| Little is known about the dynamics of roost use by Townsend's big-eared bat (Corynorhinus townsendii). In Chapter 2, I investigated the response of C. townsendii to the dramatic alteration of the roosting landscape resultant from underground mining and human settlement in the western United States. In investigating specific response, I tested the hypothesis that this species is a Pleistocene relict, as proposed by Humphrey and Kunz (1976). I found that C. townsendii remains an obligate of subterranean habitat, throughout the Great Basin with patterns of use consistent with the relictual status of this species.; In Chapter 3, I investigated patterns of roost use and fidelity of colonies of C. townsendii. I discovered that both roost selection and patterns of roost use are spatially and temporally variable, with colonies exhibiting higher proportions of use and greater fidelity to caves than abandoned mines. In areas in which complex subterranean habitat was available, selection of roosts was most strongly associated with variables describing subterranean conditions. In landscapes dominated by simple subterranean habitat, selection of roosts was most strongly associated with surface associations. In addition, colonies using larger, more complex mines exhibited greater levels of fidelity than those using more simple workings.; In Chapter 4, I investigated the hypothesis that the presence of warm roosts in the landscapes functions as a local constraint to the presence of maternity colonies of this species. I found that maternity colonies were capable of manipulating roosting temperatures. However, the number of individuals in the colony dramatically affected the amount of temperature manipulation. While smaller colonies did raise roosting temperatures, these increases were not sufficient to compensate for cool background temperatures, and these colonies remained reliant on finding the warmest portions of the warmest subterranean habitat available. However, metabolic heat produced by larger colonies of C. townsendii appeared to buffer them from background temperatures to such a degree that they were located independently of temperature as measured in this study. |
