Results of Biological Investigations from the Lower Virgin River Vegetation Management Study

摘要

The exotic salt cedar (Tamarix chinensis) has been identified as a widespread, dominant phreatophyte along many riparian flood plains in the Western States. Many problems have been documented as a result of the invasion by salt cedar including extremely high-water consumption, tendency to concentrate salts, acting as a flood stream impediment, and providing poor wildlife habitat. In 1982, the Lower Virgin River Vegetation Management Study was initiated to determine if clearing phreatophytic vegetation and planting less water consumptive species would result in measurable water savings. From June 1982 to December 1983, the value of salt cedar habitat for wildlife was assessed on a 600-acre study site along the Lower Virgin River in Nevada. Vegetation characteristics in the salt cedar study area are best described as a monotypic growth of bushy, multistemmed trees possessing little foliage volume about 10 feet and with moderately dense foliage volume at the 6-inch to 2-foot level. Permanent resident bird species such as the Song Sparrow, Bewick's Wren, and Aberts's Towhee occurred at higher densities throughout all months of the year than the migrant, summer breeding, or wintering species. Detailed recommendations for maximizing successful revegetation plans were based on prior studies of native plants and agricultural crops.