AUTHORS: David Theobald*, Conservation Science Partners; David Merritt, USDA Forest Service; Ian Leinwand, Conservation Science Partners
ABSTRACT: Riparian ecosystems are important landscape features, particularly in arid regions, because of the disproportionate biodiversity found in them. Riparian ecosystems are also important because they naturally connecting broader landscapes across ecological gradients, and hence they are key to climate change adaptation. Assessing riparian ecosystems at regional extents remains challenging because the fine-scale of riparian features, as well as the multitude of human land uses that stress these ecosystems. Because climate change has increasingly altered important ecological processes that drive riparian ecosystems, characterizing the geomorphic setting in which these processes operate, particularly longitudinal and lateral connectivity, is key. Here we describe our methods to map valley bottoms in the western US and characterize them using the Hydro-Geomorphological Valley Bottom classification. We found that reservoirs can store between 16% to 200+% of the annual stream discharge delivered to streams, and that about 15% of the West’s valley riparian areas are modified by roads, development, or agriculture.
