West Mojave Plan FEIR/S - Desert Managers Group

off regions discussed herein. Black Mountain is a diverse area of lava flows, with the westernportions above 20% slope, and no areas above 4,000 feet elevation. The southeastern cornercoincides with higher density areas over 6 mi 2 . Die-off regions immediately west and southeastof this area may threaten tortoises that remain.Both the Newberry and Rodman mountains wilderness areas are comprised of steepslopes (58% and 37%, respectively, occur above 20% slope), much of which is above 4,000 feet(30% and 32%, respectively). The southeastern portion of the Rodman Mountains includes 5 mi 2of higher density areas. These two areas appear to be intermediate in terms of tortoise occurrenceand conservation. Neither appears to be affected by recent die-offs, although such an area occursseveral miles west of the Newberry Mountains. There are too few data to see how the SheepholeValley may fit into the order given in the table; additional surveys in this area would be neededto determine its relative value for tortoise conservation.Although the El Paso Mountains and Golden Valley wilderness areas were relativelyunder-represented in the surveys, neither of them occurs in regions where any higher densitytortoise areas were identified. The Grass Valley Wilderness Area received more survey effortthan any other wilderness area, yet sign counts were sufficiently low throughout the area that noabove-average tortoise areas were identified. The prevalence of carcasses at Grass Valleysuggests that it was once more densely populated than at present, which does not diminish itsvalue in terms of serving as a potential head starting area. In terms of current tortoisedistribution, these three areas may provide relatively less value for tortoise conservation.Relative Overall Conservation Value of Wilderness Areas: Are wilderness areas, alone,sufficient to conserve and recover tortoises? The answer is no, for the following reasons.Wilderness areas encompass about 19 mi 2 of the 358 mi 2 (5.3%) area identified withhigher sign counts. Three of the wilderness areas (El Paso, Cleghorn Lakes, and SheepholeValley) encompass 153 mi 2 that are outside proposed DWMAs, and include 39% of allwilderness acreage in the planning area within the 2002 tortoise range. Cumulatively, wildernessareas within the range encompass 391 of 11,134 mi 2 , or 3.5% of the potentially occupied tortoisehabitat in the planning area. The 358-mi 2 area represents about 15% the size of the fourproposed DWMAs, and as given above, only 205 mi 2 (61% of wilderness areas) occurs inDWMAs, which is about 8.8% of that entire area. It would appear that the Grass Valley area hasalready been affected by die-offs within and adjacent to that region, and Black Mountain is inimminent harm’s way, assuming spread of disease from adjacent areas. Given the prevalence ofcarcasses, Grass Valley may serve as an excellent location to conduct head starting studies.De facto tortoise protection in wilderness areas relies on the assumption that there are noroads and therefore no threats to tortoises. This is a false assumption for several reasons. First,not all tortoise mortality is caused by impacts associated with dirt roads. Tortoises in wildernessareas are still susceptible to raven and feral dog predation, various diseases, and catastrophic dieoffsthat cannot be readily explained, although disease, drought, and/or synergistic effects havebeen implicated. Second, there are still known adverse human uses, even without roads. Sheepgraze the Golden Valley Wilderness Area, and vehicular trespass is considered to be a seriousproblem in places.Chapter 3 3-141