Major Basins of South America

Freshwater Ecoregions of the World, (FEOW) provides a new global biogeographic regionalization of the Earth's freshwater biodiversity. Covering virtually all freshwater habitats on Earth, this first-ever ecoregion map, together with associated species data, is a useful tool for underpinning global and regional conservation planning efforts, particularly to identify outstanding and imperiled freshwater systems; for serving as a logical framework for large-scale conservation strategies; and for providing a global-scale knowledge base for increasing freshwater biogeographic literacy. The freshwater ecoregion map encompasses 426 units, whose boundaries generally - though not always - correspond with those of watersheds (also known as drainage basins or catchments). Within individual ecoregions there will be turnover of species, such as when moving up or down a river system, but taken as a whole an ecoregion will typically have a distinct evolutionary history and/or ecological processes. Ecoregions are delineated based on the best available information, but data describing freshwater species and ecological processes are characterized by marked gaps and variation in quality, and improved information in the future may warrant map revisions.