Roost Sites of Allen's Lappet-Browed Bats (Idionycteris Phyllotis) (Notes) (Report‪)‬

Allen's lappet-browed bat (Idionycteris phyllotis) is among the rarest bats in North America (Western Bat Working Group, http://wbwg.org/species_accounts/vespertilonidae/idph.pdf). It occurs from central Mexico northward through the southwestern United States, including Arizona, New Mexico, southern Nevada, and southern Utah (Adams, 2003). Recorded locations range from the Mojave Desert to fir (Abies) forest at elevations of 403-3,225 m, but most have been reported from elevations of 1,100-2,500 min oak-juniper (Quercus-Juniperus) woodland and ponderosa pine (Pinus ponderosa) forest (Brown et al., 2005). The study area was in the Grand Staircase province of the Colorado Plateau physiographic region within Grand Staircase-Escalante National Monument, Kane and Garfield counties, Utah. This region is characterized by highly erodible sandstones typical of the desert Southwest. General physiography is a series of large plateaus and valleys dissected by numerous deep, steep-sided canyons and ravines. The Grand Staircase province is 229,655 ha at elevations of 1,413-2,625 m, and temperatures often are 38[degrees]C in summer. Within the study area, 16 species of bats are known (K. S. Day and L. C. Peterson, in litt.). Desert-shrub communities (Artemisia, Chrysothamnus, Rhus trilobata) predominate at lower elevations, and much of this landscape is barren. Plant communities transition to pinon (Pinus edulis) and juniper at middle elevations and ponderosa pine, spruce (Picea), and fir at the highest elevations and latitudes. Annual rainfall is 26 cm, which frequently falls in summer torrents that cause flash floods and considerable erosion. Riparian habitats are limited and tend to be ephemeral, but provide the greatest diversity of vegetation. These areas support cottonwood (Populus), willow (Salix), ash (Fraxinus), and boxelder (Acer negundo), but also the invasive salt cedar (Tamarix). The study area is at the far northern reach of, if not outside, the range for I. phyllotis (Bat Conservation International, http://batcon.org/SPprofiles/detail.asp?articleID=99).