West Mojave Plan FEIR/S - Desert Managers Group

aseline data are lacking. Grasses provide much lower quantities of protein than do forbs (Nagyet al 1998, Hazard et al. 2001), and may be relatively more abundant in habitats degraded bygrazing, fire, and other ground disturbances.These weeds in turn serve as fuel for wildfires. Lovich and Bainbridge (1999) reportedthat exotic annual plants, particularly red brome (Brooks 1998, Oldemeyer 1994), increase thefuel load and frequency of fire in desert communities, which are poorly adapted to fire. Redbrome, split grass, Russian thistle, and mustards (particularly in fallow agricultural fields)provide fuels that burn hotter and carry flames between shrubs, thereby promoting the spread offire and relatively more damage to native shrubs. (Brown & Minnich 1986; Brooks 1999.)Minnich (1994) reported that flames are carried by exotic species, notably Bromus rubens,Schismus barbatus, and Brassica tournefortii, which form a continuous, cured layer of flashyfuels; and that the greatest short-term impact of desert fires is the destruction of Larreatridentata (creosote bush).Ravens represent a direct impact to juvenile tortoise populations, but they are also anindirect impact (or symptom) of urbanization. Ravens are as common as they are because ofincreased opportunities provided by humans. Roads provide a ready source of raven food in thecarcasses of small mammals and reptiles that result from vehicle collisions; increased nestingopportunities are provided by human structures; water is readily available at pastures, farmlands,sewage ponds, and wildlife guzzlers. Yet, ravens are often identified as “natural” predators oftortoises. In fact, ravens are subsidized predators, possibly preying on tortoises and otheranimals to get them through the summer and winter when resources are less plentiful (Boarman1993).The denuded hillsides that result from OHV hill climbs are extremely susceptible toerosion (indirect mortality factor), particularly if mechanized vehicles continue to frequent thearea (a direct mortality factor). Both forage and shrub cover, which are critical to tortoisenutrition and denning, respectively, are adversely affected. In time, tortoises may abandon thearea or suffer ill side effects from poor nutrition (i.e., malnourished, suppressed immune systems,etc.) or reduced denning potential (i.e., resulting in more exposure to predators and additionalvehicle impacts).Indirect mortality factors may occur far into the future and are often unforeseen. Forexample, the direct impact of a water pipeline is immediately mitigated and compensated,tortoises are moved from harm’s way with appropriate take permits, and the project is effectivelycomplete, but the indirect effects are just beginning. Dozens of residents each year excavatetheir own ancillary pipeline trenches to connect into the main water line; these go unmonitoredand tortoise protection is relegated to whoever is digging the trench. Such projects are theinfrastructure that is intended to promote human population growth that will eventually eliminateanimals from those regions. Mechanically denuded rights-of-way are often used for vehicletravel and may provide new access to tortoise populations that were not previously accessible tonon-four-wheel drive vehicles. This was the case for extensive stretches of the Meade-Adelantotransmission line that was installed in 1995. Not only were 174 tortoises handled and 3accidentally killed (LaRue 1996), but the line passed through areas where no previous utilitieshad passed, thereby opening new access to many areas.Chapter 3 3-101