genetic populations. This is particularly true within metapopulations which, by definition, rely on dispersal of individuals among habitat patches for overall long-term stability. In Chapters 1 and 2, I used a landscape genetics approach to identify features that either promote or inhibit dispersal of American pikas. There has been significant debate over the past few years about the best statistical approaches within landscape genetics and the appropriateness of certain methods in particular. In Chapter 1, I used Crater Lake National Park as a test case to evaluate the effectiveness of Mantel and partial Mantel tests in a causal modeling framework to correctly identify underlying landscape variables (e.g., topography, aspect, water barriers) and their effect on gene flow. I demonstrated, through simulations, that this approach was able to correctly identify the landscape variables, but not precisely the magnitude of their effect on gene flow. I concluded that while results need to be interpreted with caution, this method was effective for identifying which variables are important in shaping functional connectivity. In Chapter 2, I applied the causal modeling approach from Chapter 1 to seven additional study sites. I identified a general trend that south-west facing aspects pose greater resistance to dispersal than north and east-facing aspects, suggesting that exposure to high temperatures may limit dispersal in American pikas. I also found that amount and configuration of habitat (i.e., rocky substrate) influenced the degree to which other landscape variables impact dispersal. I then applied the models of landscape resistance to investigate habitat patch connectivity within each site using a graph theoretic approach. This allowed me to assess overall patch connectivity, as well as identify specific patches and areas within study sites that are particularly important for maintaining functional connectivity, or in contrast, at risk of becoming isolated. Functional connectivity is an important component when assessing population vulnerability because it describes the ability of genetic material to flow through the landscape. A loss of gene flow can lead to isolation of population segments, reduction of effective population size, loss of genetic diversity and subsequent erosion of evolutionary potential, and ultimately metapopulation collapse. However, other factors including habitat area and quality, affect effective population size and population stability. Genetic diversity is the material upon which evolution acts. In the face of rapid environmental change, species must either shift their range in order to track their ecological niche, or adapt in situ to the new environment. The former strategy requires sufficient available habitat as well as dispersal ability, which is unlikely for American pikas. Genetic diversity, therefore, is an important indicator of long-term population viability. In Chapter 3, I quantified genetic diversity within thirteen study sites and investigated the relationship between genetic diversity and environmental variables related to climate as well as habitat configuration and quality. As expected, habitat area was important at both the local and regional scales. Temperature was also a significant predictor of genetic diversity, with hotter sites having lower genetic diversity. However, and somewhat surprisingly, precipitation was a better predictor of genetic diversity than temperature, with sites receiving moderate levels of precipitation having higher genetic diversity. I also compared population differentiation among study sites and identified sites that are particularly distinct. In the process of the above analyses, I also identified a previously undescribed contact zone between the northern and southern Rocky Mountain genetic lineages, recognized as separate subspecies, within Rocky Mountain National Park. Climate change is predicted to affect habitat quality and landscape permeability, both of which have detectable genetic consequences. In Chapter 4, I quantified genetic diversity and structure within two study sites, Yosemite and Lassen Volcanic National Parks, from two sampling periods separated by approximately a century in time. I extracted DNA from historic study skins housed in the University of California Berkeley Museum of Vertebrate Zoology (MVZ) and compared multilocus microsatellite genotypes to those generated from modern fecal and tissue samples. Additionally, the historic survey data, including specimens, field journals, and other artifacts, were used in a series of systematic resurveys and subsequent species distribution modelling by other researchers. The nature of national parks as protected areas affords the opportunity to isolate the effects of climate change to a greater degree than other areas that have also experienced significant land use changes. I found no evidence for a change in genetic diversity within these two sites, consistent with observations from other studies that occupancy has remained relatively stable. I did find some evidence suggesting increasing population differentiation, potentially as a result of eroding landscape permeability. These results provide an important baseline for comparison with other sites, as well as reference points for future genetic monitoring of these populations. In Chapter 5, I provide general synthesis and conclusions, as well as considerations for future research. Title: Population Genetics of American Pika (Ochotona princeps) : Investigating Gene Flow and Genetic Diversity Across Multiple, Complex Landscapes Author: Castillo, Jessica A. American pikas (Ochotona princeps) are considered an indicator species of climate change. Adaptations for cold climates and active winters make pikas particularly sensitive to increasing temperatures. This, combined with evidence that multiple historically occupied populations have been extirpated within the past century, contributed to American pikas becoming a focal species for climate change research. This dissertation is primarily the product of a collaboration among the National Parks Service and multiple academic institutions whose principal goal was to assess the vulnerability of the American pika within eight national parks representing a variety of habitat types and environmental conditions. While much of the previous climate change-related research on American pikas has focused on how climate affects occupancy, this work sought to establish how landscape characteristics and climate may interact and influence dispersal, population connectivity, and ultimately population vulnerability or resilience. I addressed these questions using population and landscape genetics approaches within nine national parks, two national wildlife refuges, and a national forest. American pikas represent one of the best described mammalian metapopulation systems. They are restricted to rocky habitats, such as talus and lava, which are frequently patchily distributed on the landscape, both at the local and regional scales. Functional connectivity, the combination of habitat configuration and an organism’s ability to move through the landscape, is essential for maintaining robust genetic populations. This is particularly true within metapopulations which, by definition, rely on dispersal of individuals among habitat patches for overall long-term stability. In Chapters 1 and 2, I used a landscape genetics approach to identify features that either promote or inhibit dispersal of American pikas. There has been significant debate over the past few years about the best statistical approaches within landscape genetics and the appropriateness of certain methods in particular. In Chapter 1, I used Crater Lake National Park as a test case to evaluate the effectiveness of Mantel and partial Mantel tests in a causal modeling framework to correctly identify underlying landscape variables (e.g., topography, aspect, water barriers) and their effect on gene flow. I demonstrated, through simulations, that this approach was able to correctly identify the landscape variables, but not precisely the magnitude of their effect on gene flow. I concluded that while results need to be interpreted with caution, this method was effective for identifying which variables are important in shaping functional connectivity. In Chapter 2, I applied the causal modeling approach from Chapter 1 to seven additional study sites. I identified a general trend that south-west facing aspects pose greater resistance to dispersal than north and east-facing aspects, suggesting that exposure to high temperatures may limit dispersal in American pikas. I also found that amount and configuration of habitat (i.e., rocky substrate) influenced the degree to which other landscape variables impact dispersal. I then applied the models of landscape resistance to investigate habitat patch connectivity within each site using a graph theoretic approach. This allowed me to assess overall patch connectivity, as well as identify specific patches and areas within study sites that are particularly important for maintaining functional connectivity, or in contrast, at risk of becoming isolated. Functional connectivity is an important component when assessing population vulnerability because it describes the ability of genetic material to flow through the landscape. A loss of gene flow can lead to isolation of population segments, reduction of effective population size, loss of genetic diversity and subsequent erosion of evolutionary potential, and ultimately metapopulation collapse. However, other factors including habitat area and quality, affect effective population size and population stability. Genetic diversity is the material upon which evolution acts. In the face of rapid environmental change, species must either shift their range in order to track their ecological niche, or adapt in situ to the new environment. The former strategy requires sufficient available habitat as well as dispersal ability, which is unlikely for American pikas. Genetic diversity, therefore, is an important indicator of long-term population viability. In Chapter 3, I quantified genetic diversity within thirteen study sites and investigated the relationship between genetic diversity and environmental variables related to climate as well as habitat configuration and quality. As expected, habitat area was important at both the local and regional scales. Temperature was also a significant predictor of genetic diversity, with hotter sites having lower genetic diversity. However, and somewhat surprisingly, precipitation was a better predictor of genetic diversity than temperature, with sites receiving moderate levels of precipitation having higher genetic diversity. I also compared population differentiation among study sites and identified sites that are particularly distinct. In the process of the above analyses, I also identified a previously undescribed contact zone between the northern and southern Rocky Mountain genetic lineages, recognized as separate subspecies, within Rocky Mountain National Park. Climate change is predicted to affect habitat quality and landscape permeability, both of which have detectable genetic consequences. In Chapter 4, I quantified genetic diversity and structure within two study sites, Yosemite and Lassen Volcanic National Parks, from two sampling periods separated by approximately a century in time. I extracted DNA from historic study skins housed in the University of California Berkeley Museum of Vertebrate Zoology (MVZ) and compared multilocus microsatellite genotypes to those generated from modern fecal and tissue samples. Additionally, the historic survey data, including specimens, field journals, and other artifacts, were used in a series of systematic resurveys and subsequent species distribution modelling by other researchers. The nature of national parks as protected areas affords the opportunity to isolate the effects of climate change to a greater degree than other areas that have also experienced significant land use changes. I found no evidence for a change in genetic diversity within these two sites, consistent with observations from other studies that occupancy has remained relatively stable. I did find some evidence suggesting increasing population differentiation, potentially as a result of eroding landscape permeability. These results provide an important baseline for comparison with other sites, as well as reference points for future genetic monitoring of these populations. In Chapter 5, I provide general synthesis and conclusions, as well as considerations for future research. Close

• 92. [Article] Population genetics, systematics, and habitat associations of chanterelles in the Pacific Northwest

  Balancing resource extraction with protection of Pacific Northwest forest ecosystems requires understanding the population biology of ectomycorrhizal fungi. Design of landscape-scale management and research ...

  Citation × Citation Citation Abstract Copy Title: Population genetics, systematics, and habitat associations of chanterelles in the Pacific Northwest Author: Dunham, Susie M. Balancing resource extraction with protection of Pacific Northwest forest ecosystems requires understanding the population biology of ectomycorrhizal fungi. Design of landscape-scale management and research strategies requires understanding genet size, habitat requirements, and dispersal capabilities. The purpose of this dissertation was to gain knowledge about the distribution of genetic variation, systematics, and habitat associations of chanterelles (Cantharellus sp.). Population genetic markers were required to complete this research. I developed and characterized five co-dominant microsatellite markers and used them to study Pacific golden chanterelle (C. form osus) genet size and its relation to forest disturbance. Genetic data indicated that C. formosus collections included a cryptic chanterelle species. Small (<4 m diameter) genets were characterized for both genetic types and there was no evidence that genet size differed across disturbance treatments. Three genetic and one morphological data set were colleted to determine if the genetic variability observed during the genet study was indicative of species boundaries. These data were used in combination to characterize a new species of yellow chanterelle, C. cascadensis nom. prov. Microsatellite data provide evidence that C. subalbidus, C. cascadensis nom. prov., and C. form osus do not interbreed when they co-occur spatially. Morphological data indicate that pileus color and stipe shape can be used to separate fresh collections of C. formosus and C. cascadensis nom. prov. I also determined the habitat associations of three chanterelle species with respect to stand age. At the watershed scale stand age is a good predictor of the distribution of C. subalbidus and C.formosus, but is only marginally important for C. cascadensis nom. prov. To characterize chanterelle dispersal capabilities I used spatial autocorrelation analysis to examine the withinpopulation genetic structure of C. formosus. Positive spatial autocorrelation was detected estimating a 200 m radius for genetically homogeneous patches for C. form osus indicating that limited spore dispersal possibly coupled with inbreeding works to maintain fine scale genetic structure in this species. Title: Population genetics, systematics, and habitat associations of chanterelles in the Pacific Northwest Author: Dunham, Susie M. Balancing resource extraction with protection of Pacific Northwest forest ecosystems requires understanding the population biology of ectomycorrhizal fungi. Design of landscape-scale management and research strategies requires understanding genet size, habitat requirements, and dispersal capabilities. The purpose of this dissertation was to gain knowledge about the distribution of genetic variation, systematics, and habitat associations of chanterelles (Cantharellus sp.). Population genetic markers were required to complete this research. I developed and characterized five co-dominant microsatellite markers and used them to study Pacific golden chanterelle (C. form osus) genet size and its relation to forest disturbance. Genetic data indicated that C. formosus collections included a cryptic chanterelle species. Small (<4 m diameter) genets were characterized for both genetic types and there was no evidence that genet size differed across disturbance treatments. Three genetic and one morphological data set were colleted to determine if the genetic variability observed during the genet study was indicative of species boundaries. These data were used in combination to characterize a new species of yellow chanterelle, C. cascadensis nom. prov. Microsatellite data provide evidence that C. subalbidus, C. cascadensis nom. prov., and C. form osus do not interbreed when they co-occur spatially. Morphological data indicate that pileus color and stipe shape can be used to separate fresh collections of C. formosus and C. cascadensis nom. prov. I also determined the habitat associations of three chanterelle species with respect to stand age. At the watershed scale stand age is a good predictor of the distribution of C. subalbidus and C.formosus, but is only marginally important for C. cascadensis nom. prov. To characterize chanterelle dispersal capabilities I used spatial autocorrelation analysis to examine the withinpopulation genetic structure of C. formosus. Positive spatial autocorrelation was detected estimating a 200 m radius for genetically homogeneous patches for C. form osus indicating that limited spore dispersal possibly coupled with inbreeding works to maintain fine scale genetic structure in this species. Close

• 93. [Article] Murray's law, the ‘Yarrum’ optimum, and the hydraulic architecture of compound leaves

  The definitive version of this article is available at www.newphytologist.com.

  Citation × Citation Citation Abstract Copy Title: Murray's law, the ‘Yarrum’ optimum, and the hydraulic architecture of compound leaves Author: Meinzer, F. C., Lachenbruch, B., McCulloh, K. A., Atala, C., Sperry, J. S. The definitive version of this article is available at www.newphytologist.com. Title: Murray's law, the ‘Yarrum’ optimum, and the hydraulic architecture of compound leaves Author: Meinzer, F. C., Lachenbruch, B., McCulloh, K. A., Atala, C., Sperry, J. S. The definitive version of this article is available at www.newphytologist.com. Close

• 94. [Article] Determination of trace concentrations of cobalt via lucigenin chemiluminescence

  The application of lucigenin chemiluminescence for the determination of trace concentrations of Co(II) is described. This method is based on the enhancing effect that Co(II) has on the reaction of lucigenin ...

  Citation × Citation Citation Abstract Copy Title: Determination of trace concentrations of cobalt via lucigenin chemiluminescence Author: Montano, Laurence Alan The application of lucigenin chemiluminescence for the determination of trace concentrations of Co(II) is described. This method is based on the enhancing effect that Co(II) has on the reaction of lucigenin and hydrogen peroxide in a basic solution. The chemiluminescence signal from a Co(II) enhanced lucigenin reaction, which is in excess of the signal in the absence of added metal activators, is proportional to the Co(II) concentration. The instrumentation used in the study was a previously constructed chemiluminescence photometer. The photometer is the discrete sampling system type and the luminescent signal was monitored with a photomultiplier tube. Several improvements were made to the existing instrumentation in order to minimize contamination, improve the reproducibility of the chemiluminescent signals, and decrease the analysis time. The mixing order of the reagents, their concentration and volumes, and other reaction conditions were optimized. The Co calibration curve is linear from the detection limit, 15 pptr, up to 100 ppm. A comprehensive interference study of 88 species (metals, nonmetals, common anions, and complexing agents) indicated that many species enhance or inhibit the lucigenin reaction. In many samples, most of these potential interferents are not present at a large enough concentration to interfere with the determination of ppb and sub-ppb concentrations of Co(II). A solvent extraction separation procedure was developed to isolate Co from its matrix and the most troublesome interferences (Mg and Fe), and it was used in the analysis of NBS orchard leaves. The analysis of five orchard leaves samples indicated that the Co concentration was 0.12 ppm and the relative precision was 18%. Direct analysis of a spiked tap water sample showed that dilution can be used to eliminate interferences as long as the Co concentration in the sample is at least 5 ppb. The chemiluminescent reaction of lucigenin in a strongly basic solution in the absence of hydrogen peroxide was studied and various absorption, fluorescence, and chemiluminescent spectra were obtained. The reactivity of several Co(III) complexes was investigated as well as the effect of bubbling the reaction solutions with O₂, N₂, H₂, and Ar. Title: Determination of trace concentrations of cobalt via lucigenin chemiluminescence Author: Montano, Laurence Alan The application of lucigenin chemiluminescence for the determination of trace concentrations of Co(II) is described. This method is based on the enhancing effect that Co(II) has on the reaction of lucigenin and hydrogen peroxide in a basic solution. The chemiluminescence signal from a Co(II) enhanced lucigenin reaction, which is in excess of the signal in the absence of added metal activators, is proportional to the Co(II) concentration. The instrumentation used in the study was a previously constructed chemiluminescence photometer. The photometer is the discrete sampling system type and the luminescent signal was monitored with a photomultiplier tube. Several improvements were made to the existing instrumentation in order to minimize contamination, improve the reproducibility of the chemiluminescent signals, and decrease the analysis time. The mixing order of the reagents, their concentration and volumes, and other reaction conditions were optimized. The Co calibration curve is linear from the detection limit, 15 pptr, up to 100 ppm. A comprehensive interference study of 88 species (metals, nonmetals, common anions, and complexing agents) indicated that many species enhance or inhibit the lucigenin reaction. In many samples, most of these potential interferents are not present at a large enough concentration to interfere with the determination of ppb and sub-ppb concentrations of Co(II). A solvent extraction separation procedure was developed to isolate Co from its matrix and the most troublesome interferences (Mg and Fe), and it was used in the analysis of NBS orchard leaves. The analysis of five orchard leaves samples indicated that the Co concentration was 0.12 ppm and the relative precision was 18%. Direct analysis of a spiked tap water sample showed that dilution can be used to eliminate interferences as long as the Co concentration in the sample is at least 5 ppb. The chemiluminescent reaction of lucigenin in a strongly basic solution in the absence of hydrogen peroxide was studied and various absorption, fluorescence, and chemiluminescent spectra were obtained. The reactivity of several Co(III) complexes was investigated as well as the effect of bubbling the reaction solutions with O₂, N₂, H₂, and Ar. Close

• 95. [Article] Searching for viable exploitation within small scale fisheries; the case of Solomon Islands

  Abstract Only

  Citation × Citation Citation Abstract Copy Title: Searching for viable exploitation within small scale fisheries; the case of Solomon Islands Author: Doyen, Luc, Hardy, Pierre-Yves, Bene, Christophe, Schwarz, Anne-Maree Abstract Only Title: Searching for viable exploitation within small scale fisheries; the case of Solomon Islands Author: Doyen, Luc, Hardy, Pierre-Yves, Bene, Christophe, Schwarz, Anne-Maree Abstract Only Close

• 96. [Article] Searching for viable exploitation within small scale fisheries; the case of Solomon Islands

  Abstract only

  Citation × Citation Citation Abstract Copy Title: Searching for viable exploitation within small scale fisheries; the case of Solomon Islands Author: Doyen, Luc, Hardy, Pierre-Yves, Bene, Christophe, Schwarz, Anne-Maree Abstract only Title: Searching for viable exploitation within small scale fisheries; the case of Solomon Islands Author: Doyen, Luc, Hardy, Pierre-Yves, Bene, Christophe, Schwarz, Anne-Maree Abstract only Close

• 97. [Article] Benthic macroinvertebrates and sediment characteristics of a coastal dune margin lake (Carter Lake, Douglas County, Oregon)

  Carter Lake, a freshwater, coastal dune-margin lake, was sampled at the beginning and end of the summer of 1986 to determine the sediment characteristics and benthic macroinvertebrate abundance, biomass, ...

  Citation × Citation Citation Abstract Copy Title: Benthic macroinvertebrates and sediment characteristics of a coastal dune margin lake (Carter Lake, Douglas County, Oregon) Author: Wones, Andrew G. Carter Lake, a freshwater, coastal dune-margin lake, was sampled at the beginning and end of the summer of 1986 to determine the sediment characteristics and benthic macroinvertebrate abundance, biomass, variety, and diversity. The distributions of major benthic habitats were estimated by snorkeling in June and July, 1986. Water temperature and dissolved oxygen were measured throughout the summer of 1986. In July 1987, water temperature, dissolved oxygen, conductivity, alkalinity and pH were determined. Thermal stratification was not observed during this study and the water column warmed gradually between April and July. Dissolved oxygen remained close to 100% saturation throughout the study. The water level of Carter Lake dropped about 2.5 m between May and October, reducing its surface area by about 40%. The benthic habitats of Carter Lake were stratified into four major zones: a sandy temporarily submerged littoral zone; a sandy but permanently submerged littoral zone; a mid-depth zone where a macrophyte, Nitella. grew; and a deep zone with soft mud substrate. The average density of benthic macroinvertebrates was highest in the shallow permanently submerged zone ( >16000 / m² in May and October ) and lowest in the deep mud zone ( 2900 / m² in May and 4700 / m² in October ). In May, benthic macroinvertebrate biomass was highest in the shallow zones ( 1.3 - 2.9 g / m² dry weight ); in October biomass was highest in the mid-depth zone ( 4.4 g/m² dry weight, excluding crayfish and mussels ). Fifty-three invertebrate taxa were identified from Carter Lake, including three euryhaline crustacean species ( Corophium spinicorne. Gnorimosphaeroma oregonensis lutea. and Acanthomysis awatchensis ) . Corophium spinicorne dominated the macroinvertebrate communities of the shallow areas and sphaeriid clams dominated the deep water community. The mid-depth zone had the most diverse community. Two species that were abundant in the temporarily submerged area, Corophium spinicorne and Juga piicifera. were found in greater numbers deeper in the lake after the water level dropped, indicating that these species migrate in response to changing water level. Title: Benthic macroinvertebrates and sediment characteristics of a coastal dune margin lake (Carter Lake, Douglas County, Oregon) Author: Wones, Andrew G. Carter Lake, a freshwater, coastal dune-margin lake, was sampled at the beginning and end of the summer of 1986 to determine the sediment characteristics and benthic macroinvertebrate abundance, biomass, variety, and diversity. The distributions of major benthic habitats were estimated by snorkeling in June and July, 1986. Water temperature and dissolved oxygen were measured throughout the summer of 1986. In July 1987, water temperature, dissolved oxygen, conductivity, alkalinity and pH were determined. Thermal stratification was not observed during this study and the water column warmed gradually between April and July. Dissolved oxygen remained close to 100% saturation throughout the study. The water level of Carter Lake dropped about 2.5 m between May and October, reducing its surface area by about 40%. The benthic habitats of Carter Lake were stratified into four major zones: a sandy temporarily submerged littoral zone; a sandy but permanently submerged littoral zone; a mid-depth zone where a macrophyte, Nitella. grew; and a deep zone with soft mud substrate. The average density of benthic macroinvertebrates was highest in the shallow permanently submerged zone ( >16000 / m² in May and October ) and lowest in the deep mud zone ( 2900 / m² in May and 4700 / m² in October ). In May, benthic macroinvertebrate biomass was highest in the shallow zones ( 1.3 - 2.9 g / m² dry weight ); in October biomass was highest in the mid-depth zone ( 4.4 g/m² dry weight, excluding crayfish and mussels ). Fifty-three invertebrate taxa were identified from Carter Lake, including three euryhaline crustacean species ( Corophium spinicorne. Gnorimosphaeroma oregonensis lutea. and Acanthomysis awatchensis ) . Corophium spinicorne dominated the macroinvertebrate communities of the shallow areas and sphaeriid clams dominated the deep water community. The mid-depth zone had the most diverse community. Two species that were abundant in the temporarily submerged area, Corophium spinicorne and Juga piicifera. were found in greater numbers deeper in the lake after the water level dropped, indicating that these species migrate in response to changing water level. Close

• 98. [Article] Canyon Grasslands of the Hells Canyon National Recreation Area : How have they changed over time and what is their future trajectory?

  The canyon grasslands of the Hells Canyon National Recreation Area (HCNRA) are a unique ecosystem within the Pacific Northwest Bunchgrass Region (PNWBR) with a long history of natural and anthropogenic ...

  Citation × Citation Citation Abstract Copy Title: Canyon Grasslands of the Hells Canyon National Recreation Area : How have they changed over time and what is their future trajectory? Author: Pack, Samantha J. The canyon grasslands of the Hells Canyon National Recreation Area (HCNRA) are a unique ecosystem within the Pacific Northwest Bunchgrass Region (PNWBR) with a long history of natural and anthropogenic disturbances including fire, invasive species introduction, historical livestock grazing, and cultivation. Even with this history, these canyon grasslands contain some of the last remnants of the Pacific Northwest Bunchgrass Region. For thousands of years, these grasslands were occupied by the Nez Perce Tribe and have been grazed since the 1700s. In addition to grazing, settlers cultivated many parts of the HCNRA and some of these homesteads can still be seen today. Both historical and current land uses are strongly influenced by the natural topography of these canyon grasslands, with the highest concentration of land use centered on benchlands while steep canyon slopes avoided cultivation and were used less by livestock. The different plant associations of these grasslands are also influenced by the unique topography of the HCNRA due to the relationships between soil moisture and depth and abrupt alterations in aspect, slope, and elevation. Very few studies have examined the plant associations of the canyon grasslands of the HCNRA, even fewer have asked how they have changed over time, and there are no studies looking into their future trajectory by assessing the seed bank. The first study in my thesis (Chapter 2) focused on how canyon grasslands have changed over time using a repeated survey of vegetation from four different plant associations within the Lower Imnaha Subbasin. From the original study conducted in 1981, a total of 19 different plots in four plant associations were chosen to be resampled in 2014. Since the original study was used to classify seral stages within the plant associations, these successional stages were used to determine if the plant communities had transitioned between the seral classes over the 33 year-time-period. In addition, given the importance of topography to these grasslands, elevation, slope, and aspect were evaluated for their relationship to successional changes. Both Nonmetric Multidimensional Scaling (NMS) and Indicator Species Analysis were used to verify the seral stage classifications for each plot in 1981 and 2014. To evaluate how each association had changed between sampling years, Multi-response Permutation Procedures (MRPP) and NMS were used. Most of these plant associations were relatively stable and had, for the most part, remained at the same seral stage or transitioned to a later seral stage. Among the plant associations, slope was the topographical variable that appeared most related to the transitions in seral stages. Steeper slopes either remained at the same seral stage or transitioned to a later one, while gentler slopes (< 20%) tended to shift from later to earlier seral stages. A relatively new introduced annual grass to the region, Ventenata dubia (not present in the 1981 sampling), was found in three of the four plant associations and was most abundant on the benchlands. The results of this resurvey suggest that topography is related to both the distribution of plant associations and which sites will shift in seral stage over time across the canyon grasslands of the Lower Imnaha Subbasin. The second study of my thesis (Chapter 3) focused on using a seed bank study as one of the many ways to examine the future trajectory of the plant communities in the canyon grasslands of the Lower Imnaha Subbasin, with a particular focus on the benchlands. The seed bank contains the regenerative pool for plant communities and represents the potential for a community to respond to disturbances. The seed bank from benchland sites in one plant association was evaluated in relation to the standing vegetation, successional stage, and historical cultivation. To my knowledge, this was the first seed bank study for the grasslands of this region. Vegetation cover and soil samples were collected from 8 sites, including two previously cultivated and two reference noncultivated sites. NMS was used to extract the strongest community gradients, which naturally separated out the seral stage classifications of the vegetation. To evaluate differences between the vegetation and the seed bank, between successional stages, and between cultivation histories, MRPP was used. Results from the seed bank study are consistent with many other studies around the world in perennial grasslands showing that the vegetation and seed bank are often dissimilar. Similarities between the vegetation and seed bank were highest in the annual grass dominated stage compared to the early seral stage. The effects of cultivation appear to still be evident in the seed bank, where cultivated sites have significantly more introduced grasses compared to noncultivated sites (p < 0.05). There was an overall greater abundance of introduced annual forb and grass species in the seed bank on these benchland sites, suggesting that they may be native seed limited and could easily shift to invasive species dominance after further disturbance, especially on previously cultivated areas. The results of both of these studies suggest that benchlands and lower sloped sites surrounding them in the canyon grasslands of the Lower Imnaha Subbasin may less resistant and resilient to disturbance. Priorities for future research and management may also need to focus on the plant communities of benchlands in these unique grasslands. Title: Canyon Grasslands of the Hells Canyon National Recreation Area : How have they changed over time and what is their future trajectory? Author: Pack, Samantha J. The canyon grasslands of the Hells Canyon National Recreation Area (HCNRA) are a unique ecosystem within the Pacific Northwest Bunchgrass Region (PNWBR) with a long history of natural and anthropogenic disturbances including fire, invasive species introduction, historical livestock grazing, and cultivation. Even with this history, these canyon grasslands contain some of the last remnants of the Pacific Northwest Bunchgrass Region. For thousands of years, these grasslands were occupied by the Nez Perce Tribe and have been grazed since the 1700s. In addition to grazing, settlers cultivated many parts of the HCNRA and some of these homesteads can still be seen today. Both historical and current land uses are strongly influenced by the natural topography of these canyon grasslands, with the highest concentration of land use centered on benchlands while steep canyon slopes avoided cultivation and were used less by livestock. The different plant associations of these grasslands are also influenced by the unique topography of the HCNRA due to the relationships between soil moisture and depth and abrupt alterations in aspect, slope, and elevation. Very few studies have examined the plant associations of the canyon grasslands of the HCNRA, even fewer have asked how they have changed over time, and there are no studies looking into their future trajectory by assessing the seed bank. The first study in my thesis (Chapter 2) focused on how canyon grasslands have changed over time using a repeated survey of vegetation from four different plant associations within the Lower Imnaha Subbasin. From the original study conducted in 1981, a total of 19 different plots in four plant associations were chosen to be resampled in 2014. Since the original study was used to classify seral stages within the plant associations, these successional stages were used to determine if the plant communities had transitioned between the seral classes over the 33 year-time-period. In addition, given the importance of topography to these grasslands, elevation, slope, and aspect were evaluated for their relationship to successional changes. Both Nonmetric Multidimensional Scaling (NMS) and Indicator Species Analysis were used to verify the seral stage classifications for each plot in 1981 and 2014. To evaluate how each association had changed between sampling years, Multi-response Permutation Procedures (MRPP) and NMS were used. Most of these plant associations were relatively stable and had, for the most part, remained at the same seral stage or transitioned to a later seral stage. Among the plant associations, slope was the topographical variable that appeared most related to the transitions in seral stages. Steeper slopes either remained at the same seral stage or transitioned to a later one, while gentler slopes (< 20%) tended to shift from later to earlier seral stages. A relatively new introduced annual grass to the region, Ventenata dubia (not present in the 1981 sampling), was found in three of the four plant associations and was most abundant on the benchlands. The results of this resurvey suggest that topography is related to both the distribution of plant associations and which sites will shift in seral stage over time across the canyon grasslands of the Lower Imnaha Subbasin. The second study of my thesis (Chapter 3) focused on using a seed bank study as one of the many ways to examine the future trajectory of the plant communities in the canyon grasslands of the Lower Imnaha Subbasin, with a particular focus on the benchlands. The seed bank contains the regenerative pool for plant communities and represents the potential for a community to respond to disturbances. The seed bank from benchland sites in one plant association was evaluated in relation to the standing vegetation, successional stage, and historical cultivation. To my knowledge, this was the first seed bank study for the grasslands of this region. Vegetation cover and soil samples were collected from 8 sites, including two previously cultivated and two reference noncultivated sites. NMS was used to extract the strongest community gradients, which naturally separated out the seral stage classifications of the vegetation. To evaluate differences between the vegetation and the seed bank, between successional stages, and between cultivation histories, MRPP was used. Results from the seed bank study are consistent with many other studies around the world in perennial grasslands showing that the vegetation and seed bank are often dissimilar. Similarities between the vegetation and seed bank were highest in the annual grass dominated stage compared to the early seral stage. The effects of cultivation appear to still be evident in the seed bank, where cultivated sites have significantly more introduced grasses compared to noncultivated sites (p < 0.05). There was an overall greater abundance of introduced annual forb and grass species in the seed bank on these benchland sites, suggesting that they may be native seed limited and could easily shift to invasive species dominance after further disturbance, especially on previously cultivated areas. The results of both of these studies suggest that benchlands and lower sloped sites surrounding them in the canyon grasslands of the Lower Imnaha Subbasin may less resistant and resilient to disturbance. Priorities for future research and management may also need to focus on the plant communities of benchlands in these unique grasslands. Close

• 99. [Article] Early competitive environments differentially influence stress axis responses in sympatric, ecologically similar songbirds

  1. Early competitive environments can shape the development of offspring across taxa. For example, competition for food can have downstream effects on offspring phenotypes and fitness; however, little ...

  Citation × Citation Citation Abstract Copy Title: Early competitive environments differentially influence stress axis responses in sympatric, ecologically similar songbirds Author: Hardt, Braelei M 1. Early competitive environments can shape the development of offspring across taxa. For example, competition for food can have downstream effects on offspring phenotypes and fitness; however, little is known about how early competition influences the development of the hypothalamic-pituitary axis and its potential tradeoff with growth. Because baseline and stressor-induced concentrations of glucocorticoids serve different purposes yet are central to survival, both should be evaluated both when assessing these potential tradeoffs. 2. We used a reciprocal partial cross-fostering study design in a free-living population of two species of sympatric, closely related bird species to test the hypothesis that increased competition during post-natal development leads to tradeoffs in the production of corticosterone (CORT), the primary glucocorticoid in birds, and growth. In addition, we tested the extent to which these responses differed between closely related species experiencing the same experimental conditions. 3. We found that nestlings of both species had elevated concentrations of both baseline and stressor-induced CORT in enlarged broods relative to control and reduced broods. In addition, we detected higher stressor-induced CORT in Violet-green Swallows (Tachycineta thalassina) when compared to Tree Swallows (T. bicolor) across treatments. 4. Violet-green Swallows grew slower than Tree Swallows in all treatments, and growth rate tended to decrease as brood size increased in both species. Further, we did not detect a treatment effect on the offspring survivorship to fledge or length of nesting period. Thus, elevated levels of CORT appear to be adaptive via changes that maintain nest survival rates under challenging conditions, such as when brood competition is high. 5. Our study showed that nestlings of closely related species that experience the same environmental stressors can diverge in their CORT response, indicating that species-level variation in CORT expression may be more important than environmental drivers. Further, we found that variation in early competition can lead to changes in CORT expression in swallows, and that this expression trades off with growth when brood competition is high. CORT may play a key role for balancing energetic demands that arise in the face of nestmate competition. Title: Early competitive environments differentially influence stress axis responses in sympatric, ecologically similar songbirds Author: Hardt, Braelei M 1. Early competitive environments can shape the development of offspring across taxa. For example, competition for food can have downstream effects on offspring phenotypes and fitness; however, little is known about how early competition influences the development of the hypothalamic-pituitary axis and its potential tradeoff with growth. Because baseline and stressor-induced concentrations of glucocorticoids serve different purposes yet are central to survival, both should be evaluated both when assessing these potential tradeoffs. 2. We used a reciprocal partial cross-fostering study design in a free-living population of two species of sympatric, closely related bird species to test the hypothesis that increased competition during post-natal development leads to tradeoffs in the production of corticosterone (CORT), the primary glucocorticoid in birds, and growth. In addition, we tested the extent to which these responses differed between closely related species experiencing the same experimental conditions. 3. We found that nestlings of both species had elevated concentrations of both baseline and stressor-induced CORT in enlarged broods relative to control and reduced broods. In addition, we detected higher stressor-induced CORT in Violet-green Swallows (Tachycineta thalassina) when compared to Tree Swallows (T. bicolor) across treatments. 4. Violet-green Swallows grew slower than Tree Swallows in all treatments, and growth rate tended to decrease as brood size increased in both species. Further, we did not detect a treatment effect on the offspring survivorship to fledge or length of nesting period. Thus, elevated levels of CORT appear to be adaptive via changes that maintain nest survival rates under challenging conditions, such as when brood competition is high. 5. Our study showed that nestlings of closely related species that experience the same environmental stressors can diverge in their CORT response, indicating that species-level variation in CORT expression may be more important than environmental drivers. Further, we found that variation in early competition can lead to changes in CORT expression in swallows, and that this expression trades off with growth when brood competition is high. CORT may play a key role for balancing energetic demands that arise in the face of nestmate competition. Close

• 100. [Article] Limnology of Upper Klamath Lake, Oregon, with emphasis on benthos

  Aspects of the limnology and benthic ecology of Upper Klamath Lake, Oregon, are described emphasizing those features that identify its uniqueness. The lake is large, shallow, and characterized by nuisance ...

  Citation × Citation Citation Abstract Copy Title: Limnology of Upper Klamath Lake, Oregon, with emphasis on benthos Author: Hazel, Charles R. Aspects of the limnology and benthic ecology of Upper Klamath Lake, Oregon, are described emphasizing those features that identify its uniqueness. The lake is large, shallow, and characterized by nuisance abundances of Aphanizomenon flos-aquae and midge flies. Results of this study indicate that it does not stratify and dissolved oxygen is sufficient to support game fish except in localized embayments. Although temperatures exceed 70°F and pH is between 9 and 10 during late summer, the lake supports a good trout fishery. Light penetration is limited with extinction coefficients between 1.32 and 11.56. Turbidity was demonstrated to result from both the massive blooms of Aphanizomenon and the resuspension of bottom sediments. Water mass movements of the order of 0.02 ft/sec or more was needed to resuspend bottom sediments. This resuspension occurred almost daily and sediments were mixed throughout the column of water. An estimate of the oxygen demand of bottom sediments was 1.14 mg/sq. ft/day. Zooplankton, benthos, and fishes were collected, identified, and categorized by habitat type, Daphnia schodleri, Diaptomus, and Cyclops are the most abundant zooplankters. The diatomaceous ooze that covers nearly 100 percent of the bottom of the lake is inhabited primarily by Oligochaete worms, leeches (Helobdella and Glossiphonia), midge larvae, and snails in that respective order of abundance. A large variety of benthic organisms inhabit the many habitats found at the edge of the lake. Artificial substrate experiments carried out in the lake indicated that some species are limited in their distributions by a lack of proper substrate. Apparent substrate preferences were demonstrated to be influenced by size of the organism, time of incubation of the sampler, and possibly by predation by leeches. Title: Limnology of Upper Klamath Lake, Oregon, with emphasis on benthos Author: Hazel, Charles R. Aspects of the limnology and benthic ecology of Upper Klamath Lake, Oregon, are described emphasizing those features that identify its uniqueness. The lake is large, shallow, and characterized by nuisance abundances of Aphanizomenon flos-aquae and midge flies. Results of this study indicate that it does not stratify and dissolved oxygen is sufficient to support game fish except in localized embayments. Although temperatures exceed 70°F and pH is between 9 and 10 during late summer, the lake supports a good trout fishery. Light penetration is limited with extinction coefficients between 1.32 and 11.56. Turbidity was demonstrated to result from both the massive blooms of Aphanizomenon and the resuspension of bottom sediments. Water mass movements of the order of 0.02 ft/sec or more was needed to resuspend bottom sediments. This resuspension occurred almost daily and sediments were mixed throughout the column of water. An estimate of the oxygen demand of bottom sediments was 1.14 mg/sq. ft/day. Zooplankton, benthos, and fishes were collected, identified, and categorized by habitat type, Daphnia schodleri, Diaptomus, and Cyclops are the most abundant zooplankters. The diatomaceous ooze that covers nearly 100 percent of the bottom of the lake is inhabited primarily by Oligochaete worms, leeches (Helobdella and Glossiphonia), midge larvae, and snails in that respective order of abundance. A large variety of benthic organisms inhabit the many habitats found at the edge of the lake. Artificial substrate experiments carried out in the lake indicated that some species are limited in their distributions by a lack of proper substrate. Apparent substrate preferences were demonstrated to be influenced by size of the organism, time of incubation of the sampler, and possibly by predation by leeches. Close