Riparian areas are conspicuous belts of dense, green vegetation along streams and rivers. In the West, riparian areas tend to have higher levels of species diversity, richness, and population densities than adjacent vegetation types, making them of high value to managers, scientists, and the public. Riparian areas cover less than 2 percent of land area in the Southwestern United States. However, more than 50 percent of 166 species of breeding birds in the lowlands of the Southwest are completely dependent on these habitats. In Grand Canyon, besides serving as wildlife habitat, riparian shrubs and trees provide shade to whitewater recreationists and hikers in hot summer months.
Riparian plant research in Grand Canyon began in the early 1900s, and USGS Grand Canyon Monitoring and Research Center scientists and their cooperators continue to document the amount and types of vegetation found along the river corridor. The long-term goal for monitoring riparian vegetation in the Colorado River is to use biannual data on plant cover, species richness, and diversity in concert with semi-decadal vegetation mapping data to distinguish between the effects of dam operations and climate on changes in riparian vegetation. Large-scale trend detection at the reach or regional scale will provide information about gains or losses in vegetated area and about the vegetation classes that change the most. Knowing the status of riparian vegetation along the Colorado River is important because changes in riparian plant communities affect the wildlife in Grand Canyon and recreational hiking and rafting.
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