PATRICK, Lorelei E*; RUEDAS, Luis A; Portland State University; Portland State University: Multivariate morphological approaches to the ecological niche partitioning in Costa Rican bats (Mammalia: Chiroptera)

The notion of �Ecological niche� has been defined a variety of ways; one significant definition is that of a multi�dimensional hypervolume constituted by all the factors influencing an animal�s environment and behavior. This estimate of a niche may be approximated from a morphological perspective by taking a series of measurements of morphological features, thereby visualizing how animals in a community partition multivariate space. Bats are ideal organisms to study niche partitioning within a community for several reasons: Chiroptera is the second largest order of mammals (approximately 25% of all mammals are bats); they exhibit almost every feeding mode known among mammals; and many seemingly similar species are found together in the tropics. Costa Rica is an exceptional location for ecological research on bats because of its diverse habitats, extensive network of national parks, and stable government. In this study, I present my preliminary data on quantifying the ecological niches of over 30 species of Costa Rican bats using multivariate statistical analyses of 76 cranial and skeletal measurements. These measurements were taken using digital calipers from skins and skulls of specimens preserved in natural history museums. The data were analyzed using principal component analysis to visualize niche partitioning within the bat community. I predicted there little overlap among species and that all of the multivariate morphological space was optimally occupied: that is, maximal utilization of morphological multivariate niche space lead to little or no overlap among species, but high density of those species present. These ecomorphological data lead to a greater understanding of how bats use their habitat and interact at the community ecology level.