DESERT TORTOISE & LANE MOUNTAIN MILKVETCH
Distributions in the Proposed Expansion Area for
Fort Irwin National Training Center
I. Expansion Area.
The western expansion area is the Superior Valley, designated critical habitat for the desert tortoise and home to the endangered Lane Mountain Milkvetch. The cross hatching on the south end of Fort Irwin is the UTM 90 area which is designated critical habitat that is currently managed for the benefit of its large tortoise population but would be opened to maneuvers under the expansion legislation.
II. Desert Tortoise
This map of tortoise sign distributions was generated by the West Mojave planning team. Note the large band of sign in the UTM 90 lands at the south end of the base and the sign density in the Superior Valley where tanks exercises will be held. In addition, the proposed expansion will increase habitat fragmentation and effectively isolate the tortoise population on the Naval base to the north.
III. Lane Mountain Milkvetch.
Only three populations of the Lane Mountain Milkvetch (Astragalus jaegerianus) are known. The largest and most viable populations are found in the western expansion area. The only population outside this expansion area consists of highly at risk plants located near human settlements at Coolgardie Mesa.