Collaborative Research: EAR-Climate: Ecohydrological responses to climate change: Changing flowpaths, aging groundwaters, and alterations to aquatic ecosystems

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This project will advance understanding of how decreased groundwater recharge associated with climate change affects mountain groundwater systems and groundwater-dependent ecosystems. Mountain aquifers across the western United States serve as regional short-term storage reservoirs that provide a stable water supply for agricultural activities, nearby cities, and threatened ecological communities. Project activities will occur in the Sierra Nevada Sagehen Experimental Forest (SEF) and include field hydrological, geochemical, ecological community analysis of springs and an assessment of indicators of ecosystem stress. In the SEF, spring groundwater age was previously correlated with increased chemical weathering and ecosystem richness. These observations serve as an important baseline of hydrological and ecological health for comparison with modern observations. Broader impacts from this work focus on three areas: 1) strengthening personnel development by supporting undergraduate researchers and collaboration between two early career scientists; 2) supporting ongoing community science efforts through engagement with the annual BioBlitz event at the SEF; and 3) supporting K-12 STEM education through the development of a “Green Box” focused on project discoveries in collaboration with the Desert Research Institute’s Science Alive team.This project will investigate how decreased precipitation and increased temperature in the SEF have altered the distribution of contributing flowpaths to springflow generation. The research plan includes two years of spring hydrological sampling in the SEF for a suite of geochemical analytes, groundwater age tracers, and physical spring characteristics. The project will also investigate how benthic macroinvertebrate communities (BMI), including endemic and relic species, in the SEF have changed over the last 30 years, how these changes relate to flowpath changes, and how broader BMI community structures relate to modern hydrological and geochemical characteristics. The research will use ecological and stable isotopic analysis of BMI to reveal community structures and food web dynamics. This research will identify indicators that reveal impending collapse (i.e., hydroecological thresholds) of perennial springflow and groundwater-dependent ecological niches in mountain groundwater systems. This award is co-funded by the Hydrologic Sciences and Ecosystem Sciences programs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.