Understanding relationships among climate, stream channel dynamics, and riparian vegetation establishment during the past 50 years in upland central Nevada watersheds.

摘要

Historical stream gaging data was used to examine patterns of recent stream channel incision in seven upland watersheds in central Nevada. Research objectives were to quantify the timing and magnitude of incision in each basin, and relate incision episodes to hydrologic fluctuations. Research also examined woody riparian vegetation establishment in five study basins. Results suggest that recent channel adjustments are temporally and spatially variable within and among basins, and correlated with high flows. Response may be influenced by valley morphology, debris dams, alluvial fans, vegetation, and sediment characteristics. High flow events correlated with establishment occurred during the 1960s, 1970s, and 1980s. Statistical analyses revealed strong relationships between hydroclimatic variables and establishment. High establishment may result from the creation of bare, moist germination surfaces (high flows), followed by lower flows that do not disturb seedlings but maintain moisture requirements. Low establishment may be related to drought periods in years following establishment.