Trophic Niche Partitioning among Insectivorous Bats Using a Combination of Stable Isotope Analyses and Wing Morphology

Trophic dimensions of syntopic species provide information by which drivers of resource partitioning and species coexistence can be evaluated. Specialization on unique prey can minimize competition among different bat species of the same community and provide researchers and managers with insights useful for determining how resources are partitioned among species. We used stable isotope analyses of carbon (δ13C) and nitrogen (δ15N), coupled with wing morphology of bat species to estimate species-specific resource overlap and niche metrics. Isotopic ratios of δ13C and δ15N were obtained from fur of all netted bat species, which included, Eptesicus fuscus, Lasiurus borealis, Nycticeius humeralis, Corynorhinus rafinesquii, Lasiurus seminolus, and Myotis austroriparius. Results of the stable isotope analysis revealed that several species (C. rafinesquii, M. austroriparius and N. humeralis) had distinct isotopic niches but considerable overlap among others (E. fuscus, L. borealis and L. seminolus). Where stable isotope niches overlapped, morphological parameters were used to explain isotopic niche partitioning in the same habitat. The smallest isotopic niche of Corynorhinus rafinesquii indicated a small trophic niche, suggesting that this species may be more susceptible to perturbations, such as changes in prey availability and foraging habitat. Determining trophic niches of local bat assemblages will aid in better understanding resource partitioning among bat species and inform habitat managers of foraging ecology of species to guide conservation.