West Mojave Plan FEIR/S - Desert Managers Group

juvenile male MGS on a dirt road as it attempted to cross in front of his truck. In 1997, LaRueobserved a juvenile male (likely a hybrid) as it was crushed on National Trails Highway, severalmiles north of Helendale. One of the nine MGS observed in 1998 (LaRue, unpublished data)darted into burrows that were located in the berms of a dirt road. The juvenile female wasobserved for about 20 minutes eating cryptantha alongside the road, and later using two differentburrows located in berms on opposite sides of the road. Recht (1977) also observed MGSfeeding on Russian thistle that was congregated along shoulders of roads in northeastern LosAngeles County.Goodlett and Goodlett (1991) have shown, in the Rand Mountains, that the heaviestvehicle impacts occur immediately adjacent to both open and closed routes. It is plausible, then,that individual MGS using resources adjacent to roads are more likely to be in harm’s way thanthose animals occurring in roadless areas. It is also plausible that juvenile MGS, which are mostlikely to travel longer distances than adults, are somewhat more susceptible to vehicle impactsthan adults. Although adults may still be susceptible to vehicle impacts within their somewhatfixedhome ranges, dispersing juveniles are likely to encounter more roads than an adult livingwithin a fixed region.The potential to crush squirrels likely increases as the prevalence and use of roadsincreases in a given region. Given the relatively higher incidence of cross-country travel in openareas (1998-2001 WMP data), vehicle impacts are more likely to occur there and other placeswith similar densities of cross-country tracks, depending on resident and dispersing populationsof the MGS. This would suggest that there may be relatively more impacts in the Spangler Hills,Jawbone Canyon, Dove Springs and El Mirage open areas, which occur within the range, butdoes not negate the possibility that impacts may also be prevalent in heavy OHV use areas, suchas occur in the vicinity of “Camp C” near the western end of the Rand Mountains.In Table 3-36, incidences of six vehicle-based disturbances observed between 1998 and2002 are compared between designated open areas and one heavy use area, between CaliforniaCity and the Rand Mountains. The first table lists data for trails, tracks, and litter; followed bytargets, hunting, and camping in the second table.The tables document the types of heaviest vehicle-based impacts observed within therange of the MGS in three open areas (excluding Olancha, which was not surveyed) and onehevy OHV use area. All vehicle-based impacts in these areas were above average, as describedin the tortoise section. The data include vehicle impacts both inside and outside the open areas,the latter of which are clearly associated with the vehicle impacts emanating from open areas(see Map 3-14).One can see that the Spangler Hills Open Area had the highest incidences of trails(19.3/mi 2 compared to 16.9/mi 2 at the next highest incidence at El Mirage), litter (39.1/mi 2compared to 21.0/mi 2 at El Mirage), and target shooting (18.0/mi 2 compared to 17.6 at JawboneCanyon/Dove Springs). El Mirage had the highest incidence of cross-country vehicle tracks (at120.7/mi 2 compared to Spangler Hills at 95.6/mi 2 ) and hunting areas (2.3/mi 2 compared to1.5/mi 2 in the heavy OHV use area).Chapter 3 3-162