Landscape disturbance and sporadic hybridization complicate field identification of chipmunks

Abstract

ABSTRACTChipmunks (Tamias spp.) in western North America are important for their numerical abundance, their role in pathogen transmission, and the composition and structure of food webs. As such, land management agencies (e.g., U.S. Forest Service) often conduct field surveys to monitor the diversity and abundance of chipmunk species as a measure of forest health. These small mammal communities often include several morphologically similar chipmunk species, some of which occasionally hybridize, which can make field identification of species difficult. However, species‐specific differences in both spatial distribution and habitat use make it imperative that biotic inventories correctly identify chipmunk species. We compared molecular‐based and field‐based, external phenotypic identifications of 4 chipmunk species in the Lake Tahoe Basin of the Sierra Nevada in California and Nevada, USA. Across all years and sites, we found an error rate of 14% for field‐based identifications with significantly lower rates of misidentification in relatively undisturbed wildlands in comparison to recently burned wildlands or urbanized sites. We also found evidence for sporadic hybridization between focal species, including cases of mito‐nuclear mismatch. Our study highlights the utility of molecular tools in corroborating field identifications of chipmunks in changing landscapes. © 2016 The Wildlife Society.