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• 41. [Article] Heart rate, survivorship, oxygen consumption, and metabolic end product accumulations in the intertidal limpets Collisella pelta and Collisella digitalis in relation to desiccation and hypoxia

  The heart rate, oxygen consumption, survivorship, and 1-lactate accumulation were determined in the intertidal limpets Collisella pelta and Collisella digitalis in relation to laboratory desiccation at ...

  Citation × Citation Citation Abstract Copy Title: Heart rate, survivorship, oxygen consumption, and metabolic end product accumulations in the intertidal limpets Collisella pelta and Collisella digitalis in relation to desiccation and hypoxia Author: Boese, Bruce Leon The heart rate, oxygen consumption, survivorship, and 1-lactate accumulation were determined in the intertidal limpets Collisella pelta and Collisella digitalis in relation to laboratory desiccation at 15°C or 30°C. Water loss was computed as a percentage of total initial body water (wet weight - dry weight). Although water was lost faster in C. digitalis than in C. pelta, C. digitalis tolerated more water loss and survived longer than C. pelta at both experimental temperatures. During the first few hours of desiccation at 15°C the heart rate of C. digitalis was constant while in C. pelta the heart rate declined rapidly. During desiccation at 30°C the heart rates of both species declined rapidly. No change was noted in control heart rates, determined under moist aerial conditions, in either species during a 40 hour exposure period. Oxygen consumption of C. digitalis declined gradually during desiccation at 15°C to about 60% of the undesiccated aerial control rate after 46 hours of exposure. During desiccation at 30°C the decline in oxygen consumption was much more pronounced. In C. pelta during desiccation at 15°C oxygen consumption progressively declined with increasing length of exposure to approximately 50% of control rates for the first 16 hours of exposure at which time rates became constant. At 30°C a more pronounced reduction in oxygen consumption occurred. Whole-body lactate accumulated in both species during desiccation at 15°C and 30°C in comparison with controls. At 15°C accumulation in C. pelta began after 15 hours of desiccation while at 30°C accumulations were evident after 4 hours. In contrast, C. digitalis gradually accumulated lactate during the entire length of exposure to desiccation conditions at 15°C. Upon exposure to moist nitrogen atmosphere both species exhibited a rapid bradycardia. Heart rates recovered rapidly after exposure and overshot pre-exposure rates indicating oxygen debt repayment. Of the three anaerobic end products examined (alanine, succinate and lactate) only lactate accumulated to any degree in either species during anoxia. During anoxia C. digitalis accumulated more lactate than C. pelta. C. pelta reached a maximum accumulation after 4 hours of anoxia while C. digitalis continued to accumulate lactate over the entire length of exposure to moist nitrogen. The results suggest differences between C. digitalis and C. pelta in metabolic adaptations which may be related to intertidal zonational differences. Title: Heart rate, survivorship, oxygen consumption, and metabolic end product accumulations in the intertidal limpets Collisella pelta and Collisella digitalis in relation to desiccation and hypoxia Author: Boese, Bruce Leon The heart rate, oxygen consumption, survivorship, and 1-lactate accumulation were determined in the intertidal limpets Collisella pelta and Collisella digitalis in relation to laboratory desiccation at 15°C or 30°C. Water loss was computed as a percentage of total initial body water (wet weight - dry weight). Although water was lost faster in C. digitalis than in C. pelta, C. digitalis tolerated more water loss and survived longer than C. pelta at both experimental temperatures. During the first few hours of desiccation at 15°C the heart rate of C. digitalis was constant while in C. pelta the heart rate declined rapidly. During desiccation at 30°C the heart rates of both species declined rapidly. No change was noted in control heart rates, determined under moist aerial conditions, in either species during a 40 hour exposure period. Oxygen consumption of C. digitalis declined gradually during desiccation at 15°C to about 60% of the undesiccated aerial control rate after 46 hours of exposure. During desiccation at 30°C the decline in oxygen consumption was much more pronounced. In C. pelta during desiccation at 15°C oxygen consumption progressively declined with increasing length of exposure to approximately 50% of control rates for the first 16 hours of exposure at which time rates became constant. At 30°C a more pronounced reduction in oxygen consumption occurred. Whole-body lactate accumulated in both species during desiccation at 15°C and 30°C in comparison with controls. At 15°C accumulation in C. pelta began after 15 hours of desiccation while at 30°C accumulations were evident after 4 hours. In contrast, C. digitalis gradually accumulated lactate during the entire length of exposure to desiccation conditions at 15°C. Upon exposure to moist nitrogen atmosphere both species exhibited a rapid bradycardia. Heart rates recovered rapidly after exposure and overshot pre-exposure rates indicating oxygen debt repayment. Of the three anaerobic end products examined (alanine, succinate and lactate) only lactate accumulated to any degree in either species during anoxia. During anoxia C. digitalis accumulated more lactate than C. pelta. C. pelta reached a maximum accumulation after 4 hours of anoxia while C. digitalis continued to accumulate lactate over the entire length of exposure to moist nitrogen. The results suggest differences between C. digitalis and C. pelta in metabolic adaptations which may be related to intertidal zonational differences. Close

• 42. [Article] An analysis of the population dynamics of selected avian species

  The impact that pesticides may have had on the mortality rates and productivity rates of non-game birds during the last 25 years was evaluated by studying the population dynamics of 16 species. A mathematical ...

  Citation × Citation Citation Abstract Copy Title: An analysis of the population dynamics of selected avian species Author: Henny, Charles J. The impact that pesticides may have had on the mortality rates and productivity rates of non-game birds during the last 25 years was evaluated by studying the population dynamics of 16 species. A mathematical model showing the relationships between population parameters that yielded stable populations was developed. The information needed for the model included: (1) mortality rate schedule (obtained from recoveries of banded birds), (2) productivity rates, and (3) the age of sexual maturity. Production requirements for a stable population and annual rate of change (increase or decrease) in population levels were estimated. Population parameters were compared to determine if changes had occurred between time periods (i.e, 1925-1945 vs. 1946-1965). The great horned owl, red-shouldered hawk, sparrow hawk, osprey, barn owl, Cooper's hawk, red-tailed hawk, great blue heron, black-crowned night heron, brown pelican, barn owl, chimney swift, blue jay, black-capped chickadee, cardinal, and robin were subjected to this analysis. No increase in post-fledging mortality rates in any of the species has occurred since 1945. Therefore, accelerated decline in the species studied must have resulted from lowered reproductive rates. Mortality rates have decreased in the Cooper's hawk, sparrow hawk, great blue heron, and brown pelican. A decrease in shooting pressure was associated with decreased mortality rates. Evidence of declining reproductive rates were found in the brown pelican, osprey, Cooper's hawk, red-shouldered hawk, and sparrow hawk. No changes in reproductive rates were noted in the red-tailed hawk, great horned owl, or barn owl. Information on productivity rates was not available for comparison with the other species although rates of productivity essential for a stable population were estimated. This work will provide the basis for making comparisons in future studies. No change in reproductive rates was apparent among species feeding primarily on mammals. Species exhibiting a lowered reproductive success since 1945 were those whose major food items consisted of fish, reptiles, amphibians, or birds. Lowered reproductive success was accompanied by a decrease in eggshell thickness. Other investigators have reported that sparrow hawks and mallard ducks fed a diet of DDE and dieldrin have produced thin eggshells under laboratory conditions, and exhibited a lower reproductive success. Many bird species which consume food in which chlorinated hydrocarbon pesticides have been concentrated through a series of transfers along food chains have declined. The chlorinated hydrocarbon pesticides are believed responsible. Title: An analysis of the population dynamics of selected avian species Author: Henny, Charles J. The impact that pesticides may have had on the mortality rates and productivity rates of non-game birds during the last 25 years was evaluated by studying the population dynamics of 16 species. A mathematical model showing the relationships between population parameters that yielded stable populations was developed. The information needed for the model included: (1) mortality rate schedule (obtained from recoveries of banded birds), (2) productivity rates, and (3) the age of sexual maturity. Production requirements for a stable population and annual rate of change (increase or decrease) in population levels were estimated. Population parameters were compared to determine if changes had occurred between time periods (i.e, 1925-1945 vs. 1946-1965). The great horned owl, red-shouldered hawk, sparrow hawk, osprey, barn owl, Cooper's hawk, red-tailed hawk, great blue heron, black-crowned night heron, brown pelican, barn owl, chimney swift, blue jay, black-capped chickadee, cardinal, and robin were subjected to this analysis. No increase in post-fledging mortality rates in any of the species has occurred since 1945. Therefore, accelerated decline in the species studied must have resulted from lowered reproductive rates. Mortality rates have decreased in the Cooper's hawk, sparrow hawk, great blue heron, and brown pelican. A decrease in shooting pressure was associated with decreased mortality rates. Evidence of declining reproductive rates were found in the brown pelican, osprey, Cooper's hawk, red-shouldered hawk, and sparrow hawk. No changes in reproductive rates were noted in the red-tailed hawk, great horned owl, or barn owl. Information on productivity rates was not available for comparison with the other species although rates of productivity essential for a stable population were estimated. This work will provide the basis for making comparisons in future studies. No change in reproductive rates was apparent among species feeding primarily on mammals. Species exhibiting a lowered reproductive success since 1945 were those whose major food items consisted of fish, reptiles, amphibians, or birds. Lowered reproductive success was accompanied by a decrease in eggshell thickness. Other investigators have reported that sparrow hawks and mallard ducks fed a diet of DDE and dieldrin have produced thin eggshells under laboratory conditions, and exhibited a lower reproductive success. Many bird species which consume food in which chlorinated hydrocarbon pesticides have been concentrated through a series of transfers along food chains have declined. The chlorinated hydrocarbon pesticides are believed responsible. Close

• 43. [Article] Riparian bird communities in Portland, Oregon : habitat, urbanization, and spatial scale patterns

  Urban ecosystems are characterized by human disturbance and changes in the amount, types, and spatial arrangement of wildlife habitat. The relative importance of habitat and human associated variables ...

  Citation × Citation Citation Abstract Copy Title: Riparian bird communities in Portland, Oregon : habitat, urbanization, and spatial scale patterns Author: Hennings, Lori A. Urban ecosystems are characterized by human disturbance and changes in the amount, types, and spatial arrangement of wildlife habitat. The relative importance of habitat and human associated variables to urban birds is unknown. In 1999, I surveyed spring bird and plant communities along 54 perennial streams in the Portland, Oregon metropolitan region. My objectives were to determine (1) what habitat and human-associated variables were related to avian community measures, (2) how far from riparian areas did relationships between avifauna and canopy cover and development extend, and (3) habitat characteristics associated with individual bird species. I used Principal Components Analysis to cluster and reduce the number of explanatory variables, and regressed bird community variables against the resulting principal components. Total and nonnative bird abundance were negatively related to the first principal component, PC 1 (high-scoring PC 1 sites had wide, structurally complex native forests) (r2 = 0.38, P < 0.0001 and r2 = 0.63, P < 0.0001, respectively). Several weak (r2 = 0.17-0.31, P < 0.003) curvilinear relationships emerged between overall and native species richness and diversity versus PC 1. Neotropical migratory bird (NMB) species richness and diversity were negatively related to human development variables, and positively related to native shrubs (adjusted r2 = 0.21 and 0.18, respectively; P < 0.003). I regressed bird community variables against canopy cover and street density for each of ten 50-m buffers around sites, then plotted the model fit (r) against buffer width. Native and nonnative abundance measures were negatively related to canopy cover. Total abundance was best predicted by canopy cover 300-350 m from the stream whereas normative abundance was predicted nearly equally by canopy cover in each buffer. The relationships between total species richness, native species richness, total diversity and native diversity were curvilinearly related to canopy cover, with canopy in the first 50 m appearing most important. Neotropical migratory bird species richness, diversity and abundance were negatively related to street density within 150 m of the stream. Brown-headed Cowbird (Molothrus ater) abundance was increasingly, negatively related to canopy cover as spatial scale increased. I used logistic regression to identify habitat and/or human-associated variables that predicted the occurrence of 32 species. The occurrence of four species (American Crow [Corvus brachyrhynchos], House Finch [Carpodacus mexicanus], Red-breasted Nuthatch [Sitta canadensis], and Vaux's Swift [Chaetura vauxi]) was positively, and five species (Black-headed Grosbeak [Pheucticus melanocephalus], Common Yellowthroat [Geothlypis trichas], Rufous Hummingbird [Selasphorus rufus], Steller's Jay [Cyanocitta setlleri], and Swainson's Thrush [Catharus ustulatus]) negatively related to human-associated variables. My results suggest that increasing urban canopy cover is the most valuable land management action for many breeding bird species. Preserving large undeveloped habitats and controlling urban sprawl may help prevent regional declines of NMB species. Title: Riparian bird communities in Portland, Oregon : habitat, urbanization, and spatial scale patterns Author: Hennings, Lori A. Urban ecosystems are characterized by human disturbance and changes in the amount, types, and spatial arrangement of wildlife habitat. The relative importance of habitat and human associated variables to urban birds is unknown. In 1999, I surveyed spring bird and plant communities along 54 perennial streams in the Portland, Oregon metropolitan region. My objectives were to determine (1) what habitat and human-associated variables were related to avian community measures, (2) how far from riparian areas did relationships between avifauna and canopy cover and development extend, and (3) habitat characteristics associated with individual bird species. I used Principal Components Analysis to cluster and reduce the number of explanatory variables, and regressed bird community variables against the resulting principal components. Total and nonnative bird abundance were negatively related to the first principal component, PC 1 (high-scoring PC 1 sites had wide, structurally complex native forests) (r2 = 0.38, P < 0.0001 and r2 = 0.63, P < 0.0001, respectively). Several weak (r2 = 0.17-0.31, P < 0.003) curvilinear relationships emerged between overall and native species richness and diversity versus PC 1. Neotropical migratory bird (NMB) species richness and diversity were negatively related to human development variables, and positively related to native shrubs (adjusted r2 = 0.21 and 0.18, respectively; P < 0.003). I regressed bird community variables against canopy cover and street density for each of ten 50-m buffers around sites, then plotted the model fit (r) against buffer width. Native and nonnative abundance measures were negatively related to canopy cover. Total abundance was best predicted by canopy cover 300-350 m from the stream whereas normative abundance was predicted nearly equally by canopy cover in each buffer. The relationships between total species richness, native species richness, total diversity and native diversity were curvilinearly related to canopy cover, with canopy in the first 50 m appearing most important. Neotropical migratory bird species richness, diversity and abundance were negatively related to street density within 150 m of the stream. Brown-headed Cowbird (Molothrus ater) abundance was increasingly, negatively related to canopy cover as spatial scale increased. I used logistic regression to identify habitat and/or human-associated variables that predicted the occurrence of 32 species. The occurrence of four species (American Crow [Corvus brachyrhynchos], House Finch [Carpodacus mexicanus], Red-breasted Nuthatch [Sitta canadensis], and Vaux's Swift [Chaetura vauxi]) was positively, and five species (Black-headed Grosbeak [Pheucticus melanocephalus], Common Yellowthroat [Geothlypis trichas], Rufous Hummingbird [Selasphorus rufus], Steller's Jay [Cyanocitta setlleri], and Swainson's Thrush [Catharus ustulatus]) negatively related to human-associated variables. My results suggest that increasing urban canopy cover is the most valuable land management action for many breeding bird species. Preserving large undeveloped habitats and controlling urban sprawl may help prevent regional declines of NMB species. Close

• 44. [Article] Using remote sensing, in situ observations, and geographic information systems to map benthic habitats at Heceta Bank, Oregon

  Dramatic declines in many species of demersal fishes off the West Coast have resulted in the designation of nine commercially important species as being overfished. While the causes of those declines are ...

  Citation × Citation Citation Abstract Copy Title: Using remote sensing, in situ observations, and geographic information systems to map benthic habitats at Heceta Bank, Oregon Author: Whitmire, Curt E. Dramatic declines in many species of demersal fishes off the West Coast have resulted in the designation of nine commercially important species as being overfished. While the causes of those declines are not clearly understood, the fact remains that a paucity of life history and abundance data exists for many demersal species, also known as groundfish. Due to this uncertainty, only 21 of the 82 species of groundfish managed under the Groundfish Fishery Management Plan of the Pacific Fishery Management Council (PFMC) have been fully assessed. One challenge in designing a systematic survey of groundfish resources is that many species associate with heterogeneous substrate of varying relief. In many areas, the rugosity of the substrata precludes sampling by conventional techniques (e.g. bottom trawl gear). This has stimulated research that characterizes fish-habitat associations for use in design of new survey methodology. Using a combination of remote sensing, in situ observations, and spatial analytical techniques, four benthic habitat classes were mapped for a large rocky bank off the central Oregon coast known as Heceta Bank. Observational data from human-occupied submersible and remotely operated vehicle dives in the late 1980s, 2000 and 2001 were used to establish habitat classes with specific substrate characteristics that have been statistically shown to correlate with demersal fish distributions. The observational habitat data was then extrapolated over the extent of a multibeam sonar survey conducted in 1998 using quantitative parameters derived from high-resolution bathymetric and backscatter imagery of the seafloor. The resultant map predicts the locations of four habitat classes: Ridge-Gully, High-Relief Rock (boulders, cobbles), Unconsolidated Sediment 1 (muds), and Unconsolidated Sediment 2 (sands). The main utility of the habitat map developed as part of the current study is that it provides a context for analyses of a variety of spatial data. For instance, habitat data provides one additional spatial component besides depth and latitude that can be used to stratify catch per unit effort data from surveys and commercial logbooks. Also, essential fish habitat for many demersal species can now be identified in more detail. Finally, habitat data like those presented here can aid in the design of marine reserves and protected areas by providing a context for spatial analyses of data of ecological importance. Title: Using remote sensing, in situ observations, and geographic information systems to map benthic habitats at Heceta Bank, Oregon Author: Whitmire, Curt E. Dramatic declines in many species of demersal fishes off the West Coast have resulted in the designation of nine commercially important species as being overfished. While the causes of those declines are not clearly understood, the fact remains that a paucity of life history and abundance data exists for many demersal species, also known as groundfish. Due to this uncertainty, only 21 of the 82 species of groundfish managed under the Groundfish Fishery Management Plan of the Pacific Fishery Management Council (PFMC) have been fully assessed. One challenge in designing a systematic survey of groundfish resources is that many species associate with heterogeneous substrate of varying relief. In many areas, the rugosity of the substrata precludes sampling by conventional techniques (e.g. bottom trawl gear). This has stimulated research that characterizes fish-habitat associations for use in design of new survey methodology. Using a combination of remote sensing, in situ observations, and spatial analytical techniques, four benthic habitat classes were mapped for a large rocky bank off the central Oregon coast known as Heceta Bank. Observational data from human-occupied submersible and remotely operated vehicle dives in the late 1980s, 2000 and 2001 were used to establish habitat classes with specific substrate characteristics that have been statistically shown to correlate with demersal fish distributions. The observational habitat data was then extrapolated over the extent of a multibeam sonar survey conducted in 1998 using quantitative parameters derived from high-resolution bathymetric and backscatter imagery of the seafloor. The resultant map predicts the locations of four habitat classes: Ridge-Gully, High-Relief Rock (boulders, cobbles), Unconsolidated Sediment 1 (muds), and Unconsolidated Sediment 2 (sands). The main utility of the habitat map developed as part of the current study is that it provides a context for analyses of a variety of spatial data. For instance, habitat data provides one additional spatial component besides depth and latitude that can be used to stratify catch per unit effort data from surveys and commercial logbooks. Also, essential fish habitat for many demersal species can now be identified in more detail. Finally, habitat data like those presented here can aid in the design of marine reserves and protected areas by providing a context for spatial analyses of data of ecological importance. Close

• 45. [Article] Patch dynamics of desert fishes in the arid wetlands of western Utah

  The conservation of declining desert fish species requires the identification of relations between fish population dynamics and their environments. Dynamic occupancy modeling, an approach that requires ...

  Citation × Citation Citation Abstract Copy Title: Patch dynamics of desert fishes in the arid wetlands of western Utah Author: Sáenz, Jessica The conservation of declining desert fish species requires the identification of relations between fish population dynamics and their environments. Dynamic occupancy modeling, an approach that requires less information than traditional mark-recapture studies, may help identify important factors affecting population processes and aid desert fish conservation and restoration efforts. I used dynamic multi-season occupancy models for two analyses (multi-state and multi-species) to evaluate the influence of patch-level characteristics (patch percent open water, average patch depth, patch area), grazing damage, species interactions, population differences, patch connectivity and environmental variation (seasonal precipitation and temperature) on the patch dynamics (colonization, persistence, reproduction) of two desert chub species found in Snake Valley, UT. My results indicate that there was the strongest evidence according to model weights that patch dynamics in this system were influenced by patch-level characteristics (patch percent open water and average patch depth), grazing damage, population differences, biotic interactions, and winter precipitation rather than landscape level features such as connectivity. I observed positive effects of patch percent open water and average patch depth on least chub and Utah chub persistence. I also found that grazing damage increased their persistence at the medium damage level but decreased least chub and Utah chub colonization at the high grazing damage level. Least chub and Utah chub colonization varied between the two populations (study areas) with a higher probability of colonization at Bishop Springs than at Gandy Salt Marsh. In addition, I found some evidence that biotic interactions between least chub and Utah chub may be occurring in this system. Least chub were less likely to colonize patches previously occupied by Utah chub but surprisingly there was little evidence that these species interactions affected least chub persistence. Least chub reproduction increased with winter precipitation and was higher at Gandy Salt Marsh than Bishop Springs. The use of dynamic occupancy modeling in desert spring wetland complexes may provide a valuable tool for managers tasked with conserving at-risk desert fish species. Title: Patch dynamics of desert fishes in the arid wetlands of western Utah Author: Sáenz, Jessica The conservation of declining desert fish species requires the identification of relations between fish population dynamics and their environments. Dynamic occupancy modeling, an approach that requires less information than traditional mark-recapture studies, may help identify important factors affecting population processes and aid desert fish conservation and restoration efforts. I used dynamic multi-season occupancy models for two analyses (multi-state and multi-species) to evaluate the influence of patch-level characteristics (patch percent open water, average patch depth, patch area), grazing damage, species interactions, population differences, patch connectivity and environmental variation (seasonal precipitation and temperature) on the patch dynamics (colonization, persistence, reproduction) of two desert chub species found in Snake Valley, UT. My results indicate that there was the strongest evidence according to model weights that patch dynamics in this system were influenced by patch-level characteristics (patch percent open water and average patch depth), grazing damage, population differences, biotic interactions, and winter precipitation rather than landscape level features such as connectivity. I observed positive effects of patch percent open water and average patch depth on least chub and Utah chub persistence. I also found that grazing damage increased their persistence at the medium damage level but decreased least chub and Utah chub colonization at the high grazing damage level. Least chub and Utah chub colonization varied between the two populations (study areas) with a higher probability of colonization at Bishop Springs than at Gandy Salt Marsh. In addition, I found some evidence that biotic interactions between least chub and Utah chub may be occurring in this system. Least chub were less likely to colonize patches previously occupied by Utah chub but surprisingly there was little evidence that these species interactions affected least chub persistence. Least chub reproduction increased with winter precipitation and was higher at Gandy Salt Marsh than Bishop Springs. The use of dynamic occupancy modeling in desert spring wetland complexes may provide a valuable tool for managers tasked with conserving at-risk desert fish species. Close

• 46. [Article] 2007 Oregon Chub Investigations Progress Reports 2007

  Abstract -- Oregon chub Oregonichthys crameri, small minnows endemic to the Willamette Valley, were federally listed as endangered under the Endangered Species Act in 1993. Factors implicated in the decline ...

  Citation × Citation Citation Abstract Copy Title: 2007 Oregon Chub Investigations Progress Reports 2007 Abstract -- Oregon chub Oregonichthys crameri, small minnows endemic to the Willamette Valley, were federally listed as endangered under the Endangered Species Act in 1993. Factors implicated in the decline of this species include changes in flow regimes and habitat characteristics resulting from the construction of flood control dams, revetments, channelization, diking, and the drainage of wetlands. The Oregon chub is further threatened by predation and competition by non-native species such as largemouth bass Micropterus salmoides, crappies Pomoxis sp., sunfishes Lepomis sp., bullheads Ameiurus sp., and western mosquitofish Gambusia affinis. We continued surveys initiated in 1991 in the Willamette River drainage to quantify the abundance of known Oregon chub populations, search for unknown populations, evaluate potential introduction sites, and monitor introduced populations as part of the implementation of the Oregon Chub Recovery Plan. We sampled a total of 70 sites in 2007. New populations of Oregon chub were discovered at Green Island in the lower McKenzie River and in the Muddy Creek drainage (Linn County). We confirmed the continued existence of Oregon chub at 34 locations. These included 23 naturally occurring and 11 introduced populations. We did not find Oregon chub at nine locations where they were collected on at least one occasion between 1991-2006. Nonnative fish were collected at most of these locations. We obtained abundance estimates of 18 naturally occurring populations and 11 introduced populations of Oregon chub located in the Middle Fork Willamette, Santiam, McKenzie, and Mid-Willamette drainages (Table 1). We introduced additional Oregon chub into the South Stayton Pond in the Santiam drainage and into Cheadle and Display Ponds in the Mid-Willamette drainage. The Oregon Chub Recovery Plan (U.S. Fish and Wildlife Service 1998) set recovery criteria for downlisting the species to “threatened” and for delisting the species. The criteria for downlisting the species are: 1) establish and manage 10 populations of at least 500 adult fish, 2) all of these populations must exhibit a stable or increasing trend for five years, and 3) at least three populations meeting criterion 1 and 2 must be located in each of the three recovery areas (Middle Fork Willamette River, Santiam River, and Mid-Willamette River tributaries). In 2007, there were 20 populations totaling 500 or more individuals (Table 1). Fifteen of these populations also met the second criteria. Of the 15 populations meeting criteria 1 and 2, eight were located in the Middle Fork Willamette drainage, four were located in the Mid-Willamette drainage, and three were located in the Santiam drainage. In 2007, we met the downlisting criteria. Findings to date indicate that Oregon chub remain at risk due to the loss of suitable habitat and the continued threats posed by the proliferation of non-native fishes, illegal water withdrawals, accelerated sedimentation, and potential chemical spills or careless pesticide applications. Their status has improved in recent years, resulting primarily from successful introductions and the discovery of previously undocumented populations. Title: 2007 Oregon Chub Investigations Progress Reports 2007 Abstract -- Oregon chub Oregonichthys crameri, small minnows endemic to the Willamette Valley, were federally listed as endangered under the Endangered Species Act in 1993. Factors implicated in the decline of this species include changes in flow regimes and habitat characteristics resulting from the construction of flood control dams, revetments, channelization, diking, and the drainage of wetlands. The Oregon chub is further threatened by predation and competition by non-native species such as largemouth bass Micropterus salmoides, crappies Pomoxis sp., sunfishes Lepomis sp., bullheads Ameiurus sp., and western mosquitofish Gambusia affinis. We continued surveys initiated in 1991 in the Willamette River drainage to quantify the abundance of known Oregon chub populations, search for unknown populations, evaluate potential introduction sites, and monitor introduced populations as part of the implementation of the Oregon Chub Recovery Plan. We sampled a total of 70 sites in 2007. New populations of Oregon chub were discovered at Green Island in the lower McKenzie River and in the Muddy Creek drainage (Linn County). We confirmed the continued existence of Oregon chub at 34 locations. These included 23 naturally occurring and 11 introduced populations. We did not find Oregon chub at nine locations where they were collected on at least one occasion between 1991-2006. Nonnative fish were collected at most of these locations. We obtained abundance estimates of 18 naturally occurring populations and 11 introduced populations of Oregon chub located in the Middle Fork Willamette, Santiam, McKenzie, and Mid-Willamette drainages (Table 1). We introduced additional Oregon chub into the South Stayton Pond in the Santiam drainage and into Cheadle and Display Ponds in the Mid-Willamette drainage. The Oregon Chub Recovery Plan (U.S. Fish and Wildlife Service 1998) set recovery criteria for downlisting the species to “threatened” and for delisting the species. The criteria for downlisting the species are: 1) establish and manage 10 populations of at least 500 adult fish, 2) all of these populations must exhibit a stable or increasing trend for five years, and 3) at least three populations meeting criterion 1 and 2 must be located in each of the three recovery areas (Middle Fork Willamette River, Santiam River, and Mid-Willamette River tributaries). In 2007, there were 20 populations totaling 500 or more individuals (Table 1). Fifteen of these populations also met the second criteria. Of the 15 populations meeting criteria 1 and 2, eight were located in the Middle Fork Willamette drainage, four were located in the Mid-Willamette drainage, and three were located in the Santiam drainage. In 2007, we met the downlisting criteria. Findings to date indicate that Oregon chub remain at risk due to the loss of suitable habitat and the continued threats posed by the proliferation of non-native fishes, illegal water withdrawals, accelerated sedimentation, and potential chemical spills or careless pesticide applications. Their status has improved in recent years, resulting primarily from successful introductions and the discovery of previously undocumented populations. Close

• 47. [Article] Habitat selection by Greater Sage-Grouse during winter in southeastern Oregon

  This is the publisher’s final pdf. The published article is copyrighted by Brigham Young University and can be found at: https://ojs.lib.byu.edu/wnan/index.php/wnan/. To the best of our knowledge, one ...

  Citation × Citation Citation Abstract Copy Title: Habitat selection by Greater Sage-Grouse during winter in southeastern Oregon Author: Hagen, Christian A., Glenn, Elizabeth M., Anthony, Robert G., Willis, Mitchell J. This is the publisher’s final pdf. The published article is copyrighted by Brigham Young University and can be found at: https://ojs.lib.byu.edu/wnan/index.php/wnan/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Habitat selection by Greater Sage-Grouse during winter in southeastern Oregon Author: Hagen, Christian A., Glenn, Elizabeth M., Anthony, Robert G., Willis, Mitchell J. This is the publisher’s final pdf. The published article is copyrighted by Brigham Young University and can be found at: https://ojs.lib.byu.edu/wnan/index.php/wnan/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 48. [Article] Habitat Selection by Greater Sage-Grouse During Winter in Southeastern Oregon

  This is the publisher’s final pdf. The published article is copyrighted by Brigham Young University, Monte L Bean Life Science Museau and can be found at: https://ojs.lib.byu.edu/spc/index.php/wnan

  Citation × Citation Citation Abstract Copy Title: Habitat Selection by Greater Sage-Grouse During Winter in Southeastern Oregon Author: Hagen, Christian A., Glenn, Elizabeth M., Anthony, Robert G., Willis, Mitchell J. This is the publisher’s final pdf. The published article is copyrighted by Brigham Young University, Monte L Bean Life Science Museau and can be found at: https://ojs.lib.byu.edu/spc/index.php/wnan Title: Habitat Selection by Greater Sage-Grouse During Winter in Southeastern Oregon Author: Hagen, Christian A., Glenn, Elizabeth M., Anthony, Robert G., Willis, Mitchell J. This is the publisher’s final pdf. The published article is copyrighted by Brigham Young University, Monte L Bean Life Science Museau and can be found at: https://ojs.lib.byu.edu/spc/index.php/wnan Close

• 49. [Article] Performance of Willamette Valley native plants following herbicide exposure

  Prairies were once the dominant vegetation type in Oregon's Willamette Valley. Land use conversion, fire suppression, succession, and invasive species have reduced Willamette Valley prairies to less than ...

  Citation × Citation Citation Abstract Copy Title: Performance of Willamette Valley native plants following herbicide exposure Author: Blakeley-Smith, Matthew R. Prairies were once the dominant vegetation type in Oregon's Willamette Valley. Land use conversion, fire suppression, succession, and invasive species have reduced Willamette Valley prairies to less than 1% of their historical area. The remnant prairies that persist today are small in size and are highly fragmented. Marginal strips of habitat along roadsides and agricultural fields play an important role as refugia for native species and provide important resources for wildlife. These seemingly insignificant habitat units may also play an important role in facilitating gene flow between disjunct populations of prairie plants, thus reducing the potential for the negative effects of inbreeding depression. Presently, much of the land area in the Willamette Valley is dedicated to commercial agricultural which is heavily reliant on herbicides for weed control and field preparation. Since herbicide applications are imprecise and prone to drift, there is potential to impact the native plants surrounding these agricultural fields. Current EPA methods for assessing the ecological effects of herbicides may not be robust enough to account for potential impacts on native plants since the suggested test species are ten annual agricultural crops. To address the need for improved phytotoxicity testing protocols, we incorporated non-crop plant species into the EPA vegetative vigor test methodology for use in determining effects of low concentrations of chemical herbicides on Willamette Valley terrestrial plants. A separate experiment was conducted in order to determine how herbicides might be used to restore Butterfly Meadows, a degraded Willamette Valley prairie. The specific objective of this study were to: 1.) determine which herbicide treatments were most effective at reducing dominance of an invasive species, Brachypodium sylvaticum, 2.) determine if native species declined following herbicide treatments, and 3.) describe the compositional changes in the plant communities over a four-year period. The EPA vegetative vigor test study showed that there was a wide variety of responses among 17 species (14 native and 3 introduced) to each herbicide tested (glyphosate, tribenuron, and fluazifop). For glyphosate, Potentilla gracilis was the most sensitive species based on an EC25 value of 0.012 x f.a.r. for dry weight; while Bromus carinatus, Clarkia amoena, Gilia capitata, and Lupinus albicaulis were tolerant to glyphosate as indicated by no effect on dry weight. Seven Willamette Valley forb species were sensitive to tribenuron based on EC25 values ranging from 0.001 to 0.012 x f.a.r.; Clarkia amoena, Collinsia grandflora, Leucanthemum vulgare, Potentilla gracilis, Prunella vulgaris, Ranunculus occidentalis and Sanquisorba occidentalis. Six grass species and Eriophyllum lanatum were resistant to tribenuron showing no reduction in dry weight. Fluazifop primarily affected grass species as expected due to the grass-specific activity for this herbicide. Two native grasses, Elymus trachycaulus and Danthonia californica were the most sensitive to fluazifop, based on low EC25 values of 0.002 to 0.010 x f.a.r. A native fescue grass, Festuca roemeri, and nearly all the forb species were resistant to fluazifop, showing no response at any herbicide rate applied. The results from this research will be useful as background information for evaluating potential modifications in the EPA's Vegetative Vigor Test to assess the risk of herbicides to non-target plants. Seven different herbicide combinations were effective at reducing the cover of Brachypodium sylvaticum in test plots at Butterfly Meadows one year after treatment. The reduction of B. sylvaticum was short lived however, since the cover of this grass species was not different from control plots during the second growing season. Native plant species were not negatively impacted by the herbicide treatments, as shown by MRPP analysis. Successional trajectories illustrate that control plots that were dominated by B. sylvaticum remained relatively unchanged over the course of four years. Some treatments exhibited a sharp decline in dominance by graminoids after the first year, a recovery the second year, but never returned exactly to their pretreatment community composition after the third year. The reduction of the dominant species after the first growing season was associated with colonization by a number of introduced species into the newly created open habitat. Over the same period there was no overall increase in native species cover, suggesting that the native species at this site may be recruitment limited. Future restoration activities at this site should include multiple years of B. sylvaticum control, with special attention to the seed bank and tolerant individuals. Seed additions of native species may help fill empty niches and afford resistance to invasion by introduced species. Title: Performance of Willamette Valley native plants following herbicide exposure Author: Blakeley-Smith, Matthew R. Prairies were once the dominant vegetation type in Oregon's Willamette Valley. Land use conversion, fire suppression, succession, and invasive species have reduced Willamette Valley prairies to less than 1% of their historical area. The remnant prairies that persist today are small in size and are highly fragmented. Marginal strips of habitat along roadsides and agricultural fields play an important role as refugia for native species and provide important resources for wildlife. These seemingly insignificant habitat units may also play an important role in facilitating gene flow between disjunct populations of prairie plants, thus reducing the potential for the negative effects of inbreeding depression. Presently, much of the land area in the Willamette Valley is dedicated to commercial agricultural which is heavily reliant on herbicides for weed control and field preparation. Since herbicide applications are imprecise and prone to drift, there is potential to impact the native plants surrounding these agricultural fields. Current EPA methods for assessing the ecological effects of herbicides may not be robust enough to account for potential impacts on native plants since the suggested test species are ten annual agricultural crops. To address the need for improved phytotoxicity testing protocols, we incorporated non-crop plant species into the EPA vegetative vigor test methodology for use in determining effects of low concentrations of chemical herbicides on Willamette Valley terrestrial plants. A separate experiment was conducted in order to determine how herbicides might be used to restore Butterfly Meadows, a degraded Willamette Valley prairie. The specific objective of this study were to: 1.) determine which herbicide treatments were most effective at reducing dominance of an invasive species, Brachypodium sylvaticum, 2.) determine if native species declined following herbicide treatments, and 3.) describe the compositional changes in the plant communities over a four-year period. The EPA vegetative vigor test study showed that there was a wide variety of responses among 17 species (14 native and 3 introduced) to each herbicide tested (glyphosate, tribenuron, and fluazifop). For glyphosate, Potentilla gracilis was the most sensitive species based on an EC25 value of 0.012 x f.a.r. for dry weight; while Bromus carinatus, Clarkia amoena, Gilia capitata, and Lupinus albicaulis were tolerant to glyphosate as indicated by no effect on dry weight. Seven Willamette Valley forb species were sensitive to tribenuron based on EC25 values ranging from 0.001 to 0.012 x f.a.r.; Clarkia amoena, Collinsia grandflora, Leucanthemum vulgare, Potentilla gracilis, Prunella vulgaris, Ranunculus occidentalis and Sanquisorba occidentalis. Six grass species and Eriophyllum lanatum were resistant to tribenuron showing no reduction in dry weight. Fluazifop primarily affected grass species as expected due to the grass-specific activity for this herbicide. Two native grasses, Elymus trachycaulus and Danthonia californica were the most sensitive to fluazifop, based on low EC25 values of 0.002 to 0.010 x f.a.r. A native fescue grass, Festuca roemeri, and nearly all the forb species were resistant to fluazifop, showing no response at any herbicide rate applied. The results from this research will be useful as background information for evaluating potential modifications in the EPA's Vegetative Vigor Test to assess the risk of herbicides to non-target plants. Seven different herbicide combinations were effective at reducing the cover of Brachypodium sylvaticum in test plots at Butterfly Meadows one year after treatment. The reduction of B. sylvaticum was short lived however, since the cover of this grass species was not different from control plots during the second growing season. Native plant species were not negatively impacted by the herbicide treatments, as shown by MRPP analysis. Successional trajectories illustrate that control plots that were dominated by B. sylvaticum remained relatively unchanged over the course of four years. Some treatments exhibited a sharp decline in dominance by graminoids after the first year, a recovery the second year, but never returned exactly to their pretreatment community composition after the third year. The reduction of the dominant species after the first growing season was associated with colonization by a number of introduced species into the newly created open habitat. Over the same period there was no overall increase in native species cover, suggesting that the native species at this site may be recruitment limited. Future restoration activities at this site should include multiple years of B. sylvaticum control, with special attention to the seed bank and tolerant individuals. Seed additions of native species may help fill empty niches and afford resistance to invasion by introduced species. Close

• 50. [Article] Contrasting distribution patterns of invasive and naturalized non-native species along environmental gradients in a semi-arid montane 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 article is copyrighted by International Association ...

  Citation × Citation Citation Abstract Copy Title: Contrasting distribution patterns of invasive and naturalized non-native species along environmental gradients in a semi-arid montane ecosystem Author: Andersen, Kelly M., Endress, Bryan A., Parks, Catherine G., Naylor, Bridgett J. 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 article is copyrighted by International Association for Vegetation Science and published by John Wiley & Sons, Ltd.. It can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291654-109X Title: Contrasting distribution patterns of invasive and naturalized non-native species along environmental gradients in a semi-arid montane ecosystem Author: Andersen, Kelly M., Endress, Bryan A., Parks, Catherine G., Naylor, Bridgett J. 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 article is copyrighted by International Association for Vegetation Science and published by John Wiley & Sons, Ltd.. It can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291654-109X Close