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• 341. [Article] Sugar application and nitrogen pools in Wyoming big sagebrush communities and exotic annual grasslands

  Within A rtemisia tridentata ssp. wyomingensis Nutt. (Wyoming big sagebrush) communities of the Great Basin, lands dominated by the exotic annual grass Bromus tectorum L. (cheatgrass) are increasing at ...

  Citation × Citation Citation Abstract Copy Title: Sugar application and nitrogen pools in Wyoming big sagebrush communities and exotic annual grasslands Author: Witwicki, Dana L. Within A rtemisia tridentata ssp. wyomingensis Nutt. (Wyoming big sagebrush) communities of the Great Basin, lands dominated by the exotic annual grass Bromus tectorum L. (cheatgrass) are increasing at an alarming rate. Carbon applications, which reduce plant-available soil N, have been suggested as a way to give native vegetation a competitive advantage over exotic annual grasses when reseeding after a fire. The main objectives of my study were to 1) compare N pools in intact A. tridentata- and B. tectorum-dominated communities to look for evidence of ecosystem changes associated with annual grass invasion, and 2) quantify and compare the effects of sugar and nitrogen additions on N pools in each of these communities. Research occurred at six sites in eastern Oregon and southwestern Idaho, each containing pairs of A. tridentata and exotic annual grass communities in close proximity. Pairs were carefully selected with similar soil types, precipitation, elevation, aspect, slope and ecological sites (i.e. potential vegetation and production). At the beginning of the cheatgrass growing season (late fall), three treatments (sugar, nitrogen or control) were applied. For soil pools, only one difference between untreated plots of annual and native communities was detected. In autumn. NO3 in the native community was about two-thirds the level in the annual community. The sugar treatment decreased inorganic N to near undetectable levels one week after application, and levels remained low six months later (during peak B. tectorum biomass). Although the sugar treatment did not increase microbial biomass N from chloroform fumigation extraction, we found higher '5N in microbial biomass and soil organic matter, suggesting that more N remained in the microbial pooi over the growing season. The reduction of aboveground plant biomass by sugar and the increase of aboveground plant biomass from nitrogen addition were more pronounced for B. tectorum than for native plants. Plant responses indicated that treatment with labile carbon like sugar may be useful tools for restoration of native plants and for prevention of B. tectorum dominance, but additional research is necessary to quantify dose responses of B. tectorum to sugar. Title: Sugar application and nitrogen pools in Wyoming big sagebrush communities and exotic annual grasslands Author: Witwicki, Dana L. Within A rtemisia tridentata ssp. wyomingensis Nutt. (Wyoming big sagebrush) communities of the Great Basin, lands dominated by the exotic annual grass Bromus tectorum L. (cheatgrass) are increasing at an alarming rate. Carbon applications, which reduce plant-available soil N, have been suggested as a way to give native vegetation a competitive advantage over exotic annual grasses when reseeding after a fire. The main objectives of my study were to 1) compare N pools in intact A. tridentata- and B. tectorum-dominated communities to look for evidence of ecosystem changes associated with annual grass invasion, and 2) quantify and compare the effects of sugar and nitrogen additions on N pools in each of these communities. Research occurred at six sites in eastern Oregon and southwestern Idaho, each containing pairs of A. tridentata and exotic annual grass communities in close proximity. Pairs were carefully selected with similar soil types, precipitation, elevation, aspect, slope and ecological sites (i.e. potential vegetation and production). At the beginning of the cheatgrass growing season (late fall), three treatments (sugar, nitrogen or control) were applied. For soil pools, only one difference between untreated plots of annual and native communities was detected. In autumn. NO3 in the native community was about two-thirds the level in the annual community. The sugar treatment decreased inorganic N to near undetectable levels one week after application, and levels remained low six months later (during peak B. tectorum biomass). Although the sugar treatment did not increase microbial biomass N from chloroform fumigation extraction, we found higher '5N in microbial biomass and soil organic matter, suggesting that more N remained in the microbial pooi over the growing season. The reduction of aboveground plant biomass by sugar and the increase of aboveground plant biomass from nitrogen addition were more pronounced for B. tectorum than for native plants. Plant responses indicated that treatment with labile carbon like sugar may be useful tools for restoration of native plants and for prevention of B. tectorum dominance, but additional research is necessary to quantify dose responses of B. tectorum to sugar. Close

• 342. [Article] Creating Useful and Useable Climate Tools for Sagebrush Land Management Through Scientist and Manager Collaboration

  The sagebrush ecosystem, home to numerous plant and animal species including big sagebrush (Artemisia tridentata) and the endemic greater sage-grouse (Centrocercus urophasianus), has endured fragmentation ...

  Citation × Citation Citation Abstract Copy Title: Creating Useful and Useable Climate Tools for Sagebrush Land Management Through Scientist and Manager Collaboration Author: Brown, Melanie The sagebrush ecosystem, home to numerous plant and animal species including big sagebrush (Artemisia tridentata) and the endemic greater sage-grouse (Centrocercus urophasianus), has endured fragmentation and degradation of both quantity and quality due to the cumulative and synergistic relationships between an abundance of individual disturbances including grazing, invasive annuals and fire. Climate change may now be an additional threat that poses the greatest risk to these imperiled habitats. Natural resource agencies such as the Bureau of Land Management (BLM) seek to conserve sagelands through land management activities that ensure the survival of sage-grouse and continuity of the sagebrush biome. Web-based climate tools can help convey climate information that may be necessary for long-term land management, but these tools may not agree with the needs of land managers, may be too complex, or may be misinterpreted. To overcome barriers of user compatibility, the participation of both climate scientists and land managers is necessary during tool development. With the collaboration of Oregon and Idaho BLM sagebrush land managers and climate scientists, this study sought to assess land manager needs and define the criteria for useful and useable climate tools. Using an initial online survey, individual phone interviews with land managers, and a follow-up online survey, a series of land management activities and related climate variables were identified, and several web-based climate tools were assessed. Most managers perform vegetation management through a variety of means including seeding and herbicide application. Such activities are affected by the magnitude and timing of precipitation and temperature, as well as other variables, on seasonal and annual timeframes. For planning purposes land managers also need information on long-term 10-20 year climate trends. The act of listening to the needs of land managers uncovered communication barriers, and provided feedback on existing climate tools emphasizing accessibility, dependability and consistency, clear explanation of terminology, effective visualizations, and relevant spatial and temporal scales to the scope of management activities. We also identified a need for basic information and education on the location of existing climate tools and climate impacts, and a need for near-term forecasting tools that could bridge the gap between weather (≤ 6 months) and climate (≥ 30 years) projections. Keywords: sagebrush, sage-grouse, Oregon State University, climate change, BLM, Oregon, Idaho, Great Basin, land management, collaboration, climate tools Title: Creating Useful and Useable Climate Tools for Sagebrush Land Management Through Scientist and Manager Collaboration Author: Brown, Melanie The sagebrush ecosystem, home to numerous plant and animal species including big sagebrush (Artemisia tridentata) and the endemic greater sage-grouse (Centrocercus urophasianus), has endured fragmentation and degradation of both quantity and quality due to the cumulative and synergistic relationships between an abundance of individual disturbances including grazing, invasive annuals and fire. Climate change may now be an additional threat that poses the greatest risk to these imperiled habitats. Natural resource agencies such as the Bureau of Land Management (BLM) seek to conserve sagelands through land management activities that ensure the survival of sage-grouse and continuity of the sagebrush biome. Web-based climate tools can help convey climate information that may be necessary for long-term land management, but these tools may not agree with the needs of land managers, may be too complex, or may be misinterpreted. To overcome barriers of user compatibility, the participation of both climate scientists and land managers is necessary during tool development. With the collaboration of Oregon and Idaho BLM sagebrush land managers and climate scientists, this study sought to assess land manager needs and define the criteria for useful and useable climate tools. Using an initial online survey, individual phone interviews with land managers, and a follow-up online survey, a series of land management activities and related climate variables were identified, and several web-based climate tools were assessed. Most managers perform vegetation management through a variety of means including seeding and herbicide application. Such activities are affected by the magnitude and timing of precipitation and temperature, as well as other variables, on seasonal and annual timeframes. For planning purposes land managers also need information on long-term 10-20 year climate trends. The act of listening to the needs of land managers uncovered communication barriers, and provided feedback on existing climate tools emphasizing accessibility, dependability and consistency, clear explanation of terminology, effective visualizations, and relevant spatial and temporal scales to the scope of management activities. We also identified a need for basic information and education on the location of existing climate tools and climate impacts, and a need for near-term forecasting tools that could bridge the gap between weather (≤ 6 months) and climate (≥ 30 years) projections. Keywords: sagebrush, sage-grouse, Oregon State University, climate change, BLM, Oregon, Idaho, Great Basin, land management, collaboration, climate tools Close

• 343. [Article] Spatial and ecological analysis of red fir decline in California using FIA data

  Red fir (Abies magnifica) is a high elevation conifer generally growing between an altitude of 1,400 and 2,700 meters. In California, red fir grows in the Sierra Nevada, the Klamath Mountains, the eastern ...

  Citation × Citation Citation Abstract Copy Title: Spatial and ecological analysis of red fir decline in California using FIA data Author: Mortenson, Leif A. Red fir (Abies magnifica) is a high elevation conifer generally growing between an altitude of 1,400 and 2,700 meters. In California, red fir grows in the Sierra Nevada, the Klamath Mountains, the eastern edges of the northern Californian Coast Ranges, and in the southern Cascades. Red fir commonly grows in pure stands and is often found in association with white fir (Abies concolor), lodgepole pine (Pinus contorta) or Jeffrey pine (Pinus Jeffreyi). Red fir is present in popular recreational areas including Yosemite, Kings Canyon, Sequoia and Lassen Volcanic national parks as well as the Mt. Shasta area and the Lake Tahoe region. Increasing and higher-than-expected red fir mortality and decline over the past five years has been observed in the central Sierra Nevada. This mortality and decline is seen as being caused by a complex interaction of biotic, anthropogenic and abiotic factors. The abiotic factors include drought, climate change (especially decreased snowpack), and the effects of changing fire regimes. The key anthropogenic factors are air pollution and forest management. The biotic factors include red fir dwarf mistletoe (Arceuthobium abietinum f. sp. magnificae), Annosus root disease (Heterobasidion annosum), Cytospora canker (Cytospora abietis), and the fir engraver beetle (Scolytus ventralis). Using USFS Forest Inventory & Analysis (FIA) plots at a density of one every 5.47 km (3.4 miles) across California allowed for the first stand-level analysis of the entire red fir distribution zone in California. The results show that mortality is increasing in red fir, which suggests that at least a short term decline is occurring. The rate at which mortality is increasing varies, depending on which analysis approach is used and decreases if recently burned plots are removed from the analysis. At the individual tree level, red fir mortality (all size classes) is occurring at an annual rate of 2.64%. Red fir dwarf mistletoe is the most significant factor in red fir mortality and decline based on our field observations and statistical analysis. There is a clear visual and statistical difference in forest health between areas that possess red fir dwarf mistletoe and those that don't. This remains true even when stands are heavily stocked and Annosus root disease is present, suggesting that Annosus root disease (which is common throughout the red fir distribution range) is greatly exacerbated by the presence of red fir dwarf mistletoe. Cytospora canker is associated with red fir dwarf mistletoe, and is likely a significant reason why the red fir dwarf mistletoe impacts red fir forest health so significantly. The only variation in spatial pattern of red fir mortality in California is an area of very low red fir mortality around Mt. Shasta (where red fir dwarf mistletoes does not occur). There was not a consistent correlation between red fir mortality and drought stress. The amount of fir engraver activity in California is not well characterized making it difficult to assess its' role in red fir mortality. Title: Spatial and ecological analysis of red fir decline in California using FIA data Author: Mortenson, Leif A. Red fir (Abies magnifica) is a high elevation conifer generally growing between an altitude of 1,400 and 2,700 meters. In California, red fir grows in the Sierra Nevada, the Klamath Mountains, the eastern edges of the northern Californian Coast Ranges, and in the southern Cascades. Red fir commonly grows in pure stands and is often found in association with white fir (Abies concolor), lodgepole pine (Pinus contorta) or Jeffrey pine (Pinus Jeffreyi). Red fir is present in popular recreational areas including Yosemite, Kings Canyon, Sequoia and Lassen Volcanic national parks as well as the Mt. Shasta area and the Lake Tahoe region. Increasing and higher-than-expected red fir mortality and decline over the past five years has been observed in the central Sierra Nevada. This mortality and decline is seen as being caused by a complex interaction of biotic, anthropogenic and abiotic factors. The abiotic factors include drought, climate change (especially decreased snowpack), and the effects of changing fire regimes. The key anthropogenic factors are air pollution and forest management. The biotic factors include red fir dwarf mistletoe (Arceuthobium abietinum f. sp. magnificae), Annosus root disease (Heterobasidion annosum), Cytospora canker (Cytospora abietis), and the fir engraver beetle (Scolytus ventralis). Using USFS Forest Inventory & Analysis (FIA) plots at a density of one every 5.47 km (3.4 miles) across California allowed for the first stand-level analysis of the entire red fir distribution zone in California. The results show that mortality is increasing in red fir, which suggests that at least a short term decline is occurring. The rate at which mortality is increasing varies, depending on which analysis approach is used and decreases if recently burned plots are removed from the analysis. At the individual tree level, red fir mortality (all size classes) is occurring at an annual rate of 2.64%. Red fir dwarf mistletoe is the most significant factor in red fir mortality and decline based on our field observations and statistical analysis. There is a clear visual and statistical difference in forest health between areas that possess red fir dwarf mistletoe and those that don't. This remains true even when stands are heavily stocked and Annosus root disease is present, suggesting that Annosus root disease (which is common throughout the red fir distribution range) is greatly exacerbated by the presence of red fir dwarf mistletoe. Cytospora canker is associated with red fir dwarf mistletoe, and is likely a significant reason why the red fir dwarf mistletoe impacts red fir forest health so significantly. The only variation in spatial pattern of red fir mortality in California is an area of very low red fir mortality around Mt. Shasta (where red fir dwarf mistletoes does not occur). There was not a consistent correlation between red fir mortality and drought stress. The amount of fir engraver activity in California is not well characterized making it difficult to assess its' role in red fir mortality. Close

• 344. [Article] Impacts of fuel reduction thinning treatments on oak and chaparral communities of southwestern Oregon

  In response to concerns about excessive stand densities and high-severity wildfires, land managers in the western United States are carrying out extensive programs of fuel reduction thinning. How will ...

  Citation × Citation Citation Abstract Copy Title: Impacts of fuel reduction thinning treatments on oak and chaparral communities of southwestern Oregon Author: Perchemlides, Keith A. In response to concerns about excessive stand densities and high-severity wildfires, land managers in the western United States are carrying out extensive programs of fuel reduction thinning. How will these sudden reductions in canopy cover and associated changes in habitat affect native and exotic herbaceous vegetation and canopy species regeneration? Where thinning treatments have both fuel-reduction and ecological restoration objectives, to what extent are these goals compatible? I compared vegetation and abiotic site characteristics between thinned and unthinned chaparral and oak communities of southwestern Oregon where landscape-scale fuel-reduction thinning is occurring. I sampled paired thinned and unthinned transects, established four to seven years post-treatment. I also contrasted impacts of manual vs. mechanical thinning methods, and examined differences in herbaceous composition and responses among canopy community types. Thinning treatments had significant impacts on site conditions and herbaceous cover and composition. Herbaceous cover increased on thinned sites, but species richness and diversity did not change. The strongest differences were decreases in perennial species cover and a near doubling of cover by annual species on thinned sites. While overall proportions of natives and exotics did not change, there were changes at the functional group level. Exotic annual grass cover and the proportion of herbaceous community cover composed of these species increased, while cover by native perennial grasses and regeneration of oaks did not. Cover and proportion of native annual forbs increased more than all other functional groups, while exotic annual forbs and native perennial forbs declined. Herbaceous communities at thinned sites had an early-post-disturbance type of composition dominated by native annual forbs and exotic annual grasses four to seven years after treatments. Re-establishment of native shrubs was sparse in thinned areas, likely due to a lack of fire-stimulated germination. Sites that varied in canopy species composition also supported different herbaceous communities in the absence of thinning, and appeared to respond differently to fuel reduction treatments. Manual and mechanical treatment impacts on abiotic site conditions differed, but their overall impacts on vegetation across canopy community types did not. Treatment type differences in herbaceous responses to thinning were found within some canopy vegetation groups, but sample sizes were small. Results suggest that fuel-reduction thinning may have some unintended negative impacts on oak and chaparral communities of southwestern Oregon. Although treatments have altered fuel conditions, thinning does not appear to have achieved restoration goals and may have substantially changed the composition and regeneration of native perennial communities including canopy species. Continued research and expanded monitoring that account for differences between canopy vegetation communities and treatment types are needed to inform adaptive management in these ecosystems. Title: Impacts of fuel reduction thinning treatments on oak and chaparral communities of southwestern Oregon Author: Perchemlides, Keith A. In response to concerns about excessive stand densities and high-severity wildfires, land managers in the western United States are carrying out extensive programs of fuel reduction thinning. How will these sudden reductions in canopy cover and associated changes in habitat affect native and exotic herbaceous vegetation and canopy species regeneration? Where thinning treatments have both fuel-reduction and ecological restoration objectives, to what extent are these goals compatible? I compared vegetation and abiotic site characteristics between thinned and unthinned chaparral and oak communities of southwestern Oregon where landscape-scale fuel-reduction thinning is occurring. I sampled paired thinned and unthinned transects, established four to seven years post-treatment. I also contrasted impacts of manual vs. mechanical thinning methods, and examined differences in herbaceous composition and responses among canopy community types. Thinning treatments had significant impacts on site conditions and herbaceous cover and composition. Herbaceous cover increased on thinned sites, but species richness and diversity did not change. The strongest differences were decreases in perennial species cover and a near doubling of cover by annual species on thinned sites. While overall proportions of natives and exotics did not change, there were changes at the functional group level. Exotic annual grass cover and the proportion of herbaceous community cover composed of these species increased, while cover by native perennial grasses and regeneration of oaks did not. Cover and proportion of native annual forbs increased more than all other functional groups, while exotic annual forbs and native perennial forbs declined. Herbaceous communities at thinned sites had an early-post-disturbance type of composition dominated by native annual forbs and exotic annual grasses four to seven years after treatments. Re-establishment of native shrubs was sparse in thinned areas, likely due to a lack of fire-stimulated germination. Sites that varied in canopy species composition also supported different herbaceous communities in the absence of thinning, and appeared to respond differently to fuel reduction treatments. Manual and mechanical treatment impacts on abiotic site conditions differed, but their overall impacts on vegetation across canopy community types did not. Treatment type differences in herbaceous responses to thinning were found within some canopy vegetation groups, but sample sizes were small. Results suggest that fuel-reduction thinning may have some unintended negative impacts on oak and chaparral communities of southwestern Oregon. Although treatments have altered fuel conditions, thinning does not appear to have achieved restoration goals and may have substantially changed the composition and regeneration of native perennial communities including canopy species. Continued research and expanded monitoring that account for differences between canopy vegetation communities and treatment types are needed to inform adaptive management in these ecosystems. Close

• 345. [Article] Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial

  Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the ...

  Citation × Citation Citation Abstract Copy Title: Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial Author: Bartels, Marilynn R. Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the few wetland prairies remaining after 150 years of agriculture and urbanization. Sidalcea nelsoniana, listed as threatened under the federal Endangered Species Act, is native to these wetland prairies. The studies described here provide basic information about the habitat requirements and tolerances of S. nelsoniana while testing for the first time the impact of specific management techniques on its growth and reproduction. The effects of prescribed burning and mowing on S. nelsoniana and its habitat were investigated in a field population at W.L. Finley National Wildlife Refuge near Corvallis, Oregon. Measurements of S. nelsoniana and aspects of the surrounding vegetation were recorded during the summer of 1998 within 112 permanent S. nelsoniana-centered quadrats. Burning and mowing treatments were applied in the fall of 1998 and the same measurements of S. nelsoniana and the surrounding vegetation were recorded during the summer of 1999. Treatments had no direct effects on S. nelsoniana performance, but burning and mowing reduced canopy cover, a primary goal of prairie maintenance and restoration. Because perennials often respond slowly to changes in habitat, effects of these manipulations may be more evident in future years. Wetland species may also be sensitive to site hydrology, so maintaining the proper water regime is another important component of wetland prairie management and restoration. A second experimental study evaluated the flooding tolerance of S. nelsoniana. Rhizome fragments were transplanted into pots exposed to four flooding conditions: drained soil, saturated soil with no standing water, standing water from mid-November through mid-April and standing water from mid-November through mid-June. Plants with drained soil died as the spring rains declined, and plants flooded past April died by mid-June. Plants in saturated soils and those flooded until mid-April were most successful. These two treatments most closely match conditions found in Willamette Valley wetland prairies, including S. nelsoniana sites, and suggest that the current distribution of S. nelsoniana approximately matches its hydrologic requirements. Management plans to flood a S. nelsoniana site beyond mid-April might harm this protected species. Title: Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial Author: Bartels, Marilynn R. Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the few wetland prairies remaining after 150 years of agriculture and urbanization. Sidalcea nelsoniana, listed as threatened under the federal Endangered Species Act, is native to these wetland prairies. The studies described here provide basic information about the habitat requirements and tolerances of S. nelsoniana while testing for the first time the impact of specific management techniques on its growth and reproduction. The effects of prescribed burning and mowing on S. nelsoniana and its habitat were investigated in a field population at W.L. Finley National Wildlife Refuge near Corvallis, Oregon. Measurements of S. nelsoniana and aspects of the surrounding vegetation were recorded during the summer of 1998 within 112 permanent S. nelsoniana-centered quadrats. Burning and mowing treatments were applied in the fall of 1998 and the same measurements of S. nelsoniana and the surrounding vegetation were recorded during the summer of 1999. Treatments had no direct effects on S. nelsoniana performance, but burning and mowing reduced canopy cover, a primary goal of prairie maintenance and restoration. Because perennials often respond slowly to changes in habitat, effects of these manipulations may be more evident in future years. Wetland species may also be sensitive to site hydrology, so maintaining the proper water regime is another important component of wetland prairie management and restoration. A second experimental study evaluated the flooding tolerance of S. nelsoniana. Rhizome fragments were transplanted into pots exposed to four flooding conditions: drained soil, saturated soil with no standing water, standing water from mid-November through mid-April and standing water from mid-November through mid-June. Plants with drained soil died as the spring rains declined, and plants flooded past April died by mid-June. Plants in saturated soils and those flooded until mid-April were most successful. These two treatments most closely match conditions found in Willamette Valley wetland prairies, including S. nelsoniana sites, and suggest that the current distribution of S. nelsoniana approximately matches its hydrologic requirements. Management plans to flood a S. nelsoniana site beyond mid-April might harm this protected species. Close

• 346. [Article] Increasing the abundance of rare native wetland prairie species

  Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species ...

  Citation × Citation Citation Abstract Copy Title: Increasing the abundance of rare native wetland prairie species Author: Goodridge, Jennifer, Wilson, Mark V., Clark, Deborah Louise, 1950- Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species are urgently needed, particularly those strategies that promote the regeneration of native species from seed. Fire may be an important factor in promoting regeneration of native species from seed because of its historical role in maintaining the prairie landscape. The study objectives were (1) to determine the effect of prescribed burning on regeneration of native species from seed, and (2) to establish predictive relationships between easily measured plant traits and seedling establishment rates in the field. The general approach was to sow seeds of target wetland prairie species during the fall into experimental field plots already established at the Danebo Wetland, Eugene, OR. Seedling establishment rates were then compared between burned and unburned plots the following spring. To establish predictive relationships these seedling establishment rates were related to selected seed and seedling traits measured under laboratory conditions. Overall seedling establishment rates showed no significant differences between burned (7.0%) and unburned plots (8.7%), although for the seven species showing positive responses to prescribed burning, the increase was approximately doubled in the burned plots. Burning significantly increased the seedling establishment rates of three species, Wyethia angustifolia, Grindelia integrifolia, and Danthonia californica. Seedling establishment significantly decreased with burning for one species, Sidalcea campestris. For three of the four endangered, threatened or rare species, Aster curtus, Horkelia congesta, and Sidalcea cusickii var. purpurea, seedling establishment rates were smaller in the burned plots compared to the unburned plots, although the differences were not significant. Lomatium bradshawii had no seedlings establish in either the burned or the unburned plots. Plant weight 7 days after germination was the best trait at predicting field seedling establishment rates for both the burned plots and the unburned plots, explaining a significant amount of variation in establishment rates: 70% for the burned plots and 45% for the unburned plots. This model could be used by managers to choose species for sowing in burned and unburned prairies or to estimate seeding rates at burned and unburned sites. Title: Increasing the abundance of rare native wetland prairie species Author: Goodridge, Jennifer, Wilson, Mark V., Clark, Deborah Louise, 1950- Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species are urgently needed, particularly those strategies that promote the regeneration of native species from seed. Fire may be an important factor in promoting regeneration of native species from seed because of its historical role in maintaining the prairie landscape. The study objectives were (1) to determine the effect of prescribed burning on regeneration of native species from seed, and (2) to establish predictive relationships between easily measured plant traits and seedling establishment rates in the field. The general approach was to sow seeds of target wetland prairie species during the fall into experimental field plots already established at the Danebo Wetland, Eugene, OR. Seedling establishment rates were then compared between burned and unburned plots the following spring. To establish predictive relationships these seedling establishment rates were related to selected seed and seedling traits measured under laboratory conditions. Overall seedling establishment rates showed no significant differences between burned (7.0%) and unburned plots (8.7%), although for the seven species showing positive responses to prescribed burning, the increase was approximately doubled in the burned plots. Burning significantly increased the seedling establishment rates of three species, Wyethia angustifolia, Grindelia integrifolia, and Danthonia californica. Seedling establishment significantly decreased with burning for one species, Sidalcea campestris. For three of the four endangered, threatened or rare species, Aster curtus, Horkelia congesta, and Sidalcea cusickii var. purpurea, seedling establishment rates were smaller in the burned plots compared to the unburned plots, although the differences were not significant. Lomatium bradshawii had no seedlings establish in either the burned or the unburned plots. Plant weight 7 days after germination was the best trait at predicting field seedling establishment rates for both the burned plots and the unburned plots, explaining a significant amount of variation in establishment rates: 70% for the burned plots and 45% for the unburned plots. This model could be used by managers to choose species for sowing in burned and unburned prairies or to estimate seeding rates at burned and unburned sites. Close

• 347. [Article] FACT SHEET: BLM, USFS Greater Sage-Grouse Conservation Effort

  Effective conservation of the greater sage-grouse and its habitat requires a collaborative, landscape-scale, science-based approach that includes strong federal plans, a strong commitment to conservation ...

  Citation × Citation Citation Abstract Copy Title: FACT SHEET: BLM, USFS Greater Sage-Grouse Conservation Effort Author: Bureau of Land Management, U.S. Forest Service Effective conservation of the greater sage-grouse and its habitat requires a collaborative, landscape-scale, science-based approach that includes strong federal plans, a strong commitment to conservation on state and private lands, and a proactive strategy to reduce the risk of rangeland fires. Since public lands make up roughly half of the remaining sage-grouse habitat, management decisions by the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS) are critical. The BLM and USFS land use plans will conserve key sagebrush habitat, address identified threats to the greater sage-grouse and promote sustainable economic development in the West. The plans were a key factor in the U.S. Fish and Wildlife Service (FWS) determination that the charismatic rangeland bird does not warrant protection under the Endangered Species Act (ESA). The plans will not only benefit the greater sage-grouse, but will also preserve the West’s heritage of ranching and outdoor recreation; protect hundreds of wildlife species such as elk, mule deer and golden eagles that also rely on sagebrush habitat; and promote balance between conservation and development. A healthy economy and a healthy ecosystem are inextricably linked. The sagebrush habitat supports a vibrant ranching economy, as well as over $1 billion in economic activity from outdoor recreation. The plans conserve the most important sage-grouse habitat while still providing access to key resources. For example, the vast majority of areas with high potential for oil, gas and renewable energy development are outside of sage-grouse habitat. Strong federal plans are one part of the equation. States, ranchers, sportsmen, energy developers and other partners are also implementing smart, effective conservation measures that will help ensure the health of iconic sagebrush landscapes for years to come. More than 1,100 ranchers and partners across the West are working with the Natural Resources Conservation Service’s (NRCS) Sage Grouse Initiative to restore more than 4.4 million acres of habitat while maintaining working landscapes. Additionally, the FWS and the BLM have also have commitments on 5.5 million acres in Candidate Conservation agreements on private and federal lands. Title: FACT SHEET: BLM, USFS Greater Sage-Grouse Conservation Effort Author: Bureau of Land Management, U.S. Forest Service Effective conservation of the greater sage-grouse and its habitat requires a collaborative, landscape-scale, science-based approach that includes strong federal plans, a strong commitment to conservation on state and private lands, and a proactive strategy to reduce the risk of rangeland fires. Since public lands make up roughly half of the remaining sage-grouse habitat, management decisions by the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS) are critical. The BLM and USFS land use plans will conserve key sagebrush habitat, address identified threats to the greater sage-grouse and promote sustainable economic development in the West. The plans were a key factor in the U.S. Fish and Wildlife Service (FWS) determination that the charismatic rangeland bird does not warrant protection under the Endangered Species Act (ESA). The plans will not only benefit the greater sage-grouse, but will also preserve the West’s heritage of ranching and outdoor recreation; protect hundreds of wildlife species such as elk, mule deer and golden eagles that also rely on sagebrush habitat; and promote balance between conservation and development. A healthy economy and a healthy ecosystem are inextricably linked. The sagebrush habitat supports a vibrant ranching economy, as well as over $1 billion in economic activity from outdoor recreation. The plans conserve the most important sage-grouse habitat while still providing access to key resources. For example, the vast majority of areas with high potential for oil, gas and renewable energy development are outside of sage-grouse habitat. Strong federal plans are one part of the equation. States, ranchers, sportsmen, energy developers and other partners are also implementing smart, effective conservation measures that will help ensure the health of iconic sagebrush landscapes for years to come. More than 1,100 ranchers and partners across the West are working with the Natural Resources Conservation Service’s (NRCS) Sage Grouse Initiative to restore more than 4.4 million acres of habitat while maintaining working landscapes. Additionally, the FWS and the BLM have also have commitments on 5.5 million acres in Candidate Conservation agreements on private and federal lands. Close

• 348. [Article] Otis Mountain/Moffet Table fuels management project environmental assessment

  102 pp. Tables, maps, references, appendices, illus. The Otis Mountain/Moffet Table Project Area encompasses approximately 22,547 acres of BLM-managed lands and 10,835 acres of privately owned lands within ...

  Citation × Citation Citation Abstract Copy Title: Otis Mountain/Moffet Table fuels management project environmental assessment Author: United States. Bureau of Land Management. Burns District Year: 2008, 2007 102 pp. Tables, maps, references, appendices, illus. The Otis Mountain/Moffet Table Project Area encompasses approximately 22,547 acres of BLM-managed lands and 10,835 acres of privately owned lands within portions of six grazing allotments north of Drewsey, Oregon. Grazing allotments included within the Project Area include: Birch Creek (T. 18 S., R. 35 E., Sections 20-21; 28; 33), Otis Mountain (T. 18 S., R. 35 E., Sections 22-27; T. 18 S., R. 36 E., Section 31; T. 19 S., R. 35 E., Sections 1-3; 10-15; T. 19 S., R. 36 E., Sections 6-7; 18), Moffet Table (T. 18 S., R. 34 E., Sections 23-26; 34-36; T. 18 S., R. 35 E., Sections 19-21; 28-33; T. 19 S., R. 34 E., Sections 1-3; 10-12; T. 19 S., R. 35 E., Sections 5-7; 17-18), Mule Creek (T. 18 S., R. 35 E., Sections 32-33; T. 19 S., R. 35 E., Sections 4-5; 8-9), Newell Field (T. 19 S., R. 35 E., Sections 14-15; 22-23; 26), and Big Upson Field (T. 19 S., R. 35 E., Sections 13; 24-25). Major road access to the project is provided by the Otis Valley Road along the eastern boundary of the Project Area and Forest Service Road 14 on the western boundary. Captured August 6, 2007. Title: Otis Mountain/Moffet Table fuels management project environmental assessment Author: United States. Bureau of Land Management. Burns District Year: 2008, 2007 102 pp. Tables, maps, references, appendices, illus. The Otis Mountain/Moffet Table Project Area encompasses approximately 22,547 acres of BLM-managed lands and 10,835 acres of privately owned lands within portions of six grazing allotments north of Drewsey, Oregon. Grazing allotments included within the Project Area include: Birch Creek (T. 18 S., R. 35 E., Sections 20-21; 28; 33), Otis Mountain (T. 18 S., R. 35 E., Sections 22-27; T. 18 S., R. 36 E., Section 31; T. 19 S., R. 35 E., Sections 1-3; 10-15; T. 19 S., R. 36 E., Sections 6-7; 18), Moffet Table (T. 18 S., R. 34 E., Sections 23-26; 34-36; T. 18 S., R. 35 E., Sections 19-21; 28-33; T. 19 S., R. 34 E., Sections 1-3; 10-12; T. 19 S., R. 35 E., Sections 5-7; 17-18), Mule Creek (T. 18 S., R. 35 E., Sections 32-33; T. 19 S., R. 35 E., Sections 4-5; 8-9), Newell Field (T. 19 S., R. 35 E., Sections 14-15; 22-23; 26), and Big Upson Field (T. 19 S., R. 35 E., Sections 13; 24-25). Major road access to the project is provided by the Otis Valley Road along the eastern boundary of the Project Area and Forest Service Road 14 on the western boundary. Captured August 6, 2007. Close

• 349. [Article] Seed and seedling ecology of Artemisia tridentata in a restoration context

  The semi-arid sagebrush steppe ecosystem is one of the largest biomes in North America. The steppe provides critical habitat and forage for wildlife and is economically important to recreation and livestock ...

  Citation × Citation Citation Abstract Copy Title: Seed and seedling ecology of Artemisia tridentata in a restoration context Author: Wijayratne, Upekala C. The semi-arid sagebrush steppe ecosystem is one of the largest biomes in North America. The steppe provides critical habitat and forage for wildlife and is economically important to recreation and livestock industries. However, the ecosystem is threatened primarily due to several negative effects associated with expansion of the exotic annual grass Bromus tectorum (cheatgrass). Because of these changes rehabilitation of the habitat is extremely difficult and energy intensive. Restoration of one of the foundation species, Artemisia tridentata (big sagebrush), is a function of seed availability, seed germination, seedling establishment and mature plant survival. Many studies have addressed various aspects of A. tridentata seed germination and mature plant ecophysiology, but gaps in our knowledge include seed bank dynamics and biotic interactions that may hinder seedling survival. The prevalence of large fires in B. tectorum-invaded habitat limits availability of dispersed seeds in the interior of burned areas, leaving pre-existing viable seeds in the soil seed bank as the primary natural seed source. I investigated seed longevity of two A. tridentata subspecies over a 2-year period by retrieving seed bags that were placed at varying depths and sampling soil and litter fractions of the existing seed bank across six locations in the Great Basin. Artemisia tridentata ssp. wyomingensis and A. t. ssp. vaseyana exhibited patterns of a steadily decreasing abundance of viable seeds on the surface and beneath litter, with 100% loss of surface seed viability in 24 months. However, 29-36% (A. t. ssp. wyomingensis) and 30-40% (A. t. ssp. vaseyana) of buried seeds remained viable throughout the duration of the experiment. Abundance of naturally occurring seeds varied considerably among locations and between years across the Great Basin for both subspecies. Loss of viable seeds from the existing seed bank between post-dispersal and pre-dispersal the following season was higher in magnitude for A. t. ssp. wyomingensis soil fractions compared to litter fractions, and higher overall than for A. t. ssp. vaseyana. Access to resources is critical during early spring when resources are plentiful, and this access affects the probability of survival through the summer drought period. Artemisia tridentata resource acquisition may be adversely affected during this time via root interaction mechanisms that are not mediated through resources (interference competition). I examined whether and how root interactions affected growth of A. t. ssp. wyomingensis by forcing its roots to interact with roots of conspecifics, B. tectorum, Elymus wawawaiensis (Snake River wheatgrass), and Agropyron xhybrid (cultivar 'Hycrest'). Activated carbon was used to counteract any potentially negative effects of root exudates. Artemisia tridentata above- and belowground biomass was not affected when grown with E. wawawaiensis or A. xhybrid compared to control seedlings, but root growth rate and branching density decreased when grown with B. tectorum (root growth: p < 0.01; branching density: p = 0.07). These effects did not occur in potting media amended with activated carbon but may have been the result of unintentional fertilization. Roots of A. tridentata seedlings changed direction or stopped growing altogether more often when grown into roots of conspecific seedlings than when contacting roots of other species (p = 0.08). The odds of this occurring decreased when seedlings were grown in activated carbon-amended potting medium. These results suggest that A. tridentata may have a chemical signaling mechanism to avoid roots of conspecifics. I also assessed whether root and shoot competition (resource-mediated or exploitative competition) of the three grass species affected A. t. ssp. wyomingensis seedling growth and survival, and whether root and shoot competition interacted to affect growth. Size-asymmetric competition takes place when a resource is preempted by a larger individual over a smaller individual, and the larger individual receives a disproportionately larger share of the resource for its relative size. Following wildfires, B. tectorum cover can increase significantly more than that of other species, potentially promoting asymmetric aboveground competition between it and A. tridentata seedlings. Root and shoot competition from B. tectorum lowered A. tridentata biomass dramatically compared to that of control seedlings, with shoot competition alone decreasing growth by over 80%. Only full competition from E. wawawaiensis tended to decrease A. tridentata growth compared to control seedlings, while A. xhybrid had no significant effect at all seedling growth. Bromus tectorum had an average of 92% cover and may explain why shoot competition from this species had such a substantial effect, whereas cover of E. wawawaiensis and A. xhybrid was 71% and 43%, respectively. Root and shoot competition did not interact for any of the grasses, indicating that there was no mechanism for positive or negative feedbacks between one form of competition and the other. Competition from shoots is likely not severe enough for asymmetric light competition to occur. The first study provides land managers with a bet-hedging application while the others offer insight into why the seedling life history stage, already vulnerable, has become more so with B. tectorum invasion. Reseeding techniques promoting burial of some A. tridentata seeds in the soil seed bank may increase restoration success by hedging against the potential for failure of establishment in the initial year of seeding. Selective thinning or removal of potential competitors may be required to benefit resource status of A. tridentata seedlings before the summer drought period commences. This is especially important in areas that are dominated by B. tectorum as competition from the annual reduces A. tridentata root growth substantially and may impact its ability to take up soil resources. Title: Seed and seedling ecology of Artemisia tridentata in a restoration context Author: Wijayratne, Upekala C. The semi-arid sagebrush steppe ecosystem is one of the largest biomes in North America. The steppe provides critical habitat and forage for wildlife and is economically important to recreation and livestock industries. However, the ecosystem is threatened primarily due to several negative effects associated with expansion of the exotic annual grass Bromus tectorum (cheatgrass). Because of these changes rehabilitation of the habitat is extremely difficult and energy intensive. Restoration of one of the foundation species, Artemisia tridentata (big sagebrush), is a function of seed availability, seed germination, seedling establishment and mature plant survival. Many studies have addressed various aspects of A. tridentata seed germination and mature plant ecophysiology, but gaps in our knowledge include seed bank dynamics and biotic interactions that may hinder seedling survival. The prevalence of large fires in B. tectorum-invaded habitat limits availability of dispersed seeds in the interior of burned areas, leaving pre-existing viable seeds in the soil seed bank as the primary natural seed source. I investigated seed longevity of two A. tridentata subspecies over a 2-year period by retrieving seed bags that were placed at varying depths and sampling soil and litter fractions of the existing seed bank across six locations in the Great Basin. Artemisia tridentata ssp. wyomingensis and A. t. ssp. vaseyana exhibited patterns of a steadily decreasing abundance of viable seeds on the surface and beneath litter, with 100% loss of surface seed viability in 24 months. However, 29-36% (A. t. ssp. wyomingensis) and 30-40% (A. t. ssp. vaseyana) of buried seeds remained viable throughout the duration of the experiment. Abundance of naturally occurring seeds varied considerably among locations and between years across the Great Basin for both subspecies. Loss of viable seeds from the existing seed bank between post-dispersal and pre-dispersal the following season was higher in magnitude for A. t. ssp. wyomingensis soil fractions compared to litter fractions, and higher overall than for A. t. ssp. vaseyana. Access to resources is critical during early spring when resources are plentiful, and this access affects the probability of survival through the summer drought period. Artemisia tridentata resource acquisition may be adversely affected during this time via root interaction mechanisms that are not mediated through resources (interference competition). I examined whether and how root interactions affected growth of A. t. ssp. wyomingensis by forcing its roots to interact with roots of conspecifics, B. tectorum, Elymus wawawaiensis (Snake River wheatgrass), and Agropyron xhybrid (cultivar 'Hycrest'). Activated carbon was used to counteract any potentially negative effects of root exudates. Artemisia tridentata above- and belowground biomass was not affected when grown with E. wawawaiensis or A. xhybrid compared to control seedlings, but root growth rate and branching density decreased when grown with B. tectorum (root growth: p < 0.01; branching density: p = 0.07). These effects did not occur in potting media amended with activated carbon but may have been the result of unintentional fertilization. Roots of A. tridentata seedlings changed direction or stopped growing altogether more often when grown into roots of conspecific seedlings than when contacting roots of other species (p = 0.08). The odds of this occurring decreased when seedlings were grown in activated carbon-amended potting medium. These results suggest that A. tridentata may have a chemical signaling mechanism to avoid roots of conspecifics. I also assessed whether root and shoot competition (resource-mediated or exploitative competition) of the three grass species affected A. t. ssp. wyomingensis seedling growth and survival, and whether root and shoot competition interacted to affect growth. Size-asymmetric competition takes place when a resource is preempted by a larger individual over a smaller individual, and the larger individual receives a disproportionately larger share of the resource for its relative size. Following wildfires, B. tectorum cover can increase significantly more than that of other species, potentially promoting asymmetric aboveground competition between it and A. tridentata seedlings. Root and shoot competition from B. tectorum lowered A. tridentata biomass dramatically compared to that of control seedlings, with shoot competition alone decreasing growth by over 80%. Only full competition from E. wawawaiensis tended to decrease A. tridentata growth compared to control seedlings, while A. xhybrid had no significant effect at all seedling growth. Bromus tectorum had an average of 92% cover and may explain why shoot competition from this species had such a substantial effect, whereas cover of E. wawawaiensis and A. xhybrid was 71% and 43%, respectively. Root and shoot competition did not interact for any of the grasses, indicating that there was no mechanism for positive or negative feedbacks between one form of competition and the other. Competition from shoots is likely not severe enough for asymmetric light competition to occur. The first study provides land managers with a bet-hedging application while the others offer insight into why the seedling life history stage, already vulnerable, has become more so with B. tectorum invasion. Reseeding techniques promoting burial of some A. tridentata seeds in the soil seed bank may increase restoration success by hedging against the potential for failure of establishment in the initial year of seeding. Selective thinning or removal of potential competitors may be required to benefit resource status of A. tridentata seedlings before the summer drought period commences. This is especially important in areas that are dominated by B. tectorum as competition from the annual reduces A. tridentata root growth substantially and may impact its ability to take up soil resources. Close

• 350. [Article] Vegetation and Small Mammal Responses to Western Juniper (Juniperus occidentalis) Control in Eastern Oregon

  Shrub-steppe ecosystems of western North America provide habitat for many wildlife species, are important components of public and private rangelands, and offer recreational opportunities for millions ...

  Citation × Citation Citation Abstract Copy Title: Vegetation and Small Mammal Responses to Western Juniper (Juniperus occidentalis) Control in Eastern Oregon Author: Morozumi, Corinne N. Shrub-steppe ecosystems of western North America provide habitat for many wildlife species, are important components of public and private rangelands, and offer recreational opportunities for millions of people. They are some of the most vulnerable ecosystems in the United States and have been altered by human activities such as livestock grazing, active fire suppression, conversion to agriculture, and urbanization of the west. Since the late 1800s woody encroachment of piñon-juniper species has also contributed to the loss of shrub-steppe habitat. Presently, land managers remove woody tree species in order to recover shrub-steppe although it is unclear how responses to these management activities differ due to site-specific conditions and existing woodland development. I studied post juniper-thinning responses in eastern Oregon at a wildlife area important as winter range for mule deer (Odocoileus hemionus). I investigated vegetative responses to western juniper (Juniperus occidentalis) thinning across a woodland development gradient and tested for interactive effects of juniper cutting and cattle exclusion. In addition, I explored plant and small mammal successional dynamics after juniper thinning and examined plant community responses within microhabitats created by the felled trees. I compared vegetative responses to juniper thinning as well as cattle exclusion among sites where juniper were subordinate (Phase I), co-dominant (Phase II), and dominant to shrubs and grasses (Phase III, sensu Miller et al. 2005). At the Phase I site, thinning did not increase herbaceous biomass while thinned plots at the Phase II site had 2.71 times more median herbaceous biomass (99.17% CI: 1.37 to 5.37 times more biomass) than unthinned plots. Conversely, herbaceous biomass at the Phase III juniper woodland site was 0.36 times lower in thinned plots when compared to unthinned plots (99.17% CI: 0.17 to 0.78 times less biomass). Unfortunately, many of the responses were driven by exotic species release. Where juniper were subordinate (Phase I), mean percent cover by exotic grass increased by 24.58 percentage points in thinned plots as compared to unthinned plots (98.30% CI: 0.27 to 48.90 percentage points higher). Thinning at the Phase II site increased mean exotic grass cover by an estimated 28.47 percentage points as compared to mean exotic cover in the same plots before treatment (98.30% CI: 4.15 to 52.79 percentage points higher cover). Median native bunchgrass cover at this site was 5.06 times greater after juniper treatment (99.7% CI: 1.78 to 14.35 times higher percent cover). I found few main or interactive effects of cattle exclosure after one year of treatment. Responses to grazing exclosure may take longer to develop. These results indicate that sites within the wildlife area respond differently to juniper management and that exotic grass control will be key to successful shrub-steppe recovery. In addition, I used a time-since-juniper thinning chronoseries consisting of plots cut in 2008, 2009, 2010, 2012, and an adjacent uncut control to explore how shrub-steppe flora and fauna are responding to juniper treatment through time. Shrub cover and seedling density were low in each plot. I recorded the highest seedling abundance (mean of 0.25 seedlings) in the uncut control plot. Median grass cover in the uncut control was 9.50% while in the most recently treated plot (2012) it was 26.75%. Small mammal relative abundance and diversity was low across all time-since-treatment plots though highest in the plot with the greatest time-since-treatment. Deer mouse (Peromyscus maniculatus) was the most abundant species in all plots and accounted for 70-95% of all unique captures. Least chipmunk (Tamias minimus) were present in the plot with greatest time-since-treatment indicating the potential recovery of key native shrubs since these small mammals perform an important seed dispersal role. I also investigated how potential microhabitats created by the felled juniper might support different plant communities. I assessed plant responses within zones created by 1) the felled tree (canopy zone), 2) the original duff zone, and 3) the between - tree interspace zone. The three zones had different plant community compositions as analyzed multivariately with non-metric multidimensional scaling (NMS). Canopy and duff zones were forb - dominated and had less exotic grass invasion while interspace zones were heavily invested with medusahead (Taeniatherum caput-medusae) and ventenata (Ventenata dubia). Exotic herbaceous productivity was lowest under the standing trees of the control plot and high in the interspace of all plots with juniper thinning. In the 2012 cut plot, grass cover was 27.90 percentage points less in the canopy zone compared to the interspace zone (98.75% CI: 17.64 to 38.16 percentage points less grass cover). In the uncut control, median native biomass was 2.08 times greater under the standing trees compared to the interspace (96.25% CI: 1.09 to 3.97 times more biomass). Results from the time-since-treatment chronoseries indicated that exotic grass dominance might be limiting shrub-steppe recovery. Active restoration of shrubs and native grasses may be necessary to address the dominance of exotic grass after juniper thinning. Positive signs of habitat recovery included small mammal responses though I was unable to calculate population estimates due to plot size. Title: Vegetation and Small Mammal Responses to Western Juniper (Juniperus occidentalis) Control in Eastern Oregon Author: Morozumi, Corinne N. Shrub-steppe ecosystems of western North America provide habitat for many wildlife species, are important components of public and private rangelands, and offer recreational opportunities for millions of people. They are some of the most vulnerable ecosystems in the United States and have been altered by human activities such as livestock grazing, active fire suppression, conversion to agriculture, and urbanization of the west. Since the late 1800s woody encroachment of piñon-juniper species has also contributed to the loss of shrub-steppe habitat. Presently, land managers remove woody tree species in order to recover shrub-steppe although it is unclear how responses to these management activities differ due to site-specific conditions and existing woodland development. I studied post juniper-thinning responses in eastern Oregon at a wildlife area important as winter range for mule deer (Odocoileus hemionus). I investigated vegetative responses to western juniper (Juniperus occidentalis) thinning across a woodland development gradient and tested for interactive effects of juniper cutting and cattle exclusion. In addition, I explored plant and small mammal successional dynamics after juniper thinning and examined plant community responses within microhabitats created by the felled trees. I compared vegetative responses to juniper thinning as well as cattle exclusion among sites where juniper were subordinate (Phase I), co-dominant (Phase II), and dominant to shrubs and grasses (Phase III, sensu Miller et al. 2005). At the Phase I site, thinning did not increase herbaceous biomass while thinned plots at the Phase II site had 2.71 times more median herbaceous biomass (99.17% CI: 1.37 to 5.37 times more biomass) than unthinned plots. Conversely, herbaceous biomass at the Phase III juniper woodland site was 0.36 times lower in thinned plots when compared to unthinned plots (99.17% CI: 0.17 to 0.78 times less biomass). Unfortunately, many of the responses were driven by exotic species release. Where juniper were subordinate (Phase I), mean percent cover by exotic grass increased by 24.58 percentage points in thinned plots as compared to unthinned plots (98.30% CI: 0.27 to 48.90 percentage points higher). Thinning at the Phase II site increased mean exotic grass cover by an estimated 28.47 percentage points as compared to mean exotic cover in the same plots before treatment (98.30% CI: 4.15 to 52.79 percentage points higher cover). Median native bunchgrass cover at this site was 5.06 times greater after juniper treatment (99.7% CI: 1.78 to 14.35 times higher percent cover). I found few main or interactive effects of cattle exclosure after one year of treatment. Responses to grazing exclosure may take longer to develop. These results indicate that sites within the wildlife area respond differently to juniper management and that exotic grass control will be key to successful shrub-steppe recovery. In addition, I used a time-since-juniper thinning chronoseries consisting of plots cut in 2008, 2009, 2010, 2012, and an adjacent uncut control to explore how shrub-steppe flora and fauna are responding to juniper treatment through time. Shrub cover and seedling density were low in each plot. I recorded the highest seedling abundance (mean of 0.25 seedlings) in the uncut control plot. Median grass cover in the uncut control was 9.50% while in the most recently treated plot (2012) it was 26.75%. Small mammal relative abundance and diversity was low across all time-since-treatment plots though highest in the plot with the greatest time-since-treatment. Deer mouse (Peromyscus maniculatus) was the most abundant species in all plots and accounted for 70-95% of all unique captures. Least chipmunk (Tamias minimus) were present in the plot with greatest time-since-treatment indicating the potential recovery of key native shrubs since these small mammals perform an important seed dispersal role. I also investigated how potential microhabitats created by the felled juniper might support different plant communities. I assessed plant responses within zones created by 1) the felled tree (canopy zone), 2) the original duff zone, and 3) the between - tree interspace zone. The three zones had different plant community compositions as analyzed multivariately with non-metric multidimensional scaling (NMS). Canopy and duff zones were forb - dominated and had less exotic grass invasion while interspace zones were heavily invested with medusahead (Taeniatherum caput-medusae) and ventenata (Ventenata dubia). Exotic herbaceous productivity was lowest under the standing trees of the control plot and high in the interspace of all plots with juniper thinning. In the 2012 cut plot, grass cover was 27.90 percentage points less in the canopy zone compared to the interspace zone (98.75% CI: 17.64 to 38.16 percentage points less grass cover). In the uncut control, median native biomass was 2.08 times greater under the standing trees compared to the interspace (96.25% CI: 1.09 to 3.97 times more biomass). Results from the time-since-treatment chronoseries indicated that exotic grass dominance might be limiting shrub-steppe recovery. Active restoration of shrubs and native grasses may be necessary to address the dominance of exotic grass after juniper thinning. Positive signs of habitat recovery included small mammal responses though I was unable to calculate population estimates due to plot size. Close