West Mojave Plan FEIR/S - Desert Managers Group

Population Status in the Planning Area: The western Mojave Desert comprises themajority of the range of alkali mariposa lily, although the Kern River Valley east of LakeIsabella supports substantial populations. Within the Planning area are some very significantpopulations as well as smaller, scattered populations. Large numbers of alkali mariposa lilies areknown from Edwards AFB (>100,000 plants), Los Angeles County just south of the southwestcorner of Edwards AFB (10,000 plants), and Paradise Spring near Fort Irwin (2-3,000 plants).The Kelso Valley contains alkaline meadows supporting >2,000 plants in 1988. This area is asouthern extension of the Lake Isabella group of occurrences.Smaller populations of this species are known from Red Rock Canyon State Park andCushenbury Springs. Collections have been recorded from several playas and alkaline springsbetween EAFB and Fort Irwin, and one outlying population was recorded from TwentyninePalms in 1902. Many playas within the planning area have not been surveyed for this species.Regulatory Status: California Species of Special Concern.Threats Affecting the Alkali Mariposa Lily: Many occurrences are threatened withurbanization, especially the very large populations in the Amargosa Creek floodplain nearLancaster. Reduction of water supply to playas and alkaline floodplains could pose a threat.Maintenance of sheet flooding in the Rosamond Lake basin is essential, and the west part of thisbasin is becoming fragmented by agriculture and urban development. Lowering of groundwaterto alkaline springs and seeps is a potential threat. The next greatest threat is urbanization in theLancaster area where the largest populations are concentrated.Grazing is a potential threat to the plants on private ranch lands in the Kelso Valley.3.3.8.2 Barstow Woolly SunflowerLife History: This species is a western Mojave Desert endemic. It is found on bareareas with little soil, often containing a shallow subsurface caliche layer.Population Status in the Planning Area: Most known locations are between KramerJunction and Harper Dry Lake. The range of Barstow woolly sunflower, however, extends westof Kramer Junction and includes Edwards Air Force Base. It is also located east of Harper DryLake on the Coolgardie Mesa. The BLM has established a 320-acre ACEC for protection of thisspecies east of Kramer Junction. CDFG mitigation lands northeast of Kramer Junction arebelieved to support this species.Regulatory Status: BLM Sensitive.Threats Affecting the Barstow Woolly Sunflower: Populations are subject to removalwithin the utility corridor between Kramer Junction and Harper Dry Lake. Military operations atEdwards AFB could be a threat in the future. Current management at EAFB is compatible withprotection of this species. Off-road vehicle travel is a threat.Chapter 3 3-185