Ecological factors associated with site occupancy of an endemic chipmunk

Abstract

ABSTRACTThe Oscura Mountains Colorado chipmunk (Neotamias quadrivittatus oscuraensis) is a rare subspecies of the Colorado chipmunk that is listed as threatened by the state of New Mexico, primarily because it is an endemic subspecies with a small, isolated habitat and the potential for continuing habitat loss. Knowledge about its ecology is limited, which has hindered the development of scientifically defensible management plans. Our goal was to better understand the ecological factors related to the distribution and habitat selection of this chipmunk. We deployed baited camera traps in the Oscura Mountains, New Mexico, USA, using an occupancy modeling framework to determine which ecological factors are associated with occupancy and detection probability. We collected microhabitat and landscape‐level data for use as covariates in the occupancy models. We detected the Oscura Mountains chipmunk at 26 of the 137 survey sites. Occupancy probability was not influenced by the microhabitat characteristics measured and the final model contained only landscape‐level covariates on occupancy. Probability of occupancy was positively associated with proximity to an escarpment, two‐needle pinyon (Pinus edulis) woodland vegetation community type, and elevation. Detection probability was positively associated with the presence of mature two‐needle pinyons at the site. Habitat loss is a major concern for this taxon, especially because climate change is expected to exacerbate threats to pinyon woodlands. Drought, wildfire, bark beetle (Ips confusus) outbreaks, and other diseases pose a large risk to conifer woodlands throughout the southwestern United States. Conserving the pinyon woodlands on the Oscura Mountains, particularly in areas near escarpments, will help maintain habitat that is important for the Oscura Mountains chipmunk. © 2018 The Wildlife Society.