Brian L. Cypher; CSU-Stanislaus, Endangered Species Recovery; One University Circle, Turlock, CA, 95382; (661) 835-7810; bcypher@esrp.csustan.edu; Scott Phillips, Tory Westall, Erin Tennant, Larry Saslaw, Erica Kelly, Christine Van Horn Job
Tipton kangaroo rats (Dipodomys nitratoides nitratoides: TKR) once were widely distributed in arid scrub habitats in the southern San Joaquin Valley. Much of this habitat has been destroyed and remaining habitat is limited to small fragments. We conducted surveys by live-trapping on 44 sites and detected TKR on 15 sites. Sites with TKR had larger alkali scalds and no obvious sign of past tilling compared to sites without TKR. Also, sites with TKR usually had sparse ground cover and seepweed was present. Finally, a larger competitor, Heermann's kangaroo rat (D. heermanni), was either absent or present in relatively low numbers at sites with TKR, and abundance was inversely related with that of TKR. An estimated 30,000 ha of moderate-high quality habitat and 60,000 ha of lower quality habitat remain. However, habitat is still being lost and we documented conversion of several sites with TKR. Furthermore, TKR were extirpated on several other sites due to catastrophic events and changes in habitat management. Thus, this species is still in rapid decline and remaining populations are at high risk of extirpation. Enhanced conservation efforts are warranted to avoid extinction, as may have befallen the closely related Fresno kangaroo rat (D. n. exilis).
The Anthropocene: Decline & Extinction II