West Mojave Plan FEIR/S - Desert Managers Group

emoved are in the area of Lucerne Valley, El Mirage, and Harper Lake.The amount of water in the Mojave River varies greatly from year to year. As measuredat the Forks, it has been more than 300,000 acre-feet one year and less than 10,000 acre-feetanother.The Mojave Water Agency was formed by an act of the State legislature in 1960 to findways to supplement the natural water supply. The agency has contracts with the State ofCalifornia that entitle the agency to purchase as much as 50,800 acre-feet of water per year fromthe California Water Project. The California Aqueduct delivers the water. Three turnouts forwater delivery were constructed.3.3 BIOLOGICAL RESOURCESThe California Desert Conservation Area was inventoried for its flora and fauna in thelate 1970s by the BLM Desert Plan staff. A total of 1836 vascular plant species in 116 familiesand 635 species of vertebrate animals were recorded. The West Mojave planning area was nottabulated separately, but contains a high proportion of the total. The diversity reflects the variedtopography and landforms within the planning area. Investigations of invertebrates, such asinsects, mollusks and fairy shrimp have been completed for only a few groups, but showwidespread endemism and specialization to unique substrates, host plants and water sources.Thousands of additional invertebrate species are present.The western Mojave Desert historically contained the highest densities of the deserttortoise and the only known populations of the Mohave ground squirrel, the focal species of thisHabitat Conservation Plan and CDCA Plan Amendment. It supports one of the largestpopulations of the prairie falcon. The region contains at least four endemic animals and thirteenendemic plants. A number of disjunct localities exist where plants and animals range into theplanning area far from their primary distribution.Many of the rare species of the western Mojave Desert are concentrated at special sites,where unique substrates, water sources, or topography are present. Several areas have highbiodiversity because of location at the desert-mountain transition zone. In addition, the vast openspace in much of the western Mojave Desert provides room for species to survive in the harshdesert climate.The eastern and southern Sierra Nevada Mountains extend into the West Mojave andrepresent areas of very high biodiversity. In the east Sierra canyons, riparian habitat and springsattract large numbers of nesting and migratory birds, including several target species. Thesecanyons are known to harbor rare salamanders, endemic springsnails, and a high diversity ofrodents and reptiles. The Owens Peak area stands out as a region of high endemism for plants. Inthe southern Sierras, the Middle Knob region is outstanding for its intact assemblage of predatorsand the Kelso Valley harbors endemic plants, and includes an important migratory flyway forturkey vultures, Cooper’s hawks, and Swainson’s hawks.Chapter 3 3-64