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• 11. [Article] Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities

  Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship ...

  Citation × Citation Citation Abstract Copy Title: Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities Author: Pool, Thomas K., Cucherousset, Julien, Boulêtreau, Stéphanie, Villéger, Sébastien, Strecker, Angela L., Grenouillet, Gaël Year: 2015 Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship remains limited. Community assembly theory predicts that niche partitioning will result in communities with a diverse array of functional traits, which in turn may facilitate a correspondingly diverse array of trophic interactions that define the trophic niche of those communities. The aim of our study is to test this prediction. Methods: We built a database composed of functional traits and stable isotope values (δ13C and δ15N) for 63 freshwater fish communities containing 109 species in 34 lentic and 29 lotic ecosystems. First, using linear mixed models (i.e. an alpha-diversity approach), we tested whether the taxonomic diversity of communities was positively associated with their functional diversity and if their functional diversity was positively associated with their trophic diversity. Second, we assessed the taxonomic, functional and trophic similarity of communities using multiple regression on distance matrices (MRM) and their respective ‘turnover’ and ‘nestedness-resultant’ components to test if the taxonomic similarity of communities was positively correlated with their functional similarity and if their functional similarity was positively associated with their trophic similarity (i.e. a beta-diversity approach). Results: We found that the functional diversity of communities increased as their taxonomic diversity increased. Similarly, the trophic diversity of communities increased as their functional diversity increased. The pairwise taxonomic and functional similarity of communities were also positively associated, but there was a weak relationship between the functional and trophic similarities of communities. Main conclusions: Our study demonstrates that communities with similar functional characteristics can have disparate food web structures, suggesting that additional site-specific factors influence community variation in trophic niche geometry. Determining the relative importance of functional characteristics and site-specific factors in shaping trophic interactions is crucial for a better understanding of how future species loss and species introductions will affect food web structure and ecosystem functioning. Title: Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities Author: Pool, Thomas K., Cucherousset, Julien, Boulêtreau, Stéphanie, Villéger, Sébastien, Strecker, Angela L., Grenouillet, Gaël Year: 2015 Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship remains limited. Community assembly theory predicts that niche partitioning will result in communities with a diverse array of functional traits, which in turn may facilitate a correspondingly diverse array of trophic interactions that define the trophic niche of those communities. The aim of our study is to test this prediction. Methods: We built a database composed of functional traits and stable isotope values (δ13C and δ15N) for 63 freshwater fish communities containing 109 species in 34 lentic and 29 lotic ecosystems. First, using linear mixed models (i.e. an alpha-diversity approach), we tested whether the taxonomic diversity of communities was positively associated with their functional diversity and if their functional diversity was positively associated with their trophic diversity. Second, we assessed the taxonomic, functional and trophic similarity of communities using multiple regression on distance matrices (MRM) and their respective ‘turnover’ and ‘nestedness-resultant’ components to test if the taxonomic similarity of communities was positively correlated with their functional similarity and if their functional similarity was positively associated with their trophic similarity (i.e. a beta-diversity approach). Results: We found that the functional diversity of communities increased as their taxonomic diversity increased. Similarly, the trophic diversity of communities increased as their functional diversity increased. The pairwise taxonomic and functional similarity of communities were also positively associated, but there was a weak relationship between the functional and trophic similarities of communities. Main conclusions: Our study demonstrates that communities with similar functional characteristics can have disparate food web structures, suggesting that additional site-specific factors influence community variation in trophic niche geometry. Determining the relative importance of functional characteristics and site-specific factors in shaping trophic interactions is crucial for a better understanding of how future species loss and species introductions will affect food web structure and ecosystem functioning. Close

• 12. [Article] FAGE determination of tropospheric HO and HO₂

  FAGE (fluorescence assay with gas expansion) was developed as a sensitive technique for the detection of low-concentration free radicals in the atmosphere. The application of FAGE to tropospheric hydroxyl ...

  Citation × Citation Citation Abstract Copy Title: FAGE determination of tropospheric HO and HO₂ Author: George, Linda Acha, Hard, Thomas M., O'Brien, Robert J. Year: 1995 FAGE (fluorescence assay with gas expansion) was developed as a sensitive technique for the detection of low-concentration free radicals in the atmosphere. The application of FAGE to tropospheric hydroxyl (H0) and hydroperoxyl (H0₂) radicals has yielded calibrated measurements of both species in both clean air and highly polluted urban air. For HO calibration, a continuously stirred tank reactor provides a uniform external HO concentration, which can be measured by gas chromatography of an HO-reactive hydrocarbon. The aerodynamics of the air-sampling process has been modeled computationally, with results that agree with empirical observations of the effects of nozzle diameter on HO loss during sampling. The authors have also modeled airborne fluid dynamics of a FAGE probe. They have recently obtained FAGE sensitivity as high as ± 1 × 10⁶ cm-³ for a 6-minute averaging period, during field studies in highly polluted Los Angeles air, yielding a 7:1 signal-to-noise ratio near midday. Multipass excitation can further improve this sensitivity. The authors summarize their recent field studies of HO and HO², current work on improved calibration methods, other improvements, and future plans. Title: FAGE determination of tropospheric HO and HO₂ Author: George, Linda Acha, Hard, Thomas M., O'Brien, Robert J. Year: 1995 FAGE (fluorescence assay with gas expansion) was developed as a sensitive technique for the detection of low-concentration free radicals in the atmosphere. The application of FAGE to tropospheric hydroxyl (H0) and hydroperoxyl (H0₂) radicals has yielded calibrated measurements of both species in both clean air and highly polluted urban air. For HO calibration, a continuously stirred tank reactor provides a uniform external HO concentration, which can be measured by gas chromatography of an HO-reactive hydrocarbon. The aerodynamics of the air-sampling process has been modeled computationally, with results that agree with empirical observations of the effects of nozzle diameter on HO loss during sampling. The authors have also modeled airborne fluid dynamics of a FAGE probe. They have recently obtained FAGE sensitivity as high as ± 1 × 10⁶ cm-³ for a 6-minute averaging period, during field studies in highly polluted Los Angeles air, yielding a 7:1 signal-to-noise ratio near midday. Multipass excitation can further improve this sensitivity. The authors summarize their recent field studies of HO and HO², current work on improved calibration methods, other improvements, and future plans. Close

• 13. [Article] Advancing Collaborative Solutions: Lessons from the Oregon Sage-Grouse Conservation Partnership (SageCon)

  The Sage-Grouse Conservation Partnership, also known as “SageCon,” was an unprecedented collaborative effort among federal, state, and private stakeholders to address landscape-scale threats to greater ...

  Citation × Citation Citation Abstract Copy Title: Advancing Collaborative Solutions: Lessons from the Oregon Sage-Grouse Conservation Partnership (SageCon) Author: Allen, Jennifer H., Odell, Turner, Babcock, Julia, Henrie, Charis Year: 2017 The Sage-Grouse Conservation Partnership, also known as “SageCon,” was an unprecedented collaborative effort among federal, state, and private stakeholders to address landscape-scale threats to greater sage-grouse while also acknowledging rural economic and community interests across eastern Oregon’s sagebrush range. A U.S. Fish and Wildlife Service (USFWS) preliminary finding that the sage-grouse warranted listing under the endangered species act, and a subsequent court settlement setting a deadline for a final listing decision were key drivers for SageCon participants to seek proactive solutions to protect the bird. A cadre of diverse Eastern Oregon stakeholders with experience working collaboratively on related public lands issues helped set the stage for the collaborative effort. As part of what the Department of the Interior described as a historic outcome, SageCon produced the 2015 Oregon Sage-Grouse Action Plan, which details voluntary and state-regulated conservation measures to preserve habitat and protect Oregon’s sage-grouse population from threats on public and private land. SageCon—as one part of a broader multi-state collaborative effort—led to a subsequent USFWS finding that the sage-grouse no longer warranted listing as endangered. In our study of this collaborative effort, we interviewed seventeen SageCon participants to identify collaborative approaches that may offer promise for other conservation and public policy efforts. We explored participant motivation for engaging in the process, collaborative process design, integration of science into the SageCon deliberations, and other experiences that interviewees found relevant. Title: Advancing Collaborative Solutions: Lessons from the Oregon Sage-Grouse Conservation Partnership (SageCon) Author: Allen, Jennifer H., Odell, Turner, Babcock, Julia, Henrie, Charis Year: 2017 The Sage-Grouse Conservation Partnership, also known as “SageCon,” was an unprecedented collaborative effort among federal, state, and private stakeholders to address landscape-scale threats to greater sage-grouse while also acknowledging rural economic and community interests across eastern Oregon’s sagebrush range. A U.S. Fish and Wildlife Service (USFWS) preliminary finding that the sage-grouse warranted listing under the endangered species act, and a subsequent court settlement setting a deadline for a final listing decision were key drivers for SageCon participants to seek proactive solutions to protect the bird. A cadre of diverse Eastern Oregon stakeholders with experience working collaboratively on related public lands issues helped set the stage for the collaborative effort. As part of what the Department of the Interior described as a historic outcome, SageCon produced the 2015 Oregon Sage-Grouse Action Plan, which details voluntary and state-regulated conservation measures to preserve habitat and protect Oregon’s sage-grouse population from threats on public and private land. SageCon—as one part of a broader multi-state collaborative effort—led to a subsequent USFWS finding that the sage-grouse no longer warranted listing as endangered. In our study of this collaborative effort, we interviewed seventeen SageCon participants to identify collaborative approaches that may offer promise for other conservation and public policy efforts. We explored participant motivation for engaging in the process, collaborative process design, integration of science into the SageCon deliberations, and other experiences that interviewees found relevant. Close

• 14. [Article] Studies of ecological factors that affect the population and distribution of the western gray squirrel in northcentral Oregon

  The western gray squirrel (Sciurus griseus griseus Ord) occur only in the Pacific states and in a small corner of extreme western Nevada. Field studies of aspects of the ecology of the most widely distributed ...

  Citation × Citation Citation Abstract Copy Title: Studies of ecological factors that affect the population and distribution of the western gray squirrel in northcentral Oregon Author: Foster, Susan Ann Year: 1992 The western gray squirrel (Sciurus griseus griseus Ord) occur only in the Pacific states and in a small corner of extreme western Nevada. Field studies of aspects of the ecology of the most widely distributed subspecies of western gray squirrel (S. griseus) were conducted at three sites in the ponderosa pine-Oregon white oak zone on the eastern slopes of Mt. Hood, Wasco County, Oregon, between 1981 and 1989. From 1981 through 1987, a Hunter Cooperation Program provided remains of squirrels shot during the annual late summer-early autumn hunting season. Other data were gathered through capture and release studies, radiotelemetry, and habitat analysis. The age structure of these populations, as revealed by examination of squirrels killed by hunters, is predominantly mature animals. Also, the population as estimated by hunter success during the Hunter Cooperation Program and by field observations appears to be declining. In the sites studied, western gray squirrels have two seasons of reproductive activity annually. Some individuals mate from January through March; their young emerge from the nest in May and June. Other individuals mate during May and June; their young emerge in August and September. The latter matings are usually the most productive. Analysis of nest trees and their surroundings revealed that nests are most likely to be located in mature trees that have well-developed crowns and occur in stands with a high degree of canopy closure. Nest trees were usually located within approximately 180 meters of permanent water and on sites with a south-southeasterly exposure. Home ranges of squirrels examined in this study were usually large compared to home ranges reported for this species elsewhere in its range. Given the cost of having large home ranges, it seems possible that the squirrels at these study sites exist in less than optimal ecological circumstances. Human factors that may have contributed to the decline of the populations in this study may include the nature of logging activities and the timing of the annual hunting season. Limiting factors other than human activities may include competition with other mast-consuming animals (mule deer, elk, wild turkeys, and three other species of squirrels) for limited and variable mast crops. Title: Studies of ecological factors that affect the population and distribution of the western gray squirrel in northcentral Oregon Author: Foster, Susan Ann Year: 1992 The western gray squirrel (Sciurus griseus griseus Ord) occur only in the Pacific states and in a small corner of extreme western Nevada. Field studies of aspects of the ecology of the most widely distributed subspecies of western gray squirrel (S. griseus) were conducted at three sites in the ponderosa pine-Oregon white oak zone on the eastern slopes of Mt. Hood, Wasco County, Oregon, between 1981 and 1989. From 1981 through 1987, a Hunter Cooperation Program provided remains of squirrels shot during the annual late summer-early autumn hunting season. Other data were gathered through capture and release studies, radiotelemetry, and habitat analysis. The age structure of these populations, as revealed by examination of squirrels killed by hunters, is predominantly mature animals. Also, the population as estimated by hunter success during the Hunter Cooperation Program and by field observations appears to be declining. In the sites studied, western gray squirrels have two seasons of reproductive activity annually. Some individuals mate from January through March; their young emerge from the nest in May and June. Other individuals mate during May and June; their young emerge in August and September. The latter matings are usually the most productive. Analysis of nest trees and their surroundings revealed that nests are most likely to be located in mature trees that have well-developed crowns and occur in stands with a high degree of canopy closure. Nest trees were usually located within approximately 180 meters of permanent water and on sites with a south-southeasterly exposure. Home ranges of squirrels examined in this study were usually large compared to home ranges reported for this species elsewhere in its range. Given the cost of having large home ranges, it seems possible that the squirrels at these study sites exist in less than optimal ecological circumstances. Human factors that may have contributed to the decline of the populations in this study may include the nature of logging activities and the timing of the annual hunting season. Limiting factors other than human activities may include competition with other mast-consuming animals (mule deer, elk, wild turkeys, and three other species of squirrels) for limited and variable mast crops. Close

• 15. [Article] Climate Change and Land Management Impact Rangeland Condition and Sage-Grouse Habitat in Southeastern Oregon

  Contemporary pressures on sagebrush steppe from climate change, exotic species, wildfire, and land use change threaten rangeland species such as the greater sage-grouse (Centrocercus urophasianus). To ...

  Citation × Citation Citation Abstract Copy Title: Climate Change and Land Management Impact Rangeland Condition and Sage-Grouse Habitat in Southeastern Oregon Author: Creutzburg, Megan K., Henderson, Emilie B., Conklin, David R. Year: 2015 Contemporary pressures on sagebrush steppe from climate change, exotic species, wildfire, and land use change threaten rangeland species such as the greater sage-grouse (Centrocercus urophasianus). To effectively manage sagebrush steppe landscapes for long-term goals, managers need information about the potential impacts of climate change, disturbances, and management activities. We integrated information from a dynamic global vegetation model, a sage-grouse habitat climate envelope model, and a state-and-transition simulation model to project broad-scale vegetation dynamics and potential sage-grouse habitat across 23.5 million acres in southeastern Oregon. We evaluated four climate scenarios, including continuing current climate and three scenarios of global climate change, and three management scenarios, including no management, current management and a sage-grouse habitat restoration scenario. All climate change scenarios projected expansion of moist shrub steppe and contraction of dry shrub steppe, but climate scenarios varied widely in the projected extent of xeric shrub steppe, where hot, dry summer conditions are unfavorable for sage-grouse. Wildfire increased by 26% over the century under current climate due to exotic grass encroachment, and by two- to four-fold across all climate change scenarios as extreme fire years became more frequent. Exotic grasses rapidly expanded in all scenarios as large areas of the landscape initially in semi-degraded condition converted to exotic-dominated systems. Due to the combination of exotic grass invasion, juniper encroachment, and climatic unsuitability for sage-grouse, projected sage-grouse habitat declined in the first several decades, but increased in area under the three climate change scenarios later in the century, as moist shrub steppe increased and rangeland condition improved. Management activities in the model were generally unsuccessful in controlling exotic grass invasion but were effective in slowing woodland expansion. Current levels of restoration treatments were insufficient to prevent some juniper expansion, but increased treatment rates under the restoration scenario maintained juniper near initial levels in priority treatment areas. Our simulations indicate that climate change may have both positive and negative implications for maintaining sage-grouse habitat. Title: Climate Change and Land Management Impact Rangeland Condition and Sage-Grouse Habitat in Southeastern Oregon Author: Creutzburg, Megan K., Henderson, Emilie B., Conklin, David R. Year: 2015 Contemporary pressures on sagebrush steppe from climate change, exotic species, wildfire, and land use change threaten rangeland species such as the greater sage-grouse (Centrocercus urophasianus). To effectively manage sagebrush steppe landscapes for long-term goals, managers need information about the potential impacts of climate change, disturbances, and management activities. We integrated information from a dynamic global vegetation model, a sage-grouse habitat climate envelope model, and a state-and-transition simulation model to project broad-scale vegetation dynamics and potential sage-grouse habitat across 23.5 million acres in southeastern Oregon. We evaluated four climate scenarios, including continuing current climate and three scenarios of global climate change, and three management scenarios, including no management, current management and a sage-grouse habitat restoration scenario. All climate change scenarios projected expansion of moist shrub steppe and contraction of dry shrub steppe, but climate scenarios varied widely in the projected extent of xeric shrub steppe, where hot, dry summer conditions are unfavorable for sage-grouse. Wildfire increased by 26% over the century under current climate due to exotic grass encroachment, and by two- to four-fold across all climate change scenarios as extreme fire years became more frequent. Exotic grasses rapidly expanded in all scenarios as large areas of the landscape initially in semi-degraded condition converted to exotic-dominated systems. Due to the combination of exotic grass invasion, juniper encroachment, and climatic unsuitability for sage-grouse, projected sage-grouse habitat declined in the first several decades, but increased in area under the three climate change scenarios later in the century, as moist shrub steppe increased and rangeland condition improved. Management activities in the model were generally unsuccessful in controlling exotic grass invasion but were effective in slowing woodland expansion. Current levels of restoration treatments were insufficient to prevent some juniper expansion, but increased treatment rates under the restoration scenario maintained juniper near initial levels in priority treatment areas. Our simulations indicate that climate change may have both positive and negative implications for maintaining sage-grouse habitat. Close

• 16. [Article] Quantifying Resilience of Multiple Ecosystem Services and Biodiversity in a Temperate Forest Landscape

  Resilience is increasingly being considered as a new paradigm of forest management among scientists, practitioners, and policymakers. However, metrics of resilience to environmental change are lacking. ...

  Citation × Citation Citation Abstract Copy Title: Quantifying Resilience of Multiple Ecosystem Services and Biodiversity in a Temperate Forest Landscape Author: Cantarello, Elena, Newton, Adrian C., Martin, Phillip A., Evans, Paul M., Gosal, Arjan, Lucash, Melissa S. Year: 2017 Resilience is increasingly being considered as a new paradigm of forest management among scientists, practitioners, and policymakers. However, metrics of resilience to environmental change are lacking. Faced with novel disturbances, forests may be able to sustain existing ecosystem services and biodiversity by exhibiting resilience, or alternatively these attributes may undergo either a linear or nonlinear decline. Here we provide a novel quantitative approach for assessing forest resilience that focuses on three components of resilience, namely resistance, recovery, and net change, using a spatially explicit model of forest dynamics. Under the pulse set scenarios, we explored the resilience of nine ecosystem services and four biodiversity measures following a one-off disturbance applied to an increasing percentage of forest area. Under the pulse + press set scenarios, the six disturbance intensities explored during the pulse set were followed by a continuous disturbance. We detected thresholds in net change under pulse + press scenarios for the majority of the ecosystem services and biodiversity measures, which started to decline sharply when disturbance affected >40% of the landscape. Thresholds in net change were not observed under the pulse scenarios, with the exception of timber volume and ground flora species richness. Thresholds were most pronounced for aboveground biomass, timber volume with respect to the ecosystem services, and ectomycorrhizal fungi and ground flora species richness with respect to the biodiversity measures. Synthesis and applications. The approach presented here illustrates how the multidimensionality of stability research in ecology can be addressed and how forest resilience can be estimated in practice. Managers should adopt specific management actions to support each of the three components of resilience separately, as these may respond differently to disturbance. In addition, management interventions aiming to deliver resilience should incorporate an assessment of both pulse and press disturbances to ensure detection of threshold responses to disturbance, so that appropriate management interventions can be identified. Title: Quantifying Resilience of Multiple Ecosystem Services and Biodiversity in a Temperate Forest Landscape Author: Cantarello, Elena, Newton, Adrian C., Martin, Phillip A., Evans, Paul M., Gosal, Arjan, Lucash, Melissa S. Year: 2017 Resilience is increasingly being considered as a new paradigm of forest management among scientists, practitioners, and policymakers. However, metrics of resilience to environmental change are lacking. Faced with novel disturbances, forests may be able to sustain existing ecosystem services and biodiversity by exhibiting resilience, or alternatively these attributes may undergo either a linear or nonlinear decline. Here we provide a novel quantitative approach for assessing forest resilience that focuses on three components of resilience, namely resistance, recovery, and net change, using a spatially explicit model of forest dynamics. Under the pulse set scenarios, we explored the resilience of nine ecosystem services and four biodiversity measures following a one-off disturbance applied to an increasing percentage of forest area. Under the pulse + press set scenarios, the six disturbance intensities explored during the pulse set were followed by a continuous disturbance. We detected thresholds in net change under pulse + press scenarios for the majority of the ecosystem services and biodiversity measures, which started to decline sharply when disturbance affected >40% of the landscape. Thresholds in net change were not observed under the pulse scenarios, with the exception of timber volume and ground flora species richness. Thresholds were most pronounced for aboveground biomass, timber volume with respect to the ecosystem services, and ectomycorrhizal fungi and ground flora species richness with respect to the biodiversity measures. Synthesis and applications. The approach presented here illustrates how the multidimensionality of stability research in ecology can be addressed and how forest resilience can be estimated in practice. Managers should adopt specific management actions to support each of the three components of resilience separately, as these may respond differently to disturbance. In addition, management interventions aiming to deliver resilience should incorporate an assessment of both pulse and press disturbances to ensure detection of threshold responses to disturbance, so that appropriate management interventions can be identified. Close