A framework for understanding the hydroecology of impacted wet meadows in the Sierra Nevada and Cascade Ranges, California, USA

摘要: Meadows of the Sierra Nevada and Cascade mountains California, USA, support diverse highly productive wet-meadow vegetation dominated by sedges, rushes, grasses, other herbaceous species. These groundwater–dependent ecosystems rely on persistence a shallow water table throughout dry summer. Case studies Bear Creek, Last Chance, Tuolumne meadow are used to create conceptual framework describing groundwater–ecosystem connections in this environment. The requirements for at each site represented as water-table-depth hydrograph; however, these hydrographs were found vary among sites. Causes variation include (1) differences soil texture, which govern capillary effects availability vadose (2) elevation-controlled climate that affect phenology vegetation. field observations show spatial water-table depth exerts strong control composition patterning. Groundwater-flow modeling demonstrates lower hydraulic-conductivity sediments, higher groundwater-inflow rates, ratio lateral basal-groundwater inflow all encourage high vegetation, particularly margin meadow, even cases with moderate stream incision.