Life history, diversity and patterns of bat community structure in the Spring Mountains of southern Nevada
Abstract
This study investigated the bat community of the Spring Mountains of southern Nevada from June 1992 through September 1994. Distributions, life history and general ecological attributes of fourteen species of bats were summarized. Thirteen species were present in low to mid elevations, ten species in mid to high elevations, and three species at all elevations. Bats were most abundant in mid summer. Few differences were found among species in time of activity. The ranges of temperatures in which bats were active generally reflected their habitat use. Maximum and minimum temperatures, and weather were the abiotic factors best predicting bat activity; Relationships between local (alpha) bat diversity and local environmental variables were also investigated. Species diversity varied along an elevational gradient. Local diversity was lowest at high elevation, Pine-fir sites, and highest at low elevation, Pinon-juniper sites. Explanations for this pattern are offered based on significant correlations between bat diversity and a number of environmental variables; Changes in bat species diversity among habitats (beta diversity) were also studied. Significant differences in bat diversity were found among macrohabitats, with greater diversity at low elevation sites (Blackbrush and lower-elevation Pinion- juniper) than at higher-elevation sites (Pine-fur and higher-elevation Pinion-juniper). Because species turnover among macrohabitats was high, alpha diversity does not approximate regional (gamma) diversity, thereby illustrating that more than regional processes are involved in structuring local bat communities. Diversity changes in the Spring Mountain bat community appear to be caused by both regional and local factors, including temperature, resource conditions, and habitat heterogeneity.