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• 1. [Article] Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin Using the Precipitation Runoff Modeling System

  This study provides an analysis of watershed response to climate change and forest fire impacts, to better understand the hydrologic budget and inform water management decisions for present and future ...

  Citation × Citation Citation Abstract Copy Title: Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin Using the Precipitation Runoff Modeling System Author: Yazzie, Kimberly Crystal Year: 2016 This study provides an analysis of watershed response to climate change and forest fire impacts, to better understand the hydrologic budget and inform water management decisions for present and future needs. The study site is 2,365 km2, located in the upper Umatilla River Basin (URB) in northeastern Oregon. The Precipitation Runoff Modeling System, a distributed-parameter, physical-process watershed model, was used in this study. Model calibration yielded a Nash Sutcliffe Model Efficiency of 0.73 for both calibration (1995-2010) and validation (2010-2014) of daily streamflow. Ten Global Climate Models using Coupled Model Intercomparison Project Phase 5 experiments with Representative Concentration Pathways 4.5 and 8.5 (RCP), were used to observe hydrologic regime shifts in the 2020s, 2050s, and 2080s. Mean center timing of flow occurs earlier in the year in both pre- and post-fire conditions, where there are increased winter flows and decreased summer flows throughout the 21st century. Change in temperature and percent change in precipitation is more variable in the summer than winter increasing over time, with a slight decrease in winter precipitation in the 2080s in RCP 8.5. Temperature increases 1.6°C in RCP 4.5 and 3.3°C in RCP 8.5 by the end of the 21st century. The ratio of Snow Water Equivalent to Precipitation decreases 96% in the 2080s in RCP 8.5 before forest cover reduction, and decreases 90-99% after forest cover reduction. Potential basin recharge and the base-flow index are both sustained throughout the 21st century with slight declines before forest cover reduction, with an increase in basin recharge and increase in base-flows in the 2080s after fire-burns. However, the simulated sustained base-flows and area-weighted basin recharge in this study, do not take into account the complex geologic structure of the Columbia River Basalt Group (CRBG). A more robust characterization and simulation of URB aquifer recharge would involve coupling the PRMS model with a groundwater model in a future study. Although groundwater recharge in the CRBG in the URB is not well understood, the long-term decline of groundwater storage presents a serious environmental challenge for the Confederated Tribes of the Umatilla Indian Reservation and communities in the URB. Title: Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin Using the Precipitation Runoff Modeling System Author: Yazzie, Kimberly Crystal Year: 2016 This study provides an analysis of watershed response to climate change and forest fire impacts, to better understand the hydrologic budget and inform water management decisions for present and future needs. The study site is 2,365 km2, located in the upper Umatilla River Basin (URB) in northeastern Oregon. The Precipitation Runoff Modeling System, a distributed-parameter, physical-process watershed model, was used in this study. Model calibration yielded a Nash Sutcliffe Model Efficiency of 0.73 for both calibration (1995-2010) and validation (2010-2014) of daily streamflow. Ten Global Climate Models using Coupled Model Intercomparison Project Phase 5 experiments with Representative Concentration Pathways 4.5 and 8.5 (RCP), were used to observe hydrologic regime shifts in the 2020s, 2050s, and 2080s. Mean center timing of flow occurs earlier in the year in both pre- and post-fire conditions, where there are increased winter flows and decreased summer flows throughout the 21st century. Change in temperature and percent change in precipitation is more variable in the summer than winter increasing over time, with a slight decrease in winter precipitation in the 2080s in RCP 8.5. Temperature increases 1.6°C in RCP 4.5 and 3.3°C in RCP 8.5 by the end of the 21st century. The ratio of Snow Water Equivalent to Precipitation decreases 96% in the 2080s in RCP 8.5 before forest cover reduction, and decreases 90-99% after forest cover reduction. Potential basin recharge and the base-flow index are both sustained throughout the 21st century with slight declines before forest cover reduction, with an increase in basin recharge and increase in base-flows in the 2080s after fire-burns. However, the simulated sustained base-flows and area-weighted basin recharge in this study, do not take into account the complex geologic structure of the Columbia River Basalt Group (CRBG). A more robust characterization and simulation of URB aquifer recharge would involve coupling the PRMS model with a groundwater model in a future study. Although groundwater recharge in the CRBG in the URB is not well understood, the long-term decline of groundwater storage presents a serious environmental challenge for the Confederated Tribes of the Umatilla Indian Reservation and communities in the URB. Close

• 2. [Article] Climate Change Impact on Drought Risk and Uncertainty in the Willamette River Basin

  Climate change due to global warming could induce more frequent droughts in the Willamette River Basin because less snowfall in winter and earlier snowmelt due to temperature increase may lead to decreases ...

  Citation × Citation Citation Abstract Copy Title: Climate Change Impact on Drought Risk and Uncertainty in the Willamette River Basin Author: Chang, Heejun, Jung, Il-Won Year: 2011 Climate change due to global warming could induce more frequent droughts in the Willamette River Basin because less snowfall in winter and earlier snowmelt due to temperature increase may lead to decreases in spring and summer streamflow. This study examines possible changes in drought risk using two drought indices, Standardized Precipitation Index (SPI) and Standardized Runoff Index (SRI). SPI represents a climatological drought index that considers only precipitation change, while SRI is a hydrological drought index that considers water balance change. In rainfall-dominated regions in the Willamette Valley, SPI is a useful drought index. In snow-dominated regions in the High Cascades, SRI can show more realistic drought risk change because SRI can represent snowmelt and geology effects. Our results show that the Willamette Valley is more vulnerable to drought risk than the High Cascades in the 21st century. SPI shows increasing frequency and intensity of short-term drought over the whole Willamette River basin due to summer precipitation decrease, while SRI in the High Cascades shows no change because the High Cascades have young permeable volcanic rocks and gentle slopes, which create a deep groundwater system. Additionally, the frequency of short-term extreme drought, such as droughts lasting 1 to 3 months, is projected to increase in the Willamette Valley, but long-term extreme droughts are not expected to change significantly. The increase in short-term extreme droughts is attributed to decreases in summer precipitation, and the lack of change in long-term extreme droughts is caused by increased winter runoff prompted by earlier snowmelt and winter precipitation increases. Title: Climate Change Impact on Drought Risk and Uncertainty in the Willamette River Basin Author: Chang, Heejun, Jung, Il-Won Year: 2011 Climate change due to global warming could induce more frequent droughts in the Willamette River Basin because less snowfall in winter and earlier snowmelt due to temperature increase may lead to decreases in spring and summer streamflow. This study examines possible changes in drought risk using two drought indices, Standardized Precipitation Index (SPI) and Standardized Runoff Index (SRI). SPI represents a climatological drought index that considers only precipitation change, while SRI is a hydrological drought index that considers water balance change. In rainfall-dominated regions in the Willamette Valley, SPI is a useful drought index. In snow-dominated regions in the High Cascades, SRI can show more realistic drought risk change because SRI can represent snowmelt and geology effects. Our results show that the Willamette Valley is more vulnerable to drought risk than the High Cascades in the 21st century. SPI shows increasing frequency and intensity of short-term drought over the whole Willamette River basin due to summer precipitation decrease, while SRI in the High Cascades shows no change because the High Cascades have young permeable volcanic rocks and gentle slopes, which create a deep groundwater system. Additionally, the frequency of short-term extreme drought, such as droughts lasting 1 to 3 months, is projected to increase in the Willamette Valley, but long-term extreme droughts are not expected to change significantly. The increase in short-term extreme droughts is attributed to decreases in summer precipitation, and the lack of change in long-term extreme droughts is caused by increased winter runoff prompted by earlier snowmelt and winter precipitation increases. Close

• 3. [Article] Fire Modulates Climate Change Response of Simulated Aspen Distribution Across Topoclimatic Gradients in a Semi-Arid Montane Landscape

  Content Changing aspen distribution in response to climate change and fire is a major focus of biodiversity conservation, yet little is known about the potential response of aspen to these two driving ...

  Citation × Citation Citation Abstract Copy Title: Fire Modulates Climate Change Response of Simulated Aspen Distribution Across Topoclimatic Gradients in a Semi-Arid Montane Landscape Author: Yang, Jian, Weisberg, Peter J., Shinneman, Douglas J., Dilts, Thomas E., Earnst, Susan L., Scheller, Robert M. Year: 2015 Content Changing aspen distribution in response to climate change and fire is a major focus of biodiversity conservation, yet little is known about the potential response of aspen to these two driving forces along topoclimatic gradients. Objective This study is set to evaluate how aspen distribution might shift in response to different climate-fire scenarios in a semi-arid montane landscape, and quantify the influence of fire regime along topoclimatic gradients. Methods We used a novel integration of a forest landscape succession and disturbance model (LAN DIS-II) with a fine-scale climatic water deficit approach to simulate dynamics of aspen and associated conifer and shrub species over the next 150 years under various climate-fire scenarios. Results Simulations suggest that many aspen stands could persist without fire for centuries under current climate conditions. However, a simulated 2–5ºC increase in temperature caused a substantial reduction of aspen coverage at lower elevations and a modest increase at upper elevations, leading to an overall reduction of aspen range at the landscape level. Increasing fire activity may favor aspen increase at its upper elevation limits adjacent to coniferous forest, but may also favor reduction of aspen at lower elevation limits adjacent to xeric shrubland. Conclusions Our study highlights the importance of incorporating fine-scale terrain effects on climatic water deficit and ecohydrology when modeling species distribution response to climate change. This modeling study suggests that climate mitigation and adaptation strategies that use fire would benefit from consideration of spatial context at landscape scales. Title: Fire Modulates Climate Change Response of Simulated Aspen Distribution Across Topoclimatic Gradients in a Semi-Arid Montane Landscape Author: Yang, Jian, Weisberg, Peter J., Shinneman, Douglas J., Dilts, Thomas E., Earnst, Susan L., Scheller, Robert M. Year: 2015 Content Changing aspen distribution in response to climate change and fire is a major focus of biodiversity conservation, yet little is known about the potential response of aspen to these two driving forces along topoclimatic gradients. Objective This study is set to evaluate how aspen distribution might shift in response to different climate-fire scenarios in a semi-arid montane landscape, and quantify the influence of fire regime along topoclimatic gradients. Methods We used a novel integration of a forest landscape succession and disturbance model (LAN DIS-II) with a fine-scale climatic water deficit approach to simulate dynamics of aspen and associated conifer and shrub species over the next 150 years under various climate-fire scenarios. Results Simulations suggest that many aspen stands could persist without fire for centuries under current climate conditions. However, a simulated 2–5ºC increase in temperature caused a substantial reduction of aspen coverage at lower elevations and a modest increase at upper elevations, leading to an overall reduction of aspen range at the landscape level. Increasing fire activity may favor aspen increase at its upper elevation limits adjacent to coniferous forest, but may also favor reduction of aspen at lower elevation limits adjacent to xeric shrubland. Conclusions Our study highlights the importance of incorporating fine-scale terrain effects on climatic water deficit and ecohydrology when modeling species distribution response to climate change. This modeling study suggests that climate mitigation and adaptation strategies that use fire would benefit from consideration of spatial context at landscape scales. Close

• 4. [Article] Evaluating Simplistic Methods to Understand Current Distributions and Forecast Distribution Changes Under Climate Change Scenarios: An Example With Coypu (Myocastor coypus)

  Invasive species provide a unique opportunity to evaluate factors controlling biogeographic distributions; we can consider introduction success as an experiment testing suitability of environmental conditions. ...

  Citation × Citation Citation Abstract Copy Title: Evaluating Simplistic Methods to Understand Current Distributions and Forecast Distribution Changes Under Climate Change Scenarios: An Example With Coypu (Myocastor coypus) Author: Jarnevich, Catherine S., Young, Nicholas E., Sheffels, Trevor R., Carter, Jacoby, Sytsma, Mark D., Talbert, Colin Year: 2017 Invasive species provide a unique opportunity to evaluate factors controlling biogeographic distributions; we can consider introduction success as an experiment testing suitability of environmental conditions. Predicting potential distributions of spreading species is not easy, and forecasting potential distributions with changing climate is even more difficult. Using the globally invasive coypu (Myocastor coypus [Molina, 1782]), we evaluate and compare the utility of a simplistic ecophysiological based model and a correlative model to predict current and future distribution. The ecophysiological model was based on winter temperature relationships with nutria survival. We developed correlative statistical models using the Software for Assisted Habitat Modeling and biologically relevant climate data with a global extent. We applied the ecophysiological based model to several global circulation model (GCM) predictions for mid-century. We used global coypu introduction data to evaluate these models and to explore a hypothesized physiological limitation, finding general agreement with known coypu distribution locally and globally and support for an upper thermal tolerance threshold. Global circulation model based model results showed variability in coypu predicted distribution among GCMs, but had general agreement of increasing suitable area in the USA. Our methods highlighted the dynamic nature of the edges of the coypu distribution due to climate non-equilibrium, and uncertainty associated with forecasting future distributions. Areas deemed suitable habitat, especially those on the edge of the current known range, could be used for early detection of the spread of coypu populations for management purposes. Combining approaches can be beneficial to predicting potential distributions of invasive species now and in the future and in exploring hypotheses of factors controlling distributions. Title: Evaluating Simplistic Methods to Understand Current Distributions and Forecast Distribution Changes Under Climate Change Scenarios: An Example With Coypu (Myocastor coypus) Author: Jarnevich, Catherine S., Young, Nicholas E., Sheffels, Trevor R., Carter, Jacoby, Sytsma, Mark D., Talbert, Colin Year: 2017 Invasive species provide a unique opportunity to evaluate factors controlling biogeographic distributions; we can consider introduction success as an experiment testing suitability of environmental conditions. Predicting potential distributions of spreading species is not easy, and forecasting potential distributions with changing climate is even more difficult. Using the globally invasive coypu (Myocastor coypus [Molina, 1782]), we evaluate and compare the utility of a simplistic ecophysiological based model and a correlative model to predict current and future distribution. The ecophysiological model was based on winter temperature relationships with nutria survival. We developed correlative statistical models using the Software for Assisted Habitat Modeling and biologically relevant climate data with a global extent. We applied the ecophysiological based model to several global circulation model (GCM) predictions for mid-century. We used global coypu introduction data to evaluate these models and to explore a hypothesized physiological limitation, finding general agreement with known coypu distribution locally and globally and support for an upper thermal tolerance threshold. Global circulation model based model results showed variability in coypu predicted distribution among GCMs, but had general agreement of increasing suitable area in the USA. Our methods highlighted the dynamic nature of the edges of the coypu distribution due to climate non-equilibrium, and uncertainty associated with forecasting future distributions. Areas deemed suitable habitat, especially those on the edge of the current known range, could be used for early detection of the spread of coypu populations for management purposes. Combining approaches can be beneficial to predicting potential distributions of invasive species now and in the future and in exploring hypotheses of factors controlling distributions. Close