Bats of the White and Inyo Mountains of California-nevada

We surveyed bats throughout the White and Inyo Mountains of Califomia. and Nevada. From December 1990 to November 1996, we surveyed hibernating bats. and foraging bats from June 1992 to September 1996. The White-Inyo Range rests in a unique biogeographical junction between the Sierra Nevada. Mojave Desert,. and Creat Basin regions. Elevational gradients of 305-4340 m. combined with limited human development, further enhance the interest of natural history and faunal distributions in this range. We found 13 bat species in the course of 2668 observa­ tions. Three of these species. the spotted bat (EtJ.derma maculatum), silver-haired bat (Lasionycteris noctivagans), and hoary bat (Lasiuros cinereus), have DO previous records from the White-lnyo Range. We found bats in all vegetation wnes except the alpine, 3500-4342 m. Despite an abundance of mines in this range, only Townsend's big-eared bat (Corynorhinus Wwnscndii) and the western small-footed myotis (Myotis ciliolobrum) used them routinely. Our data also indicated the im~rtance of surface water to bat populations in arid regions. The White-Inyo Range rests in the junction of 3 faunal regions, the Sierra Province to the west, Mojave to the south, and Great Basin to the east. Because this range rises abruptly on its east and west sides, animals can readily access a variety of vegetation types over short linear distances. In addition to altitudinal differences, vegetation communities are enhanced by a vari­ ety of edaphic sites resulting from the range's high lithographic diversity (Elliot-Fisk 1986). Despite this interesting biogeographical setting, faunal distributions of the range have received little attention. Morrison et a1. (1993) proVided the first thorough study of bird distributions and habitat use in the White-Inyo Range. However, no systematic survey of bats and their habitat associations in these mountains has been undertaken. Hock (1963) summarized results of a handful of general collecting trips from 1917 to 1958 that yielded some bat speci­ mens. This summary plus an unpublished manuscript from a field course at University of California at Davis (Brosius et aI. ca 1974) con­ stitute all prior records. Our objectives were to provide a detailed account of bat distributions throughout the White-Inyo Range, assess how each species utilizes the different vegetation zones available to it along the range's elevational gradient, and characterize how each bat species uses avail­ able mine resources. We report observations from both foraging and hibernating bats. Because the White-Inyo Range remains rela­ tively undisturbed habitat, this baseline may prove useful for tracking long-term alterations in environment, since many researchers con­ sider bats to be sensitive indicators of environ­ mental change (Kunz 1982, McCracken 1986, Thomas 1988). These data also provide useful comparisons for other ranges in the region. Thousands of abandoned mines lie on public and private lands (Shields et al. 1995). The importance of these mines as reservoirs for wildlife displaced from natural habitats has gained increasing recognition (Tuttle and Tay­ lor 1994), and documenting patterns of mine use by bats in the White-Inyo Range may prove useful for present and future manage­ ment efforts.