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Articles 1 - 7 of 7

Full-Text Articles in Physical Sciences and Mathematics

Sampling Bias Overestimates Climate Change Impacts On Forest Growth In The Southwestern United States, Stefan Klesse, R. Justin Derose, Christopher H. Guiterman, Ann M. Lynch, Christopher D. O’Connor, John D. Shaw, Margaret E.K. Evans Dec 2018

Sampling Bias Overestimates Climate Change Impacts On Forest Growth In The Southwestern United States, Stefan Klesse, R. Justin Derose, Christopher H. Guiterman, Ann M. Lynch, Christopher D. O’Connor, John D. Shaw, Margaret E.K. Evans

Wildland Resources Faculty Publications

Climate−tree growth relationships recorded in annual growth rings have recently been the basis for projecting climate change impacts on forests. However, most trees and sample sites represented in the International Tree-Ring Data Bank (ITRDB) were chosen to maximize climate signal and are characterized by marginal growing conditions not representative of the larger forest ecosystem. We evaluate the magnitude of this potential bias using a spatially unbiased tree-ring network collected by the USFS Forest Inventory and Analysis (FIA) program. We show that U.S. Southwest ITRDB samples overestimate regional forest climate sensitivity by 41–59%, because ITRDB trees were sampled at warmer and …


Assessment Of The Effects Of Climate Change On Evapotranspiration With An Improved Elasticity Method In A Nonhumid Area, Lei Tian, Jiming Jin, Pute Wu, Guo-Yue Niu Dec 2018

Assessment Of The Effects Of Climate Change On Evapotranspiration With An Improved Elasticity Method In A Nonhumid Area, Lei Tian, Jiming Jin, Pute Wu, Guo-Yue Niu

Watershed Sciences Faculty Publications

Climatic elasticity is a crucial metric to assess the hydrological influence of climate change. Based on the Budyko equation, this study performed an analytical derivation of the climatic elasticity of evapotranspiration (ET). With this derived elasticity, it is possible to quantitatively separate the impacts of precipitation, air temperature, net radiation, relative humidity, and wind speed on ET in a watershed. This method was applied in the Wuding River Watershed (WRW), located in the center of the Yellow River Watershed of China. The estimated rate of change in ET caused by climatic variables is −10.69 mm/decade, which is close to the …


Quantifying The Impact Of Climate Change And Human Activities On Streamflow In A Semi-Arid Watershed With The Budyko Equation Incorporating Dynamic Vegetation Information, Lei Tian, Jiming Jin, Pute Wu, Guo-Yue Niu Dec 2018

Quantifying The Impact Of Climate Change And Human Activities On Streamflow In A Semi-Arid Watershed With The Budyko Equation Incorporating Dynamic Vegetation Information, Lei Tian, Jiming Jin, Pute Wu, Guo-Yue Niu

Watershed Sciences Faculty Publications

Understanding hydrological responses to climate change and land use and land cover change (LULCC) is important for water resource planning and management, especially for water-limited areas. The annual streamflow of the Wuding River Watershed (WRW), the largest sediment source of the Yellow River in China, has decreased significantly over the past 50 years at a rate of 5.2 mm/decade. Using the Budyko equation, this study investigated this decrease with the contributions from climate change and LULCC caused by human activities, which have intensified since 1999 due to China’s Grain for Green Project (GFGP). The Budyko parameter that represents watershed characteristics …


Climate Change Perceptions And Adaptation Among Small-Scale Farmers In Uganda: A Community-Based Participatory Approach, Thomas Derr Dec 2018

Climate Change Perceptions And Adaptation Among Small-Scale Farmers In Uganda: A Community-Based Participatory Approach, Thomas Derr

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate change in the East African country of Uganda is causing severe variations in the once predictable seasonal weather patterns that farmers had come to depend on. This, in combination with social and economic challenges, has significantly increased the vulnerability of farmers who make up the majority of Uganda’s population. Previous knowledge and observations suggest that Ugandan farmers may be reluctant or slow to change their practices in response to the changing climate. Strategies are therefore needed to identify challenges and sustainable solutions. This research used qualitative data collection methods known as participatory rural appraisal (PRA) and participatory action research …


Waterfall Formation At A Desert River-Reservoir Delta Isolates Endangered Fishes, Charles N. Cathcart, Casey A. Pennock, Christopher A. Cheek, Mark C. Mckinstry, Peter D. Mackinnon, Mary M. Conner, Keith B. Gido Sep 2018

Waterfall Formation At A Desert River-Reservoir Delta Isolates Endangered Fishes, Charles N. Cathcart, Casey A. Pennock, Christopher A. Cheek, Mark C. Mckinstry, Peter D. Mackinnon, Mary M. Conner, Keith B. Gido

Wildland Resources Faculty Publications

Unforeseen interactions of dams and declining water availability have formed new obstacles to recovering endemic and endangered big-river fishes. During a recent trend of drying climate and declining reservoir water levels in the southwestern United States, a large waterfall has formed on two separate occasions (1989-1995 & 2001-present) in the transition zone between the San Juan River and Lake Powell reservoir because of deposited sediments. Because recovery plans for two large-bodied endangered fish species, razorback sucker (Xyrauchen texanus) and Colorado pikeminnow (Ptychocheilus lucius), include annual stockings in the San Juan River, this waterfall potentially blocks upstream …


The Effect Of Warmer Winters On The Demography Of An Outbreak Insect Is Hidden By Intraspecific Competition, Devin W. Goodsman, Guenchik Grosklos, Brian H. Aukema, Caroline Whitehouse, Katherine P. Bleiker, Nate G. Mcdowell, Richard S. Middleton, Chonggang Xu May 2018

The Effect Of Warmer Winters On The Demography Of An Outbreak Insect Is Hidden By Intraspecific Competition, Devin W. Goodsman, Guenchik Grosklos, Brian H. Aukema, Caroline Whitehouse, Katherine P. Bleiker, Nate G. Mcdowell, Richard S. Middleton, Chonggang Xu

Mathematics and Statistics Faculty Publications

Warmer climates are predicted to increase bark beetle outbreak frequency, severity, and range. Even in favorable climates, however, outbreaks can decelerate due to resource limitation, which necessitates the inclusion of competition for limited resources in analyses of climatic effects on populations. We evaluated several hypotheses of how climate impacts mountain pine beetle reproduction using an extensive 9‐year dataset, in which nearly 10,000 trees were sampled across a region of approximately 90,000 km2, that was recently invaded by the mountain pine beetle in Alberta, Canada. Our analysis supports the hypothesis of a positive effect of warmer winter temperatures on …


Phenological Mismatch In Coastal Western Alaska May Increase Summer Season Greenhouse Gas Uptake, Katharine C. Kelsey, A. Joshua Leffler, Karen H. Beard, Ryan T. Choi, Joel A. Schmutz, Jeffery M. Welker Apr 2018

Phenological Mismatch In Coastal Western Alaska May Increase Summer Season Greenhouse Gas Uptake, Katharine C. Kelsey, A. Joshua Leffler, Karen H. Beard, Ryan T. Choi, Joel A. Schmutz, Jeffery M. Welker

Wildland Resources Faculty Publications

High latitude ecosystems are prone to phenological mismatches due to climate change- driven advances in the growing season and changing arrival times of migratory herbivores. These changes have the potential to alter biogeochemical cycling and contribute to feedbacks on climate change by altering greenhouse gas (GHG) emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) through large regions of the Arctic. Yet the effects of phenological mismatches on gas fluxes are currently unexplored. We used a three-year field experiment that altered the start of the growing season and timing of grazing to …