Search

Search Results

• 11. [Article] Relative abundance and habitat associations of small mammals in two forest types in southern Oregon

  I studied small-mammal communities and their response to grazing in mixed-conifer forests and oak woodlands in the Cascade-Siskiyou National Monument in southern Oregon. My objectives were to (1) compare ...

  Citation × Citation Citation Abstract Copy Title: Relative abundance and habitat associations of small mammals in two forest types in southern Oregon Author: Johnston, Aaron N. I studied small-mammal communities and their response to grazing in mixed-conifer forests and oak woodlands in the Cascade-Siskiyou National Monument in southern Oregon. My objectives were to (1) compare small-mammal communities among forest types and grazing intensities, (2) identify riparian affiliated species, and (3) describe microhabitat associations. Over two years, I trapped 1,617 individual small mammals representing 20 species. Mixed-conifer forests had more species and greater abundances of small mammals than oak woodlands, but there were no significant differences between the forest types in species richness or diversity at the stand level, as most sites had 3 to 5 species at any given time. Evenness was higher in oak woodlands compared to mixed-conifer forests because of lower dominance by Peromyscus maniculatus and fewer rare species. P. maniculatus dominated both forest types. Neurotrichus gibbsii, Tamias amoenus, Tamias siskiyou, Neotoma cinerea, Clethrionomys californicus, Microtus californicus, Microtus longicaudus, and Microtus montanus were found only in mixed-conifer forests, whereas Peromyscus boylii were trapped exclusively in oak woodlands. Although the two forest types shared 10 species, Sorex trowbridgii and Peromyscus maniculatus were significantly (P < 0.05) more abundant in mixed-conifer forests, whereas Sorex vagrans, Reithrodontomys megalotis, Peromyscus truei, and Neotoma fuscipes were significantly more abundant in oak woodlands. Microtus townsendii was the only species that was equally abundant in both forest types, but was found exclusively within meadow sites in mixed-conifer forests. I found no significant differences in species richness, diversity, and evenness between heavy and lightly grazed sites. However, mean mammalian biomass was 138 g/ha lower in heavily grazed sites, and abundances were 89.3% of those in lightly grazed sites. Cumulative biomass and abundance across heavily grazed sites were 65% and 80%, respectively, of that in lightly grazed sites. Several relatively large species (e.g. Neotoma spp. and Microtus spp.) were less abundant or absent in heavily grazed sites. My results support previous studies that found lower abundances of small mammals associated with herbaceous cover (e.g. Microtus spp.) in heavily grazed sites and little or no effect for species associated with open habitats (e.g. Tamias spp.). I found significantly (P < 0.05) lower abundances of S. trowbridgii (conifer), Peromyscus spp. (oak), N. cinerea (conifer), N. fuscipes (oak), M. longicaudus (conifer), and M. californicus (conifer) in heavy versus lightly grazed sites. There were also fewer T. siskiyou, R. megalotis, and M. townsendii captured in heavy versus lightly grazed sites, but the differences were not significant (P > 0.05). S. vagrans and T. amoenus were significantly more abundant in heavily grazed sites. Sample sizes for the remaining species were too small for comparison (n < 6). N. gibbsii, C. californicus, and M. californicus were captured exclusively in lightly grazed sites; only T. amoenus was captured exclusively in a heavily grazed site. There was a significant (P < 0.05) decrease in the odds of catching R. megalotis, N. cinerea, N. fuscipes, and M. longicaudus on heavy versus lightly grazed sites after accounting for microhabitat associations and potential confounding factors. Odds of capture were significantly (P < 0.05) lower for P. maniculatus in heavy versus lightly grazed sites in oak woodlands, but there was less difference in abundance between grazing intensities in mixed-conifer forests. There was some evidence to suggest that grazing decreased the odds of capturing M. townsendii in riparian areas. Although I found significantly (P < 0.05) fewer S. trowbridgii in heavily grazed sites, my analysis indicated that microhabitat associations rather than grazing explained the difference. Grazing appeared to increase the use of riparian areas by Tamias spp. by removing herbaceous cover and increasing bare ground. I described microhabitat associations for 10 species and found a suite of species (S. trowbridgii, T. amoenus, T. siskiyou, N. cinerea) that were positively associated with coarse woody debris and/or snags. R. megalotis, M. longicaudus, and M. townsendii were affiliated with, but not obligated, to riparian areas. P. maniculatus were ubiquitous, but abundances were also higher in riparian areas compared with uplands. T. siskiyou and P. truei appeared to be associated with uplands rather than riparian areas. Although I captured few S. vagrans, N. gibbsii, M. californicus, and M. montanus, they were found in either riparian areas or around spring seeps, which support previous studies. My results supported the importance of riparian areas to small mammals as suggested by previous studies. Title: Relative abundance and habitat associations of small mammals in two forest types in southern Oregon Author: Johnston, Aaron N. I studied small-mammal communities and their response to grazing in mixed-conifer forests and oak woodlands in the Cascade-Siskiyou National Monument in southern Oregon. My objectives were to (1) compare small-mammal communities among forest types and grazing intensities, (2) identify riparian affiliated species, and (3) describe microhabitat associations. Over two years, I trapped 1,617 individual small mammals representing 20 species. Mixed-conifer forests had more species and greater abundances of small mammals than oak woodlands, but there were no significant differences between the forest types in species richness or diversity at the stand level, as most sites had 3 to 5 species at any given time. Evenness was higher in oak woodlands compared to mixed-conifer forests because of lower dominance by Peromyscus maniculatus and fewer rare species. P. maniculatus dominated both forest types. Neurotrichus gibbsii, Tamias amoenus, Tamias siskiyou, Neotoma cinerea, Clethrionomys californicus, Microtus californicus, Microtus longicaudus, and Microtus montanus were found only in mixed-conifer forests, whereas Peromyscus boylii were trapped exclusively in oak woodlands. Although the two forest types shared 10 species, Sorex trowbridgii and Peromyscus maniculatus were significantly (P < 0.05) more abundant in mixed-conifer forests, whereas Sorex vagrans, Reithrodontomys megalotis, Peromyscus truei, and Neotoma fuscipes were significantly more abundant in oak woodlands. Microtus townsendii was the only species that was equally abundant in both forest types, but was found exclusively within meadow sites in mixed-conifer forests. I found no significant differences in species richness, diversity, and evenness between heavy and lightly grazed sites. However, mean mammalian biomass was 138 g/ha lower in heavily grazed sites, and abundances were 89.3% of those in lightly grazed sites. Cumulative biomass and abundance across heavily grazed sites were 65% and 80%, respectively, of that in lightly grazed sites. Several relatively large species (e.g. Neotoma spp. and Microtus spp.) were less abundant or absent in heavily grazed sites. My results support previous studies that found lower abundances of small mammals associated with herbaceous cover (e.g. Microtus spp.) in heavily grazed sites and little or no effect for species associated with open habitats (e.g. Tamias spp.). I found significantly (P < 0.05) lower abundances of S. trowbridgii (conifer), Peromyscus spp. (oak), N. cinerea (conifer), N. fuscipes (oak), M. longicaudus (conifer), and M. californicus (conifer) in heavy versus lightly grazed sites. There were also fewer T. siskiyou, R. megalotis, and M. townsendii captured in heavy versus lightly grazed sites, but the differences were not significant (P > 0.05). S. vagrans and T. amoenus were significantly more abundant in heavily grazed sites. Sample sizes for the remaining species were too small for comparison (n < 6). N. gibbsii, C. californicus, and M. californicus were captured exclusively in lightly grazed sites; only T. amoenus was captured exclusively in a heavily grazed site. There was a significant (P < 0.05) decrease in the odds of catching R. megalotis, N. cinerea, N. fuscipes, and M. longicaudus on heavy versus lightly grazed sites after accounting for microhabitat associations and potential confounding factors. Odds of capture were significantly (P < 0.05) lower for P. maniculatus in heavy versus lightly grazed sites in oak woodlands, but there was less difference in abundance between grazing intensities in mixed-conifer forests. There was some evidence to suggest that grazing decreased the odds of capturing M. townsendii in riparian areas. Although I found significantly (P < 0.05) fewer S. trowbridgii in heavily grazed sites, my analysis indicated that microhabitat associations rather than grazing explained the difference. Grazing appeared to increase the use of riparian areas by Tamias spp. by removing herbaceous cover and increasing bare ground. I described microhabitat associations for 10 species and found a suite of species (S. trowbridgii, T. amoenus, T. siskiyou, N. cinerea) that were positively associated with coarse woody debris and/or snags. R. megalotis, M. longicaudus, and M. townsendii were affiliated with, but not obligated, to riparian areas. P. maniculatus were ubiquitous, but abundances were also higher in riparian areas compared with uplands. T. siskiyou and P. truei appeared to be associated with uplands rather than riparian areas. Although I captured few S. vagrans, N. gibbsii, M. californicus, and M. montanus, they were found in either riparian areas or around spring seeps, which support previous studies. My results supported the importance of riparian areas to small mammals as suggested by previous studies. Close

• 12. [Article] Some factors controlling the establishment and distribution of Quercus agrifolia Nee and Q. engelmannii Greene in certain southern California oak woodlands

  The structure of two oak woodland types in the Santa Rosa region of the Santa Ana Mountains of southern California has been described by Zuill (1967). One type called the grass oak woodland (GOW) is composed ...

  Citation × Citation Citation Abstract Copy Title: Some factors controlling the establishment and distribution of Quercus agrifolia Nee and Q. engelmannii Greene in certain southern California oak woodlands Author: Snow, Gerald Eldon The structure of two oak woodland types in the Santa Rosa region of the Santa Ana Mountains of southern California has been described by Zuill (1967). One type called the grass oak woodland (GOW) is composed mainly of Q. engelmannii on hills and slopes. The other type called the dense oak woodland (DOW) is composed equally of Q. engelmannii and Q. agrifolia with twice the density of the GOW and is located in valleys with granite rock outcrops. An apparent lack of seedlings and saplings was noted in the area. The present study focuses on an explanation for the distribution patterns of the two oak species in the field and the factors which might be most important in influencing seedling establishment. Quercus agrifolia is restricted to cool moist protected locations on the north side and in fractures of rock outcrops because its acorns are sensitive to moisture loss on air drying, require constantly moist conditions for one to five weeks for water uptake to effect germination and have very rapid shoot development after germination. Seedlings may be intolerant of high temperatures in open grass litter, and seedlings and saplings appear less tolerant of fire than Q. engelmannii, which would also tend to restrict Q. agrifolia to protected locations around rock outcrops. The distribution of Q. engelmannii trees with respect to rock outcrops does not differ from a random distribution and the few that are associated with outcrops show a random distribution with respect to position around outcrops. The occurrence of Q. engelmannii in more open exposed habitats may be due to its acorns' tolerance to moisture loss on air drying, their ability to germinate with little or n6 additional water uptake, its self-planting mechanism and delayed shoot development, and the drought deciduous habit of seedlings and their tolerance to fire. In the laboratory the drought capable of killing 50% of the seedlings is about 100 bars soil moisture tension for Q. engelmannii and about 250 bars for Q. agrifolia. The survival of Q. agrifolia under a greater degree of soil drought is mainly attributable to its higher root: shoot ratio under these particular conditions. Seedlings of both species would be expected to survive any drought recorded in the field between 1968 and 1970 at their expected rooting depth. After a very wet rainy season none of the mature trees experienced any moisture stress by the end of the dry season even though the near surface soils were quite dry. After a quite dry year trees in the DOW showed significantly greater moisture stress than those on a hilltop in the GOW. The moisture stress measurements of trees and soil moisture determinations down to 86 cm indicate that all the mature trees are rooted mainly below 86 cm. At least one large tree is apparently rooted down to 6 m. A planting of Q. agrifolia acorns that were buried to simulate squirrel caches survived to establish many more seedlings than surface planted acorns due mainly to protection from predation and drying and to conditions affording good radicle penetration. In an open planting cattle destroyed all the seedlings that were established while most of the seedlings remained in a planting closed to cattle. The complete lack of oak reproduction in open habitats and the restriction of reproduction for both species to rock outcrops since 1910 is attributable to cattle grazing, which has been continuous since about 1910. The last reproduction of Q. engelmannii in the GOW's without outcrops and the peak reproduction of Q. agrifolia in the DOW occurred between 1890 and 1910. This may be explained partly by the fact that for at least 10 years during this time livestock were excluded due to a dry land farming operation in the area. More than half of the living Q. engelmannii were established before any known influence of European men and their livestock (1820) and there has been a general decline in establishment since then. This might be expected since they usually occur in open and exposed habitats which would be most subject to grazing pressure. There was a simultaneous establishment and rapid buildup of the Q. agrifolia population around rock outcrops in the DOW with the entrance of European man and his livestock which may be due to ground squirrels depositing acorns around their burrows which are often associated with rock outcrops. These squirrels are known to come into new areas after disturbance by man. Also about this time filaree, a new preferred food source for squirrels (in addition to acorns), was being established on California range lands which probably resulted in an increase in the squirrel population. An effective squirrel poisoning program was begun in the 1920's and this may also account for the decreased establishment of Q. agrifolia since this time even around rock outcrops. Title: Some factors controlling the establishment and distribution of Quercus agrifolia Nee and Q. engelmannii Greene in certain southern California oak woodlands Author: Snow, Gerald Eldon The structure of two oak woodland types in the Santa Rosa region of the Santa Ana Mountains of southern California has been described by Zuill (1967). One type called the grass oak woodland (GOW) is composed mainly of Q. engelmannii on hills and slopes. The other type called the dense oak woodland (DOW) is composed equally of Q. engelmannii and Q. agrifolia with twice the density of the GOW and is located in valleys with granite rock outcrops. An apparent lack of seedlings and saplings was noted in the area. The present study focuses on an explanation for the distribution patterns of the two oak species in the field and the factors which might be most important in influencing seedling establishment. Quercus agrifolia is restricted to cool moist protected locations on the north side and in fractures of rock outcrops because its acorns are sensitive to moisture loss on air drying, require constantly moist conditions for one to five weeks for water uptake to effect germination and have very rapid shoot development after germination. Seedlings may be intolerant of high temperatures in open grass litter, and seedlings and saplings appear less tolerant of fire than Q. engelmannii, which would also tend to restrict Q. agrifolia to protected locations around rock outcrops. The distribution of Q. engelmannii trees with respect to rock outcrops does not differ from a random distribution and the few that are associated with outcrops show a random distribution with respect to position around outcrops. The occurrence of Q. engelmannii in more open exposed habitats may be due to its acorns' tolerance to moisture loss on air drying, their ability to germinate with little or n6 additional water uptake, its self-planting mechanism and delayed shoot development, and the drought deciduous habit of seedlings and their tolerance to fire. In the laboratory the drought capable of killing 50% of the seedlings is about 100 bars soil moisture tension for Q. engelmannii and about 250 bars for Q. agrifolia. The survival of Q. agrifolia under a greater degree of soil drought is mainly attributable to its higher root: shoot ratio under these particular conditions. Seedlings of both species would be expected to survive any drought recorded in the field between 1968 and 1970 at their expected rooting depth. After a very wet rainy season none of the mature trees experienced any moisture stress by the end of the dry season even though the near surface soils were quite dry. After a quite dry year trees in the DOW showed significantly greater moisture stress than those on a hilltop in the GOW. The moisture stress measurements of trees and soil moisture determinations down to 86 cm indicate that all the mature trees are rooted mainly below 86 cm. At least one large tree is apparently rooted down to 6 m. A planting of Q. agrifolia acorns that were buried to simulate squirrel caches survived to establish many more seedlings than surface planted acorns due mainly to protection from predation and drying and to conditions affording good radicle penetration. In an open planting cattle destroyed all the seedlings that were established while most of the seedlings remained in a planting closed to cattle. The complete lack of oak reproduction in open habitats and the restriction of reproduction for both species to rock outcrops since 1910 is attributable to cattle grazing, which has been continuous since about 1910. The last reproduction of Q. engelmannii in the GOW's without outcrops and the peak reproduction of Q. agrifolia in the DOW occurred between 1890 and 1910. This may be explained partly by the fact that for at least 10 years during this time livestock were excluded due to a dry land farming operation in the area. More than half of the living Q. engelmannii were established before any known influence of European men and their livestock (1820) and there has been a general decline in establishment since then. This might be expected since they usually occur in open and exposed habitats which would be most subject to grazing pressure. There was a simultaneous establishment and rapid buildup of the Q. agrifolia population around rock outcrops in the DOW with the entrance of European man and his livestock which may be due to ground squirrels depositing acorns around their burrows which are often associated with rock outcrops. These squirrels are known to come into new areas after disturbance by man. Also about this time filaree, a new preferred food source for squirrels (in addition to acorns), was being established on California range lands which probably resulted in an increase in the squirrel population. An effective squirrel poisoning program was begun in the 1920's and this may also account for the decreased establishment of Q. agrifolia since this time even around rock outcrops. Close

• 13. [Article] Stand Structures of Oregon White Oak Woodlands, Regeneration, and Their Relationships to the Environment in Southwestern Oregon

  This is the publisher’s final pdf. The published article is copyrighted by Northwest Scientific Association and can be found at: http://www.northwestscience.org/.

  Citation × Citation Citation Abstract Copy Title: Stand Structures of Oregon White Oak Woodlands, Regeneration, and Their Relationships to the Environment in Southwestern Oregon Author: Gilligan, Laurie A., Muir, Patricia S. This is the publisher’s final pdf. The published article is copyrighted by Northwest Scientific Association and can be found at: http://www.northwestscience.org/. Title: Stand Structures of Oregon White Oak Woodlands, Regeneration, and Their Relationships to the Environment in Southwestern Oregon Author: Gilligan, Laurie A., Muir, Patricia S. This is the publisher’s final pdf. The published article is copyrighted by Northwest Scientific Association and can be found at: http://www.northwestscience.org/. Close

• 14. [Article] Bird Abundance and Microhabitat Associations with Oak Mistletoe in Willamette Valley Oak Woodlands

  In the last 200 years there have been significant declines in the amount and structural complexity of oak-dominated forests and savannahs in the Pacific Northwest. Restoring oak systems often involves ...

  Citation × Citation Citation Abstract Copy Title: Bird Abundance and Microhabitat Associations with Oak Mistletoe in Willamette Valley Oak Woodlands Author: Pritchard, Kyle R. In the last 200 years there have been significant declines in the amount and structural complexity of oak-dominated forests and savannahs in the Pacific Northwest. Restoring oak systems often involves selectively thinning stands of oaks in order to reduce competition for sunlight. In choosing which trees to cut, land managers often remove trees with obvious signs of disease or infection. One such infection is the parasitic mistletoe Phoradendron villosum, commonly referred to as Oak Mistletoe. However, the consequences of removing mistletoe-laden trees from the woodlands for oak-associated wildlife have not been studied. Mistletoe species play an important role in ecosystems globally, by providing habitat resources for wildlife, but the role of Oak Mistletoe in an oak-dominated ecosystem is almost completely undocumented. In order to investigate relationships between Oak Mistletoe and bird abundance and diversity, I quantified breeding bird use of Oregon White Oaks (Quercus garryana) with mistletoe loads between zero and 112 plants per tree, at five study sites in the Willamette Valley in the spring of 2014. In addition, I quantified six microhabitat features related to mistletoe infection, including branch swellings, dead wood, loose/missing bark, natural cavities, excavated cavities, deep cracks in the bole, and bole coverage by Poison Oak (Toxicodendron diversilobum). My results suggest that 1) structural heterogeneity within the crown of the tree and 2) bird abundance, species richness, and use of trees are positively associated with mistletoe load. In order to investigate the use of Oak Mistletoe fruits as a wildlife food resource, I recruited citizen scientists to record observations of birds feeding on mistletoe fruits in the fall of 2014 and winter of 2015 in western Oregon. In addition, I installed six camera traps in Oregon White Oak trees in order to capture additional observations of birds and other wildlife feeding on Oak Mistletoe fruits. My results suggest that Oak Mistletoe is a fall and winter food resource for Western Bluebirds (Sialia mexicana), American Robins (Turdus migratorius), Cedar Waxwings (Bombycilla cedrorum), Wild Turkeys (Meleagris gallopavo), and Western Grey Squirrels (Sciurus griseus). In this study, Western Bluebirds were observed to feed on mistletoe fruits up to 14 times more frequently than other bird species. By retaining some trees with mistletoe in the crown, land managers may be able to maintain the habitat quality for some wildlife species that use the microhabitat features and fruit resources associated with mistletoe. Title: Bird Abundance and Microhabitat Associations with Oak Mistletoe in Willamette Valley Oak Woodlands Author: Pritchard, Kyle R. In the last 200 years there have been significant declines in the amount and structural complexity of oak-dominated forests and savannahs in the Pacific Northwest. Restoring oak systems often involves selectively thinning stands of oaks in order to reduce competition for sunlight. In choosing which trees to cut, land managers often remove trees with obvious signs of disease or infection. One such infection is the parasitic mistletoe Phoradendron villosum, commonly referred to as Oak Mistletoe. However, the consequences of removing mistletoe-laden trees from the woodlands for oak-associated wildlife have not been studied. Mistletoe species play an important role in ecosystems globally, by providing habitat resources for wildlife, but the role of Oak Mistletoe in an oak-dominated ecosystem is almost completely undocumented. In order to investigate relationships between Oak Mistletoe and bird abundance and diversity, I quantified breeding bird use of Oregon White Oaks (Quercus garryana) with mistletoe loads between zero and 112 plants per tree, at five study sites in the Willamette Valley in the spring of 2014. In addition, I quantified six microhabitat features related to mistletoe infection, including branch swellings, dead wood, loose/missing bark, natural cavities, excavated cavities, deep cracks in the bole, and bole coverage by Poison Oak (Toxicodendron diversilobum). My results suggest that 1) structural heterogeneity within the crown of the tree and 2) bird abundance, species richness, and use of trees are positively associated with mistletoe load. In order to investigate the use of Oak Mistletoe fruits as a wildlife food resource, I recruited citizen scientists to record observations of birds feeding on mistletoe fruits in the fall of 2014 and winter of 2015 in western Oregon. In addition, I installed six camera traps in Oregon White Oak trees in order to capture additional observations of birds and other wildlife feeding on Oak Mistletoe fruits. My results suggest that Oak Mistletoe is a fall and winter food resource for Western Bluebirds (Sialia mexicana), American Robins (Turdus migratorius), Cedar Waxwings (Bombycilla cedrorum), Wild Turkeys (Meleagris gallopavo), and Western Grey Squirrels (Sciurus griseus). In this study, Western Bluebirds were observed to feed on mistletoe fruits up to 14 times more frequently than other bird species. By retaining some trees with mistletoe in the crown, land managers may be able to maintain the habitat quality for some wildlife species that use the microhabitat features and fruit resources associated with mistletoe. Close

• 15. [Article] Monitoring the effects of oak woodland restoration on birds in the Willamette Valley, Oregon

  Pathways Internship Program

  Citation × Citation Citation Abstract Copy Title: Monitoring the effects of oak woodland restoration on birds in the Willamette Valley, Oregon Author: Martinez, Elena Pathways Internship Program Title: Monitoring the effects of oak woodland restoration on birds in the Willamette Valley, Oregon Author: Martinez, Elena Pathways Internship Program Close

• 16. [Article] Vegetation and climate of the northwest coast of North America during the last 500 K.Y. : high–resolution pollen evidence from the northern California margin

  Pollen analyses of sediments from Holes 1019C, 1019E, 1020C, and 1020D as well as piston Core EW9504-17 provide continuous, chronostratigraphically controlled proxy vegetation and climate data for coastal ...

  Citation × Citation Citation Abstract Copy Title: Vegetation and climate of the northwest coast of North America during the last 500 K.Y. : high–resolution pollen evidence from the northern California margin Author: Lyle, Mitchell, Heusser, Linda, Mix, Alan C. Pollen analyses of sediments from Holes 1019C, 1019E, 1020C, and 1020D as well as piston Core EW9504-17 provide continuous, chronostratigraphically controlled proxy vegetation and climate data for coastal northwest North America for the last ~500 k.y. Systematic changes in the representation of the diagnostic components of northern California plant assemblages clearly show orbital-scale variations. Interglacials are all marked by an abrupt increase in alder followed by expansion of lowland oak woodland and redwood forests. Glacials are dominated by montane forest and woodland assemblages. This sequence reflects large-scale climatic controls (e.g., orbital-scale variation in insolation and Northern Hemisphere ice sheets) in western North America over the last five glacial cycles. Regional climatic control (variations in sea-surface conditions) is implied by the differential development of xeric oak and mesic redwood communities. Title: Vegetation and climate of the northwest coast of North America during the last 500 K.Y. : high–resolution pollen evidence from the northern California margin Author: Lyle, Mitchell, Heusser, Linda, Mix, Alan C. Pollen analyses of sediments from Holes 1019C, 1019E, 1020C, and 1020D as well as piston Core EW9504-17 provide continuous, chronostratigraphically controlled proxy vegetation and climate data for coastal northwest North America for the last ~500 k.y. Systematic changes in the representation of the diagnostic components of northern California plant assemblages clearly show orbital-scale variations. Interglacials are all marked by an abrupt increase in alder followed by expansion of lowland oak woodland and redwood forests. Glacials are dominated by montane forest and woodland assemblages. This sequence reflects large-scale climatic controls (e.g., orbital-scale variation in insolation and Northern Hemisphere ice sheets) in western North America over the last five glacial cycles. Regional climatic control (variations in sea-surface conditions) is implied by the differential development of xeric oak and mesic redwood communities. Close

• 17. [Article] Granary-Site Selection by Acorn Woodpeckers in the Willamette Valley,

  © 2006 by the Northwest Scientific Association

  Citation × Citation Citation Abstract Copy Title: Granary-Site Selection by Acorn Woodpeckers in the Willamette Valley, Author: Rosenberg, Daniel K., Johnson, Eric M. © 2006 by the Northwest Scientific Association Title: Granary-Site Selection by Acorn Woodpeckers in the Willamette Valley, Author: Rosenberg, Daniel K., Johnson, Eric M. © 2006 by the Northwest Scientific Association Close

• 18. [Article] Movements, habitat associations, and survival of Columbian white-tailed deer in western Oregon

  Columbian white-tailed deer (Odocoileus virginianus leucurus, CWTD) are a geographically isolated and federally endangered sub-species for which there is a paucity of recent ecological information. I described ...

  Citation × Citation Citation Abstract Copy Title: Movements, habitat associations, and survival of Columbian white-tailed deer in western Oregon Author: Ricca, Mark A. Columbian white-tailed deer (Odocoileus virginianus leucurus, CWTD) are a geographically isolated and federally endangered sub-species for which there is a paucity of recent ecological information. I described and examined sources of variation in spatial use patterns (i.e. home range, areas of concentrated use, and movements), habitat associations, and survival for adult and fawn CWTD in Douglas County, Oregon. I radio-collared and monitored 64 adult CWTD and 36 newborn fawn CWTD from ca. December 1995 - September 1998. Locations for adults were obtained from September 1996 - December 1998. Locations for fawns were obtained from June - September, 1997 - 1998. Spatial use estimates for adults tended to be variable among deer. Mean 95% fixed kernel home range size was 74.5 ha (CV = 83%), while areas of concentrated use averaged 8.5 ha (CV = 93%). The sexes appeared to be partitioning space because males had larger home ranges, areas of concentrated use (which are analogous to core areas), and movements than females. Deer inhabiting human-influenced areas (suburban deer) consistently exhibited smaller movements and used less space than those away from human influence (wild deer). Mean home range size, area of concentrated use size, and distance between successive locations was generally greatest in fall and lowest in winter. Site fidelity to seasonal home ranges and areas of concentrated use was lowest between fall-winter and summer-fall. Unexpectedly, size of home ranges and areas of concentrated use were positively correlated with cover type heterogeneity. Annual adult survival rates averaged 0.73. Neither annual survival rates nor functions differed by sex or type. Survival over the entire 3 year study was low (0.39). Most deer died in winter from a combination of emaciation and disease and generally were in poor body condition. Oak-hardwood woodland, riparian, and oak-hardwood savanna shrub were the most frequently used cover types. On an annual basis, the majority of deer (31%) selected riparian areas. The frequency of selection of all non-riparian cover types was < 13%, as most deer either exhibited avoidance or 'neutral selection-avoidance' of these cover types. The probability of use for a particular patch was positively associated with proximity to a stream for 56% of all deer. However, the relative amount of edge within a particular patch had little effect on the odds of use. Patterns of use and selection tended to be similar between the sexes, but suburban deer used conifer and yard cover types more frequently than wild deer. Use and selection of cover types by deer did not significantly differ among seasons. CWTD also demonstrated higher use for more open cover types during crepuscular and nocturnal periods. Areas of concentrated use were random with respect to cover type composition, but were significantly associated with proximity ([less than or equal to] 200 m) to streams. Home ranges, areas of concentrated use, and movements of fawns were variable but tended to reflect their sedentary nature. Home range and area of concentrated use size were not correlated with percent coverage of oak-hardwood woodland, riparian, or shrub dominated cover types. Habitat use patterns were characterized by frequent use of oak-hardwood woodland and riparian cover types, and areas within 200 m of streams. These habitat use patterns may represent some degree of rigidity in habitat composition within fawning areas. However, there was no apparent selection of cover types or distance to stream classes within areas of concentrated use. Fawn survival to 6 months was low (0.15, 95% CI = 0.009 - 0.308) and was most similar to estimates from previous CWTD studies and unhunted white-tailed deer populations. Mortality was highest during approximately the first 1 - 1.5 months of life. There were no differences in survival to 6 months by sex, but females had significantly higher survival during the neonatal period than males. Survival time was unrelated to both movements and use of oak-hardwood woodland and riparian cover types. Predation was the most frequent (n = 8) cause of death, followed by abandonment (n = 5). Overall, adult CWTD were sedentary, dispersal movements were not readily apparent, and survival rates were within the range of rates reported for other white-tailed deer populations. Adult CWTD also exhibited a degree of specialization for riparian areas, and generalized use patterns for other cover types. CWTD fawns tended to use small areas, exhibited frequent use of oak-hardwood woodlands and areas near streams. Survival rates of adults and fawns may be suggestive of density dependent population responses. Title: Movements, habitat associations, and survival of Columbian white-tailed deer in western Oregon Author: Ricca, Mark A. Columbian white-tailed deer (Odocoileus virginianus leucurus, CWTD) are a geographically isolated and federally endangered sub-species for which there is a paucity of recent ecological information. I described and examined sources of variation in spatial use patterns (i.e. home range, areas of concentrated use, and movements), habitat associations, and survival for adult and fawn CWTD in Douglas County, Oregon. I radio-collared and monitored 64 adult CWTD and 36 newborn fawn CWTD from ca. December 1995 - September 1998. Locations for adults were obtained from September 1996 - December 1998. Locations for fawns were obtained from June - September, 1997 - 1998. Spatial use estimates for adults tended to be variable among deer. Mean 95% fixed kernel home range size was 74.5 ha (CV = 83%), while areas of concentrated use averaged 8.5 ha (CV = 93%). The sexes appeared to be partitioning space because males had larger home ranges, areas of concentrated use (which are analogous to core areas), and movements than females. Deer inhabiting human-influenced areas (suburban deer) consistently exhibited smaller movements and used less space than those away from human influence (wild deer). Mean home range size, area of concentrated use size, and distance between successive locations was generally greatest in fall and lowest in winter. Site fidelity to seasonal home ranges and areas of concentrated use was lowest between fall-winter and summer-fall. Unexpectedly, size of home ranges and areas of concentrated use were positively correlated with cover type heterogeneity. Annual adult survival rates averaged 0.73. Neither annual survival rates nor functions differed by sex or type. Survival over the entire 3 year study was low (0.39). Most deer died in winter from a combination of emaciation and disease and generally were in poor body condition. Oak-hardwood woodland, riparian, and oak-hardwood savanna shrub were the most frequently used cover types. On an annual basis, the majority of deer (31%) selected riparian areas. The frequency of selection of all non-riparian cover types was < 13%, as most deer either exhibited avoidance or 'neutral selection-avoidance' of these cover types. The probability of use for a particular patch was positively associated with proximity to a stream for 56% of all deer. However, the relative amount of edge within a particular patch had little effect on the odds of use. Patterns of use and selection tended to be similar between the sexes, but suburban deer used conifer and yard cover types more frequently than wild deer. Use and selection of cover types by deer did not significantly differ among seasons. CWTD also demonstrated higher use for more open cover types during crepuscular and nocturnal periods. Areas of concentrated use were random with respect to cover type composition, but were significantly associated with proximity ([less than or equal to] 200 m) to streams. Home ranges, areas of concentrated use, and movements of fawns were variable but tended to reflect their sedentary nature. Home range and area of concentrated use size were not correlated with percent coverage of oak-hardwood woodland, riparian, or shrub dominated cover types. Habitat use patterns were characterized by frequent use of oak-hardwood woodland and riparian cover types, and areas within 200 m of streams. These habitat use patterns may represent some degree of rigidity in habitat composition within fawning areas. However, there was no apparent selection of cover types or distance to stream classes within areas of concentrated use. Fawn survival to 6 months was low (0.15, 95% CI = 0.009 - 0.308) and was most similar to estimates from previous CWTD studies and unhunted white-tailed deer populations. Mortality was highest during approximately the first 1 - 1.5 months of life. There were no differences in survival to 6 months by sex, but females had significantly higher survival during the neonatal period than males. Survival time was unrelated to both movements and use of oak-hardwood woodland and riparian cover types. Predation was the most frequent (n = 8) cause of death, followed by abandonment (n = 5). Overall, adult CWTD were sedentary, dispersal movements were not readily apparent, and survival rates were within the range of rates reported for other white-tailed deer populations. Adult CWTD also exhibited a degree of specialization for riparian areas, and generalized use patterns for other cover types. CWTD fawns tended to use small areas, exhibited frequent use of oak-hardwood woodlands and areas near streams. Survival rates of adults and fawns may be suggestive of density dependent population responses. Close

• 19. [Article] Private forests, public policy : oak conservation on family forests in Oregon’s Willamette Valley

  In the United States, many of the thorniest natural resource conflicts occur on private lands. This is especially true in the Willamette Valley of Western Oregon where the hallmark habitat type, Oregon ...

  Citation × Citation Citation Abstract Copy Title: Private forests, public policy : oak conservation on family forests in Oregon’s Willamette Valley Author: Fischer, Alexandra Paige In the United States, many of the thorniest natural resource conflicts occur on private lands. This is especially true in the Willamette Valley of Western Oregon where the hallmark habitat type, Oregon white oak woodland and savanna, is imperiled. Almost exclusively found on private land, Oregon white oak is threatened by urban development, vineyards, tree plantations, and the elimination of the periodic fires to which it is adapted. While regional and local planners, conservationists and natural resource agencies are attempting to conserve oak, little effort has been made to understand the social group in whose hands the fate of much of the resource rests: family forest owners. This paper presents a case study of oak conservation on family forestlands in Oregon. Through individual and group interviews and building upon social constructionism and interpretive policy analysis, this research investigates how two stakeholder groups—family forest owners and natural resource professionals—frame the problem of oak’s decline and opportunities and constraints for its conservation. It also analyzes some of the conservation policies that informants suggested for oak. By illuminating owners’ needs, capacities and constraints, and identifying areas of common ground and conflict in informants’ interpretive frames, this research identifies ways to reach out to a target group with empathy, facilitate cooperation between stakeholders, and avert potential conflicts that arise from conservation strategies. Title: Private forests, public policy : oak conservation on family forests in Oregon’s Willamette Valley Author: Fischer, Alexandra Paige In the United States, many of the thorniest natural resource conflicts occur on private lands. This is especially true in the Willamette Valley of Western Oregon where the hallmark habitat type, Oregon white oak woodland and savanna, is imperiled. Almost exclusively found on private land, Oregon white oak is threatened by urban development, vineyards, tree plantations, and the elimination of the periodic fires to which it is adapted. While regional and local planners, conservationists and natural resource agencies are attempting to conserve oak, little effort has been made to understand the social group in whose hands the fate of much of the resource rests: family forest owners. This paper presents a case study of oak conservation on family forestlands in Oregon. Through individual and group interviews and building upon social constructionism and interpretive policy analysis, this research investigates how two stakeholder groups—family forest owners and natural resource professionals—frame the problem of oak’s decline and opportunities and constraints for its conservation. It also analyzes some of the conservation policies that informants suggested for oak. By illuminating owners’ needs, capacities and constraints, and identifying areas of common ground and conflict in informants’ interpretive frames, this research identifies ways to reach out to a target group with empathy, facilitate cooperation between stakeholders, and avert potential conflicts that arise from conservation strategies. Close

• 20. [Article] Granary-site selection by acorn woodpeckers in Benton County, Oregon

  The acorn woodpecker (Melanerpes formicivorus) is among the most common primary cavity nesters of the Oregon white oak (Quercus garryana) woodlands. Understanding their selection of granary sites is important ...

  Citation × Citation Citation Abstract Copy Title: Granary-site selection by acorn woodpeckers in Benton County, Oregon Author: Johnson, Eric M. The acorn woodpecker (Melanerpes formicivorus) is among the most common primary cavity nesters of the Oregon white oak (Quercus garryana) woodlands. Understanding their selection of granary sites is important in evaluating habitat quality and management actions. I hypothesized that granary locations would be consistent with the optimal foraging theory. Site characters were selected that were hypothesized to affect granary profitability. I compared site characteristics of granaries and non-granaries within the home ranges of 20 colonies in Benton County, Oregon during the winter of 2001. Granaries had greater oak basal area (x*=104 ± 16 dm2), shorter brush height (x*=-26 ± 7 cm), larger diameter at breast height (dbh) (x*=l1 ± 4 cm). Of 14 a priori models considered, I determined that the Forage Model was the best predictor of granary presence. This model is based solely on the oak basal area variable, a measure of potential acorn production. Increased acorn production in the vicinity of granaries is likely beneficial to the birds because minimal effort is expended in caching maximum forage. Title: Granary-site selection by acorn woodpeckers in Benton County, Oregon Author: Johnson, Eric M. The acorn woodpecker (Melanerpes formicivorus) is among the most common primary cavity nesters of the Oregon white oak (Quercus garryana) woodlands. Understanding their selection of granary sites is important in evaluating habitat quality and management actions. I hypothesized that granary locations would be consistent with the optimal foraging theory. Site characters were selected that were hypothesized to affect granary profitability. I compared site characteristics of granaries and non-granaries within the home ranges of 20 colonies in Benton County, Oregon during the winter of 2001. Granaries had greater oak basal area (x*=104 ± 16 dm2), shorter brush height (x*=-26 ± 7 cm), larger diameter at breast height (dbh) (x*=l1 ± 4 cm). Of 14 a priori models considered, I determined that the Forage Model was the best predictor of granary presence. This model is based solely on the oak basal area variable, a measure of potential acorn production. Increased acorn production in the vicinity of granaries is likely beneficial to the birds because minimal effort is expended in caching maximum forage. Close