West Mojave Plan FEIR/S - Desert Managers Group

There were no MGS occurrences in 28 of the 44 plant communities occurring within theplanning area. When combined, however, these 28 plant communities comprise only 7.4% of theplanning area, and are generally outside the known range. Three of the 28 plant communities, whichcomprise 4.2% of the 7.4%, are either not habitat (Playa at 1.7%) or mostly occur above theelevation range of the MGS (Semi-Desert Chaparral at 1.4% and Mojavean Pinion JuniperWoodland at 1.1%).The analysis also provides one means of measuring the relative impact of urbanization andagricultural development on historically occupied habitats. Recall that the data have been collectedsince 1886, and the “vegetation communities” given above were derived in 1996. Therefore, thecommunities include both native plant communities and type-converted communities (i.e., nativehabitats that have recently been replaced by manmade communities). As such, Urban communitiescurrently occupy about 6% and Agriculture communities occupy about 4% of the historical MGSrange. Excepting a few anecdotal accounts of MGS in such areas (see below), these data suggestthat about 10% of the native habitat has been converted to urban and agricultural uses, which areultimately not suitable for the species (Laabs 1998).3.3.3.5 ThreatsThis section provides a general discussion of threats and impacts that have been given inthe literature, and includes recent data for comparison. Except for the first section, whichdescribes human disturbances observed during the 1998 survey, the threats are presented inalphabetical order (as opposed to severity or importance of a given threat).Human Disturbances Observed During 1998 Vegetation Studies: During the 1998survey, biologists collected information on human disturbances observed along each of 310transects, including those located near previous MGS reports (102 transects) and those located inhigh and medium quality habitats (208 transects). Table 3-35 indicates the prevalence ofdisturbance types found along these transects 30 .30 "OHV” refers to cross-country vehicle tracks, which were created by trucks, motorcycles, and all-terrainvehicles. “Road” includes trails, and usually included routes passable by trucks. Sheep, cow, and dog sign wereusually feces. “Guns” does not differentiate between legal activities (e.g., hunting, regulated target practice, etc.)and illegal ones (e.g., shooting glass and articles at dump sites). “Dumps” generally required a vehicle to off-loadthe materials, so does not include litter. “Mines” may have included pits and adits, exploratory excavations, borrowpits, etc. “Ord” refers to military ordnance, which typically included spent cartridges and clips from aircraft. Twotransects occurred in areas previously burned. Most of the transects (237 of 310, 76%) were surveyed by LaRue, sosubjective determinations among surveyors is not considered a significant problem.Chapter 3 3-157