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• 41. [Article] Potential effects of climate change and fire management on fire behavior and vegetation patterns on an east Cascades landscape

  Climate exerts considerable control on wildfire regimes, and climate and wildfire are both major drivers of forest growth and succession in interior Northwest forests. Estimating potential response of ...

  Citation × Citation Citation Abstract Copy Title: Potential effects of climate change and fire management on fire behavior and vegetation patterns on an east Cascades landscape Author: Greaves, Heather E. Climate exerts considerable control on wildfire regimes, and climate and wildfire are both major drivers of forest growth and succession in interior Northwest forests. Estimating potential response of these landscapes to anticipated changes in climate helps researchers and land managers understand and mitigate impacts of climate change on important ecological and economic resources. Spatially explicit, mechanistic computer simulation models are powerful tools that permit researchers to incorporate climate and disturbance events along with vegetation physiology and phenology to explore complex potential effects of climate change over wide spatial and temporal scales. In this thesis, I used the simulation model FireBGCv2 to characterize potential response of fire, vegetation, and landscape dynamics to a range of possible future climate and fire management scenarios. The simulation landscape (~43,000 hectares) is part of Deschutes National Forest, which is located at the interface of maritime and continental climates and is known for its beauty and ecological diversity. Simulation scenarios included all combinations of +0°C, +3°C, and +6°C of warming; +10%, ±0%, and -10% historical precipitation; and 10% and 90% fire suppression, and were run for 500 years. To characterize fire dynamics, I investigated how mean fire frequency, intensity, and fuel loadings changed over time in all scenarios, and how fire and tree mortality interacted over time. To explore vegetation and landscape dynamics, I described the distribution and spatial arrangement of vegetation types and forest successional stages on the landscape, and used a nonmetric multidimensional scaling (NMS) ordination to holistically evaluate overall similarity of composition, structure, and landscape pattern among all simulation scenarios over time. Changes in precipitation had little effect on fire characteristics or vegetation and landscape characteristics, indicating that simulated precipitation changes were not sufficient to significantly affect vegetation moisture stress or fire behavior on this landscape. Current heavy fuel loads controlled early fire dynamics, with high mean fire intensities occurring early in all simulations. Increases in fire frequency accompanied all temperature increases, leading to decreasing fuel loads and fire intensities over time in warming scenarios. With no increase in temperature or in fire frequency, high fire intensities and heavier fuel loads were sustained. Over time, more fire associated with warming or less fire suppression increased the percentage of the landscape occupied by non-forest and fire-sensitive early seral forest successional stages, which tended to increase the percentage of fire area burning at high severity (in terms of tree mortality). This fire-vegetation relationship may reflect a return to a more historical range of conditions on this landscape. Higher temperatures and fire frequency led to significant spatial migration of forest types across the landscape, with communities at the highest and lowest elevations particularly affected. Warming led to an upslope shift of warm mixed conifer and ponderosa pine (Pinus ponderosa) forests, severely contracting (under 3° of warming) or eliminating (under 6° of warming) area dominated by mountain hemlock (Tsuga mertensiana) and cool, wet conifer forest in the high western portion of the landscape. In lower elevations, warming and fire together contributed to significant expansion of open (<10% tree canopy cover) forest and grass- and shrubland. The compositional changes and spatial shifts simulated in the warming scenarios suggest that climate change is likely to significantly affect forests on this landscape. Warming and associated fire also tended to increase heterogeneity of forest structural stages and landscape pattern, resulting in a more diverse distribution of structural stages, especially in lower elevations, and a more divided landscape of smaller forest stands. The NMS ordination emphasized the dissimilarity between the severe +6° scenarios and the other two temperature scenarios. The +0° and +3° scenarios differed from each other in composition (mainly because cool forest was lost in the +3° scenarios), but within a given level of fire suppression they remained remarkably similar in terms of overall composition, structure, and landscape pattern, while the +6° scenarios separated noticeably from them. Such decisive differences suggest that under the simulated ranges of precipitation and fire suppression, the interval between 3 and 6 degrees of warming on this landscape may capture an ecological threshold, or tipping point. Additional simulation research that incorporates (for example) management actions, insects and pathogens, and a wider array of precipitation scenarios could help illuminate more clearly the possible range of future landscape conditions. Still, these results provide a glimpse of potential divergent outcomes on this important landscape under possible future climates, and suggest that these forests will undergo considerable changes from both historical and current conditions in response to higher temperatures expected in this area. Some changes may be inevitable with warming, such as the upslope shift of warm forest types, but careful planning for fire and fuels management might allow land managers to modulate fire behavior and steer vegetation dynamics toward the most desirable outcome possible. Title: Potential effects of climate change and fire management on fire behavior and vegetation patterns on an east Cascades landscape Author: Greaves, Heather E. Climate exerts considerable control on wildfire regimes, and climate and wildfire are both major drivers of forest growth and succession in interior Northwest forests. Estimating potential response of these landscapes to anticipated changes in climate helps researchers and land managers understand and mitigate impacts of climate change on important ecological and economic resources. Spatially explicit, mechanistic computer simulation models are powerful tools that permit researchers to incorporate climate and disturbance events along with vegetation physiology and phenology to explore complex potential effects of climate change over wide spatial and temporal scales. In this thesis, I used the simulation model FireBGCv2 to characterize potential response of fire, vegetation, and landscape dynamics to a range of possible future climate and fire management scenarios. The simulation landscape (~43,000 hectares) is part of Deschutes National Forest, which is located at the interface of maritime and continental climates and is known for its beauty and ecological diversity. Simulation scenarios included all combinations of +0°C, +3°C, and +6°C of warming; +10%, ±0%, and -10% historical precipitation; and 10% and 90% fire suppression, and were run for 500 years. To characterize fire dynamics, I investigated how mean fire frequency, intensity, and fuel loadings changed over time in all scenarios, and how fire and tree mortality interacted over time. To explore vegetation and landscape dynamics, I described the distribution and spatial arrangement of vegetation types and forest successional stages on the landscape, and used a nonmetric multidimensional scaling (NMS) ordination to holistically evaluate overall similarity of composition, structure, and landscape pattern among all simulation scenarios over time. Changes in precipitation had little effect on fire characteristics or vegetation and landscape characteristics, indicating that simulated precipitation changes were not sufficient to significantly affect vegetation moisture stress or fire behavior on this landscape. Current heavy fuel loads controlled early fire dynamics, with high mean fire intensities occurring early in all simulations. Increases in fire frequency accompanied all temperature increases, leading to decreasing fuel loads and fire intensities over time in warming scenarios. With no increase in temperature or in fire frequency, high fire intensities and heavier fuel loads were sustained. Over time, more fire associated with warming or less fire suppression increased the percentage of the landscape occupied by non-forest and fire-sensitive early seral forest successional stages, which tended to increase the percentage of fire area burning at high severity (in terms of tree mortality). This fire-vegetation relationship may reflect a return to a more historical range of conditions on this landscape. Higher temperatures and fire frequency led to significant spatial migration of forest types across the landscape, with communities at the highest and lowest elevations particularly affected. Warming led to an upslope shift of warm mixed conifer and ponderosa pine (Pinus ponderosa) forests, severely contracting (under 3° of warming) or eliminating (under 6° of warming) area dominated by mountain hemlock (Tsuga mertensiana) and cool, wet conifer forest in the high western portion of the landscape. In lower elevations, warming and fire together contributed to significant expansion of open (<10% tree canopy cover) forest and grass- and shrubland. The compositional changes and spatial shifts simulated in the warming scenarios suggest that climate change is likely to significantly affect forests on this landscape. Warming and associated fire also tended to increase heterogeneity of forest structural stages and landscape pattern, resulting in a more diverse distribution of structural stages, especially in lower elevations, and a more divided landscape of smaller forest stands. The NMS ordination emphasized the dissimilarity between the severe +6° scenarios and the other two temperature scenarios. The +0° and +3° scenarios differed from each other in composition (mainly because cool forest was lost in the +3° scenarios), but within a given level of fire suppression they remained remarkably similar in terms of overall composition, structure, and landscape pattern, while the +6° scenarios separated noticeably from them. Such decisive differences suggest that under the simulated ranges of precipitation and fire suppression, the interval between 3 and 6 degrees of warming on this landscape may capture an ecological threshold, or tipping point. Additional simulation research that incorporates (for example) management actions, insects and pathogens, and a wider array of precipitation scenarios could help illuminate more clearly the possible range of future landscape conditions. Still, these results provide a glimpse of potential divergent outcomes on this important landscape under possible future climates, and suggest that these forests will undergo considerable changes from both historical and current conditions in response to higher temperatures expected in this area. Some changes may be inevitable with warming, such as the upslope shift of warm forest types, but careful planning for fire and fuels management might allow land managers to modulate fire behavior and steer vegetation dynamics toward the most desirable outcome possible. Close

• 42. [Article] The role of herbivores and productivity on community structure of rocky shores of the Galapagos Islands, Ecuador

  Ecosystems are facing increasing threats from human related activities, such as overfishing, pollution, habitat destruction, species invasions, and diseases, among others. While oceanic islands provide ...

  Citation × Citation Citation Abstract Copy Title: The role of herbivores and productivity on community structure of rocky shores of the Galapagos Islands, Ecuador Author: Vinueza, Luis R. Ecosystems are facing increasing threats from human related activities, such as overfishing, pollution, habitat destruction, species invasions, and diseases, among others. While oceanic islands provide natural laboratories to understand ecological and evolutionary process, they are also particularly vulnerable to these impacts, given their usual isolation from the mainland and the typically high endemism of their flora and fauna. However, we still lack a general understanding of how marine systems in the Galapagos Islands will be affected by multiple human impacts, more severe environmental perturbations and warmer oceans. Rocky shores have been a prime example for the advancement of ecological theories and for the creation of important concepts to support management decisions and conservation actions, such as the predation hypothesis, the keystone species concept and the development of environmental stress models. However, the majority of this knowledge comes from studies conducted at higher latitudes. While most attention in the tropics has been focused on coral reefs and mangroves, other habitats such as rocky shores have remained largely unexplored. The upwelling ecosystems of the Galapagos Archipelago constitute an ideal model where likely consequences of interactions between global climate change and human impacts (e.g. exploitation) can be studied. In particular, variation in ocean upwelling and downwelling conditions (Palacios 2004) associated with seasonal and interannual variability and large scale oceanic-atmospheric perturbations such as ENSO cycles with its warm El Niño (~cessation of upwelling conditions) and cold La Niña (~abnormal upwelling) phase (Chavez et al. 1999). Thus, the Galapagos situation offers a scenario whereby I can assess the interaction among nutrient supply, herbivory and abiotic fluctuations. I used this dynamic system to evaluate the influence of bottom up and top down effects on rocky shore communities. In Chapter 2 I evaluated the role of consumers at different levels of productivity. I manipulated four levels of herbivory, from no macro-herbivores to all herbivores present, combinations of all together, mostly fish, crabs, crabs and including marine iguanas, crabs, sea turtles and fish. I demonstrated that at sites of low productivity herbivores had consistent effects on community structure by reducing the abundance of erect macroalgae which decreased macroalgal and sessile invertebrate's species richness, diversity and evenness. In areas of mid and high productivity the role of consumers was affected by seasonal effects and by warm and cold phases of El Niño Southern Oscillation. In Chapter 3 I evaluated the interactive effect of consumers on species richness, diversity and evenness of primary producers and discussed the results in the context of prevailing top down views on the regulation of marine tropical communities. I further discuss the importance to manage both top down and bottom up factors to maintain ecosystem structure and function at tropical locations. In chapter 4 I used resource and consumer-stress models to predict the outcome of plant animal interactions. I observed how the impact of herbivory on primary producers was exacerbated by thermal stress and reduced algal biomass at times of low productivity and high temperature; this pattern shifted as productivity increased and thermal stress relaxed, which led to herbivores increasing, not decreasing algal biomass. Finally, chapter 5 provides the main conclusions about our work. I put our work in context of past and present ecological theories. I also offer a framework to manage this system, oriented to increasing the resistance and resilience of this fragile ecosystem. Title: The role of herbivores and productivity on community structure of rocky shores of the Galapagos Islands, Ecuador Author: Vinueza, Luis R. Ecosystems are facing increasing threats from human related activities, such as overfishing, pollution, habitat destruction, species invasions, and diseases, among others. While oceanic islands provide natural laboratories to understand ecological and evolutionary process, they are also particularly vulnerable to these impacts, given their usual isolation from the mainland and the typically high endemism of their flora and fauna. However, we still lack a general understanding of how marine systems in the Galapagos Islands will be affected by multiple human impacts, more severe environmental perturbations and warmer oceans. Rocky shores have been a prime example for the advancement of ecological theories and for the creation of important concepts to support management decisions and conservation actions, such as the predation hypothesis, the keystone species concept and the development of environmental stress models. However, the majority of this knowledge comes from studies conducted at higher latitudes. While most attention in the tropics has been focused on coral reefs and mangroves, other habitats such as rocky shores have remained largely unexplored. The upwelling ecosystems of the Galapagos Archipelago constitute an ideal model where likely consequences of interactions between global climate change and human impacts (e.g. exploitation) can be studied. In particular, variation in ocean upwelling and downwelling conditions (Palacios 2004) associated with seasonal and interannual variability and large scale oceanic-atmospheric perturbations such as ENSO cycles with its warm El Niño (~cessation of upwelling conditions) and cold La Niña (~abnormal upwelling) phase (Chavez et al. 1999). Thus, the Galapagos situation offers a scenario whereby I can assess the interaction among nutrient supply, herbivory and abiotic fluctuations. I used this dynamic system to evaluate the influence of bottom up and top down effects on rocky shore communities. In Chapter 2 I evaluated the role of consumers at different levels of productivity. I manipulated four levels of herbivory, from no macro-herbivores to all herbivores present, combinations of all together, mostly fish, crabs, crabs and including marine iguanas, crabs, sea turtles and fish. I demonstrated that at sites of low productivity herbivores had consistent effects on community structure by reducing the abundance of erect macroalgae which decreased macroalgal and sessile invertebrate's species richness, diversity and evenness. In areas of mid and high productivity the role of consumers was affected by seasonal effects and by warm and cold phases of El Niño Southern Oscillation. In Chapter 3 I evaluated the interactive effect of consumers on species richness, diversity and evenness of primary producers and discussed the results in the context of prevailing top down views on the regulation of marine tropical communities. I further discuss the importance to manage both top down and bottom up factors to maintain ecosystem structure and function at tropical locations. In chapter 4 I used resource and consumer-stress models to predict the outcome of plant animal interactions. I observed how the impact of herbivory on primary producers was exacerbated by thermal stress and reduced algal biomass at times of low productivity and high temperature; this pattern shifted as productivity increased and thermal stress relaxed, which led to herbivores increasing, not decreasing algal biomass. Finally, chapter 5 provides the main conclusions about our work. I put our work in context of past and present ecological theories. I also offer a framework to manage this system, oriented to increasing the resistance and resilience of this fragile ecosystem. Close

• 43. [Article] The Performance of Four Native Perennial Forb Species Along a Climate Gradient in Pacific Northwest Prairies

  To determine how Pacific Northwest prairies are influenced by local site factors versus. regional climate, we studied the reproduction, plant size, and density of sixteen natural populations of four perennial ...

  Citation × Citation Citation Abstract Copy Title: The Performance of Four Native Perennial Forb Species Along a Climate Gradient in Pacific Northwest Prairies Author: Hendricks, Lauren Year: 2016 To determine how Pacific Northwest prairies are influenced by local site factors versus. regional climate, we studied the reproduction, plant size, and density of sixteen natural populations of four perennial forb species native to Pacific Northwest prairies: Ranunculus austro-oreganus, Sidalcea malviflora spp. virgata, Microseris laciniata, and Eriophyllum lanatum. These populations were distributed along a 700 kilometer latitudinal gradient from southern Oregon to Whidbey Island, Washington. We found significant differences in plant size and reproduction among populations for all species, but correlations among edaphic and climate variables and plant size and reproduction were weak. Instead, density was more strongly correlated with both edaphic and climate variables, suggesting that this is a better indicator of long-term demographic processes. Although a few factors are important across species (e.g., nutrient availability and minimum temperature), response is idiosyncratic at the individual species level in Pacific Northwest prairies. Title: The Performance of Four Native Perennial Forb Species Along a Climate Gradient in Pacific Northwest Prairies Author: Hendricks, Lauren Year: 2016 To determine how Pacific Northwest prairies are influenced by local site factors versus. regional climate, we studied the reproduction, plant size, and density of sixteen natural populations of four perennial forb species native to Pacific Northwest prairies: Ranunculus austro-oreganus, Sidalcea malviflora spp. virgata, Microseris laciniata, and Eriophyllum lanatum. These populations were distributed along a 700 kilometer latitudinal gradient from southern Oregon to Whidbey Island, Washington. We found significant differences in plant size and reproduction among populations for all species, but correlations among edaphic and climate variables and plant size and reproduction were weak. Instead, density was more strongly correlated with both edaphic and climate variables, suggesting that this is a better indicator of long-term demographic processes. Although a few factors are important across species (e.g., nutrient availability and minimum temperature), response is idiosyncratic at the individual species level in Pacific Northwest prairies. Close

• 44. [Article] Climate change impacts on mountain snowpack presented in a knowledge to action framework

  Throughout many of the world’s mountain ranges snowpack accumulates during the winter and into the spring, providing a natural reservoir for water. As this reservoir melts, it fills streams and recharges ...

  Citation × Citation Citation Abstract Copy Title: Climate change impacts on mountain snowpack presented in a knowledge to action framework Author: Sproles, Eric Allan Throughout many of the world’s mountain ranges snowpack accumulates during the winter and into the spring, providing a natural reservoir for water. As this reservoir melts, it fills streams and recharges groundwater for over 1 billion people globally. Despite its importance to water resources, our understanding of the storage capacity of mountain snowpack is incomplete. This partial knowledge limits our abilities to assess the impact that projected climate conditions will have on mountain snowpack and water resources. While understanding the effect of projected climate on mountain snowpack is a global question, it can be best understood at the basin scale. It is at this level that decision makers and water resource managers base their decisions and require a clarified understanding of basin's mountain snowpack. The McKenzie River Basin located in the central-western Cascades of Oregon exhibits characteristics typical of many mountain river systems globally and in the Pacific Northwestern United States. Here snowmelt provides critical water supply for hydropower, agriculture, ecosystems, recreation, and municipalities. While there is a surplus of water in winter, the summer months see flows reach a minimum and the same groups have to compete for a limited supply. Throughout the Pacific Northwestern United States, current analyses and those of projected future climate change impacts show rising temperatures, diminished snowpacks, and declining summertime streamflow. The impacts of climate change on water resources presents new challenges and requires fresh approaches to understanding problems that are only beginning to be recognized. Climate change also presents challenges to decision makers who need new kinds of climate and water information, and will need the scientific research community to help provide improved means of knowledge transfer. This dissertation quantified the basin-wide distribution of snowpack across multiple decades in present and in projected climate conditions, describing a 56% decrease in mountain snowpack with regional projected temperature increases. These results were used to develop a probabilistic understanding of snowpack in projected climates. This section described a significant shift in statistical relations of snowpack. One that would be statistically likely to accumulate every 3 out of 4 years would accumulate in 1 out of 20 years. Finally this research identifies methods to improved knowledge transfer from the research community to water resource professionals. Implementation of these recommendations would enable a more effective means of dissemination to stakeholders and policy makers. While this research focused only on the McKenzie River Basin, it has regional applications. Processes affecting snowpack in the McKenzie River Basin are similar to those in many other maritime, forested Pacific Northwest watersheds. The framework of this research could also be applied to regions outside of the Pacific Northwestern United States to gain a similar level of understanding of climate impacts on mountain snowpack. Title: Climate change impacts on mountain snowpack presented in a knowledge to action framework Author: Sproles, Eric Allan Throughout many of the world’s mountain ranges snowpack accumulates during the winter and into the spring, providing a natural reservoir for water. As this reservoir melts, it fills streams and recharges groundwater for over 1 billion people globally. Despite its importance to water resources, our understanding of the storage capacity of mountain snowpack is incomplete. This partial knowledge limits our abilities to assess the impact that projected climate conditions will have on mountain snowpack and water resources. While understanding the effect of projected climate on mountain snowpack is a global question, it can be best understood at the basin scale. It is at this level that decision makers and water resource managers base their decisions and require a clarified understanding of basin's mountain snowpack. The McKenzie River Basin located in the central-western Cascades of Oregon exhibits characteristics typical of many mountain river systems globally and in the Pacific Northwestern United States. Here snowmelt provides critical water supply for hydropower, agriculture, ecosystems, recreation, and municipalities. While there is a surplus of water in winter, the summer months see flows reach a minimum and the same groups have to compete for a limited supply. Throughout the Pacific Northwestern United States, current analyses and those of projected future climate change impacts show rising temperatures, diminished snowpacks, and declining summertime streamflow. The impacts of climate change on water resources presents new challenges and requires fresh approaches to understanding problems that are only beginning to be recognized. Climate change also presents challenges to decision makers who need new kinds of climate and water information, and will need the scientific research community to help provide improved means of knowledge transfer. This dissertation quantified the basin-wide distribution of snowpack across multiple decades in present and in projected climate conditions, describing a 56% decrease in mountain snowpack with regional projected temperature increases. These results were used to develop a probabilistic understanding of snowpack in projected climates. This section described a significant shift in statistical relations of snowpack. One that would be statistically likely to accumulate every 3 out of 4 years would accumulate in 1 out of 20 years. Finally this research identifies methods to improved knowledge transfer from the research community to water resource professionals. Implementation of these recommendations would enable a more effective means of dissemination to stakeholders and policy makers. While this research focused only on the McKenzie River Basin, it has regional applications. Processes affecting snowpack in the McKenzie River Basin are similar to those in many other maritime, forested Pacific Northwest watersheds. The framework of this research could also be applied to regions outside of the Pacific Northwestern United States to gain a similar level of understanding of climate impacts on mountain snowpack. Close

• 45. [Article] Predicting landscape sensitivity to present and future floods in the Pacific Northwest, USA

  Supporting information is available online at: http://onlinelibrary.wiley.com/doi/10.1002/hyp.10553/suppinfo

  Citation × Citation Citation Abstract Copy Title: Predicting landscape sensitivity to present and future floods in the Pacific Northwest, USA Author: Lewis, Sarah L., Safeeq, Mohammad, Staab, Brian, Grant, Gordon E. Supporting information is available online at: http://onlinelibrary.wiley.com/doi/10.1002/hyp.10553/suppinfo Title: Predicting landscape sensitivity to present and future floods in the Pacific Northwest, USA Author: Lewis, Sarah L., Safeeq, Mohammad, Staab, Brian, Grant, Gordon E. Supporting information is available online at: http://onlinelibrary.wiley.com/doi/10.1002/hyp.10553/suppinfo Close

• 46. [Article] Climate Change: Natural Variability is a Big Deal Too!

  This is a presentation from The Oregon Water Conference 2011: Evaluating and Managing Water Resources in a Climate of Uncertainty Oregon State University – CH2M Hill Alumni Center – Corvallis, Oregon. OR ...

  Citation × Citation Citation Abstract Copy Title: Climate Change: Natural Variability is a Big Deal Too! Author: Curtis, David C., Prakash, Om Year: 2011 This is a presentation from The Oregon Water Conference 2011: Evaluating and Managing Water Resources in a Climate of Uncertainty Oregon State University – CH2M Hill Alumni Center – Corvallis, Oregon. OR Section, American Water Resources Association and OR Section, American Institute of Hydrology Title: Climate Change: Natural Variability is a Big Deal Too! Author: Curtis, David C., Prakash, Om Year: 2011 This is a presentation from The Oregon Water Conference 2011: Evaluating and Managing Water Resources in a Climate of Uncertainty Oregon State University – CH2M Hill Alumni Center – Corvallis, Oregon. OR Section, American Water Resources Association and OR Section, American Institute of Hydrology Close

• 47. [Article] Outcome Distributions in Impact Assessment : Climate Change and Technology Adoption in Pacific Northwest Agriculture

  Increased temperature and precipitation variability and frequent extreme weather events due to climate change pose a threat to farming operations and agricultural communities. The recent IPCC assessment ...

  Citation × Citation Citation Abstract Copy Title: Outcome Distributions in Impact Assessment : Climate Change and Technology Adoption in Pacific Northwest Agriculture Author: Zhang, Hongliang Increased temperature and precipitation variability and frequent extreme weather events due to climate change pose a threat to farming operations and agricultural communities. The recent IPCC assessment shows that the projected climate change will, on average, reduce wheat yields by 5% in temperate regions without adaptation and even more if temperatures continue to rise. Designing policies for helping climate-vulnerable farmers requires a comprehensive understanding of the impacts of climate change on agricultural systems and potential adaptation strategies. This dissertation consists of three essays that address several relevant issues from an economic perspective. The first essay presents an empirical analysis to assess the impacts of climate change on farm-level economic outcome distributions for winter wheat systems (including winter wheat yield, farm revenue, expenditure, and net return) in the U.S. Pacific Northwest by using a flexible moment-based approach. Results indicate that a warming climate, on average, reduces winter wheat yield but increases farm economic returns in this region, while droughts have a large negative impact on the ex-ante distributions of winter wheat yields and farm net returns. Using the econometric estimates, the farm-level climate vulnerability is quantified and examined. The second essay examines the effects of conservation tillage (including no-till and other conservation tillage) on winter wheat yield and production risk. We test the hypothesis that conservation tillage practices are risk-reducing. We use farm-level tillage practice data from the 2012 Agricultural Census for the U.S. Pacific Northwest. Results are estimated using a three-stage approach by integrating a multinomial logit model with a flexible moment-based approach. We find that conservation tillage has a negative effect on winter wheat productivity. We also find statistical evidence that conservation tillage is risk-increasing. Implications of the results for using conservation tillage to adapt to climate change are discussed. The third essay compares the difference-in-difference and fixed effects approaches to estimate long-term climate impacts versus short-term weather effects on U.S winter wheat systems. A county-level panel dataset is used to assess the effects of climate and weather variables on winter wheat yield and farm revenue in the U.S. Pacific Northwest and the central Great Plains. The net effect of a warming climate is found to be negative on the winter wheat production both in the short run and the long run. Implications of the results for short-term adjustments and long-term adaptations are discussed. Title: Outcome Distributions in Impact Assessment : Climate Change and Technology Adoption in Pacific Northwest Agriculture Author: Zhang, Hongliang Increased temperature and precipitation variability and frequent extreme weather events due to climate change pose a threat to farming operations and agricultural communities. The recent IPCC assessment shows that the projected climate change will, on average, reduce wheat yields by 5% in temperate regions without adaptation and even more if temperatures continue to rise. Designing policies for helping climate-vulnerable farmers requires a comprehensive understanding of the impacts of climate change on agricultural systems and potential adaptation strategies. This dissertation consists of three essays that address several relevant issues from an economic perspective. The first essay presents an empirical analysis to assess the impacts of climate change on farm-level economic outcome distributions for winter wheat systems (including winter wheat yield, farm revenue, expenditure, and net return) in the U.S. Pacific Northwest by using a flexible moment-based approach. Results indicate that a warming climate, on average, reduces winter wheat yield but increases farm economic returns in this region, while droughts have a large negative impact on the ex-ante distributions of winter wheat yields and farm net returns. Using the econometric estimates, the farm-level climate vulnerability is quantified and examined. The second essay examines the effects of conservation tillage (including no-till and other conservation tillage) on winter wheat yield and production risk. We test the hypothesis that conservation tillage practices are risk-reducing. We use farm-level tillage practice data from the 2012 Agricultural Census for the U.S. Pacific Northwest. Results are estimated using a three-stage approach by integrating a multinomial logit model with a flexible moment-based approach. We find that conservation tillage has a negative effect on winter wheat productivity. We also find statistical evidence that conservation tillage is risk-increasing. Implications of the results for using conservation tillage to adapt to climate change are discussed. The third essay compares the difference-in-difference and fixed effects approaches to estimate long-term climate impacts versus short-term weather effects on U.S winter wheat systems. A county-level panel dataset is used to assess the effects of climate and weather variables on winter wheat yield and farm revenue in the U.S. Pacific Northwest and the central Great Plains. The net effect of a warming climate is found to be negative on the winter wheat production both in the short run and the long run. Implications of the results for short-term adjustments and long-term adaptations are discussed. Close

• 48. [Article] Characterizing Linkages Between the Climate, Cryosphere, and Impacts on Run-of-River Hydropower in Data-Sparse Mountain Environments

  In many regions of the world, a significant portion of the surface water originates in mountain headwaters where the timing and magnitude of streamflow is largely dictated by the seasonal storage of precipitation ...

  Citation × Citation Citation Abstract Copy Title: Characterizing Linkages Between the Climate, Cryosphere, and Impacts on Run-of-River Hydropower in Data-Sparse Mountain Environments Author: Mosier, Thomas M. In many regions of the world, a significant portion of the surface water originates in mountain headwaters where the timing and magnitude of streamflow is largely dictated by the seasonal storage of precipitation as snowpack and long-term storage as glaciers. Accumulation, persistence, and melt of snow and ice are functions of the climate in which they exist and therefore respond to changes in that climate. One important use of water in many regions is for hydropower energy production. While reservoir-based hydropower infrastructure has some ability to absorb changes in timing of streamflow, run-of-river hydropower infrastructure does not. Thus, in assessing the economic feasibility of new or existing run-of-river infrastructure, it is important to account for potential impacts climate change may have over the lifetime of the project. Projecting impacts of climate change on surface water resources, and in particular on run-of-river hydropower resource potential, requires robustly characterizing the linkages between the climate, cryosphere, and streamflow. Two obstacles to increasing our understanding of mountain systems are the sparsity of observation data and complexity of weather patterns. The first part of my research addresses the issue of climate data availability in mountain regions through development of statistical models to characterize the high-spatial resolution distribution of historic and projected future precipitation and temperature. I demonstrate these climate products through projecting long-term changes in snowfall for the Alaska Range, Alps, Central Andes, and Himalaya-Karakoram-Hindu Kush ranges. I then present a framework for assessing conceptual cryosphere hydrology models and implement the framework for two long-term glacier study sites in Alaska, USA. Using this framework, I identify novel formulations for modeling the heat transfer and energy balance of snowpacks and glaciers that improve model robustness relative to the current generation of cryosphere hydrology models typically used in data-sparse mountain environments. I then demonstrate a method for understanding the impacts of projected future climate change on run-of-river hydropower resource potential, using Falls Creek in Oregon, USA as a test case. A core value of this work is producing models that can be straightforwardly applied to any region, thus decreasing the impacts of data disparities between regions on our ability to characterize climate change impacts on mountain regions. Title: Characterizing Linkages Between the Climate, Cryosphere, and Impacts on Run-of-River Hydropower in Data-Sparse Mountain Environments Author: Mosier, Thomas M. In many regions of the world, a significant portion of the surface water originates in mountain headwaters where the timing and magnitude of streamflow is largely dictated by the seasonal storage of precipitation as snowpack and long-term storage as glaciers. Accumulation, persistence, and melt of snow and ice are functions of the climate in which they exist and therefore respond to changes in that climate. One important use of water in many regions is for hydropower energy production. While reservoir-based hydropower infrastructure has some ability to absorb changes in timing of streamflow, run-of-river hydropower infrastructure does not. Thus, in assessing the economic feasibility of new or existing run-of-river infrastructure, it is important to account for potential impacts climate change may have over the lifetime of the project. Projecting impacts of climate change on surface water resources, and in particular on run-of-river hydropower resource potential, requires robustly characterizing the linkages between the climate, cryosphere, and streamflow. Two obstacles to increasing our understanding of mountain systems are the sparsity of observation data and complexity of weather patterns. The first part of my research addresses the issue of climate data availability in mountain regions through development of statistical models to characterize the high-spatial resolution distribution of historic and projected future precipitation and temperature. I demonstrate these climate products through projecting long-term changes in snowfall for the Alaska Range, Alps, Central Andes, and Himalaya-Karakoram-Hindu Kush ranges. I then present a framework for assessing conceptual cryosphere hydrology models and implement the framework for two long-term glacier study sites in Alaska, USA. Using this framework, I identify novel formulations for modeling the heat transfer and energy balance of snowpacks and glaciers that improve model robustness relative to the current generation of cryosphere hydrology models typically used in data-sparse mountain environments. I then demonstrate a method for understanding the impacts of projected future climate change on run-of-river hydropower resource potential, using Falls Creek in Oregon, USA as a test case. A core value of this work is producing models that can be straightforwardly applied to any region, thus decreasing the impacts of data disparities between regions on our ability to characterize climate change impacts on mountain regions. Close

• 49. [Article] Regional Scale Modeling of Climate, Cryosphere, and Freshwater Discharge in Changing Coastal Mountain Environments

  The glaciated coastal mountain watersheds that drain into the Gulf of Alaska (GOA) provide a model laboratory to explore the challenges of hydrological modeling and study the impact of climate and glacier ...

  Citation × Citation Citation Abstract Copy Title: Regional Scale Modeling of Climate, Cryosphere, and Freshwater Discharge in Changing Coastal Mountain Environments Author: Beamer, Jordan P. The glaciated coastal mountain watersheds that drain into the Gulf of Alaska (GOA) provide a model laboratory to explore the challenges of hydrological modeling and study the impact of climate and glacier cover change on regional hydrology. The region is data-sparse and contains a complex assemblage of topography and land cover, including a system of mountain glaciers that are retreating at some of the highest rates on Earth. The high rates of runoff from precipitation and glacial melt delivered by coastal rivers influence ocean circulation patterns, rates of global sea level rise, and provide spawning habitat for the large salmon populations. Physically-based hydrological modeling of the major water budget components of the GOA, driven using historical reanalysis weather data and land cover, reveals that the modeled water budget components, particularly precipitation input, vary widely between commonly-used weather products. The majority of the large freshwater flux into the GOA is derived from distributed coastal streams rather than the large inland rivers. The modeled seasonal aggregated GOA hydrograph is dominated by the spring and early summer snowmelt, and supplemented by late summer glacial ice melt. Model results demonstrate good agreement with NASA Gravity Recovery and Climate Experiment (GRACE) satellite data in terms of annual amplitudes and long term losses (ice loss), and suggest that existing GRACE solutions, previously reported to represent glacier mass balance alone, are actually measuring the full water budget of land and ice surfaces. An ensemble of climate models and future emissions scenarios were paired with systematically altered land cover to test the sensitivity of the hydrologic system to changes in regional climate patterns and glacier coverage representative of late twenty first century conditions. Compared with the hindcast simulations, the model results forced with increased regional air temperatures and precipitation inputs and reduced glacier cover produce an increase in the annual GOA freshwater discharge volume. The seasonal GOA hydrograph is flattened due to increased winter runoff from more winter rainfall and less snow accumulation, and lower levels of snowmelt and glacier ice contribution. Large uncertainties exist in the direction of change in the glacier runoff component, primarily due to uncertainties that exist in predicting glacier response to climate change. Hydrological modeling with high resolution and inclusion of relevant physical processes can produce significantly improved products that are of high value to and in demand by numerous other scientific communities. However, the value and accuracy of the output from the hydrologic model is highly dependent on the weather forcing quality. Given the considerable importance of quality weather forcing for hydrologic modeling, it is imperative to assess the suitability of multiple products by evaluating local and regional performance and accounting for uncertainty. Additional efforts should be made to improve the spatial resolution of the reanalysis through downscaling and to strategically increase the number of weather stations at high elevations and incorporate that data into weather forcing datasets. Title: Regional Scale Modeling of Climate, Cryosphere, and Freshwater Discharge in Changing Coastal Mountain Environments Author: Beamer, Jordan P. The glaciated coastal mountain watersheds that drain into the Gulf of Alaska (GOA) provide a model laboratory to explore the challenges of hydrological modeling and study the impact of climate and glacier cover change on regional hydrology. The region is data-sparse and contains a complex assemblage of topography and land cover, including a system of mountain glaciers that are retreating at some of the highest rates on Earth. The high rates of runoff from precipitation and glacial melt delivered by coastal rivers influence ocean circulation patterns, rates of global sea level rise, and provide spawning habitat for the large salmon populations. Physically-based hydrological modeling of the major water budget components of the GOA, driven using historical reanalysis weather data and land cover, reveals that the modeled water budget components, particularly precipitation input, vary widely between commonly-used weather products. The majority of the large freshwater flux into the GOA is derived from distributed coastal streams rather than the large inland rivers. The modeled seasonal aggregated GOA hydrograph is dominated by the spring and early summer snowmelt, and supplemented by late summer glacial ice melt. Model results demonstrate good agreement with NASA Gravity Recovery and Climate Experiment (GRACE) satellite data in terms of annual amplitudes and long term losses (ice loss), and suggest that existing GRACE solutions, previously reported to represent glacier mass balance alone, are actually measuring the full water budget of land and ice surfaces. An ensemble of climate models and future emissions scenarios were paired with systematically altered land cover to test the sensitivity of the hydrologic system to changes in regional climate patterns and glacier coverage representative of late twenty first century conditions. Compared with the hindcast simulations, the model results forced with increased regional air temperatures and precipitation inputs and reduced glacier cover produce an increase in the annual GOA freshwater discharge volume. The seasonal GOA hydrograph is flattened due to increased winter runoff from more winter rainfall and less snow accumulation, and lower levels of snowmelt and glacier ice contribution. Large uncertainties exist in the direction of change in the glacier runoff component, primarily due to uncertainties that exist in predicting glacier response to climate change. Hydrological modeling with high resolution and inclusion of relevant physical processes can produce significantly improved products that are of high value to and in demand by numerous other scientific communities. However, the value and accuracy of the output from the hydrologic model is highly dependent on the weather forcing quality. Given the considerable importance of quality weather forcing for hydrologic modeling, it is imperative to assess the suitability of multiple products by evaluating local and regional performance and accounting for uncertainty. Additional efforts should be made to improve the spatial resolution of the reanalysis through downscaling and to strategically increase the number of weather stations at high elevations and incorporate that data into weather forcing datasets. Close

• 50. [Article] Climate shifts the interaction web of a marine plankton community

  This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons, Inc. and can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-2486. This article ...

  Citation × Citation Citation Abstract Copy Title: Climate shifts the interaction web of a marine plankton community Author: Tolimieri, Nick, Francis, Tessa B., Peterson, William T., Scheuerell, Mark D., Ruzicka, James J., Brodeur, Richard D., Levin, Phillip S. This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons, Inc. and can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-2486. This article is a U.S. Government work and is in the public domain in the U.S.A. Title: Climate shifts the interaction web of a marine plankton community Author: Tolimieri, Nick, Francis, Tessa B., Peterson, William T., Scheuerell, Mark D., Ruzicka, James J., Brodeur, Richard D., Levin, Phillip S. This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons, Inc. and can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-2486. This article is a U.S. Government work and is in the public domain in the U.S.A. Close