Twenty-Third Annual Meeting and Symposium of the
Desert Tortoise Council, April 3-5, 1998
Abstracts

Completion of a 100% route inventory by Denver's National Applied Research Science Center (NARSC) photogrametric staff provided the foundation for designation of a vehicle route network within the West Mojave Desert portion of the California Desert Conservation Area (CDCA). The Ord Mountain Pilot Unit (126,000 acres), containing numerous sensitive resources and designated desert tortoise (Gopherus agassizii) critical habitat, was used to develop a Geographic Information System (GIS) methodology for route designation applicable to the entire West Mojave Desert.

Utilizing biological screening components routes were evaluated, coded with resource and access values, and designated "open" or "closed" based on those criteria. Critical screening components incorporated the Desert Tortoise Emphasis and Non-Emphasis Zones (DTEZs) indicative of tortoise habitat quality. Desert tortoise transect data including corrected sign, landform, elevation, and slope were correlated to determine tortoise emphasis zones rated high, medium, and low, relative to tortoise recovery value. Tortoise non-emphasis zones were identified on the basis of elevations greater than 4000 feet or landforms exceeding 30 degrees slope.

Route designation was completed by a Bureau of Land Management (BLM) interdisciplinary team providing site-specific knowledge and following management prescriptions outlined in "West Mojave Route Designation Ord Mountain Pilot Unit Biological Resource Screening Components" (BLM 1997). Concurrently, interest group representatives made route proposals on hard-copy maps containing the same data. While the Off Highway Vehicle (OHV) representatives' proposal closed few existing routes, the BLM and Desert Tortoise Council proposals were very similar. Accepted by planning partners, this GIS methodology will be expanded to the 9.2 million acres of desert encompassed by the West Mojave Coordinated Management Plan.