Ecology and management of bats in pinyon-juniper woodlands of west-central New Mexico

Pinyon juniper woodlands are a widely distributed vegetation type that have a markedly different structure than most western coniferous forests in which bats have been studied. The objectives of this study were to evaluate the use of pinyon juniper woodlands by bats, to characterize day roosts of reproductive females of 3 species, to compare patterns of roost use and behavior among species, and to examine long-term use of trees by colonies. To evaluate relative use, I compared species richness, relative abundance, and reproductive status of bats in pinyon juniper woodlands with those in ponderosa pine forest, an adjacent vegetation type. More species were identified in pinyon juniper woodlands than in ponderosa pine forest, but overall capture rates were similar. High ratios between reproductive and nonreproductive female capture rates suggest that a greater proportion of females were reproductively active in pinyon juniper woodland.; To characterize roost use, I radiotracked 58 reproductive females of 3 species (Myotis evotis, M. volans, and M. thysanodes ) to 109 day roosts in pinyon (Pines edulis), juniper (Juniperus monosperma and J. deppeana ), and ponderosa pine (P. ponderosa). Characteristics of roost trees varied with tree species. In junipers, bats roosted in crevices and natural cavities of part-live, part-dead trees. In pinyons, bats roosted under bark of snags in early stages of decay. In ponderosa pine, colonies roosted in large, vertical cracks in the trunk. Differences among bat species in patterns of roost use and behavior suggest that roost resources were partitioned among bat species.; To examine long-term reuse of roosts, 15 colony roost trees were monitored with exit counts every 2–4 weeks for 2–4 summers. Colony roost trees were reused most of the summers they were monitored, suggesting that bats have a greater long-term fidelity to trees than expected. However, colonies used trees intermittently within-summer, making their presence difficult to detect with periodic exit counts.; Pinyon-juniper woodlands support diverse and abundant bat communities and provide valuable summer roost habitat for reproductive female M. evotis, M. volans, and M. thysanodes. Fuelwood harvesting may have negative impacts on bat habitat because large, recently dead and dying trees are often preferred.