Ecosystems Three riparian ecosystems, delineated by elevation, are recognized in the arid and semi-arid southwestern United States and northern Mexico. Riparian vegetation that occurs along the flood plain of stream channels are typically composed of herbaceous species of Carex , Eleocharis , Juncus , and Scirpus and produce the characteristic dark green edge along the channel systems. Above 7,000 ft, herbaceous species of Carex , Eleocharis , Juncus , and Scirpus predominate along the edge of the stream channels. Riparian ecosystems between 3,500 and 7,000 ft contain the greatest number of plant species and the greatest canopy cover. Because of the abundance of water, plants, and animals, riparian areas provide valuable recreation opportunities as well as forage for livestock and wildlife in an otherwise arid environment.
Riparian ecosystems are prime habitats for many game and non-game species of wildlife and fish.
Collectively, climatic characteristics of riparian ecosystems exhibit a wide range of conditions due to large elevational differences and distributions of associated mountain ranges and highlands. The key characteristic of the riparian system is the availability of water throughout the year or at least during the growing season. Soils at the higher elevations generally consist of consolidated or unconsolidated alluvial sediments from parent materials of the surrounding uplands. Soil depths vary in riparian ecosystems, depending upon the stream gradient, topographic setting, and parent materials. Soils on the flood plains at lower elevations consist of recent depositions, tend to be uniform within horizontal strata, and exhibit little development.