Abstract

Understanding the interplay of species-habitat relationships under anthropogenic pressure is a global imperative for the conservation of threatened biodiversity, particularly in climate-sensitive high-mountain ecosystems. The short-tailed chinchilla (Chinchilla chinchilla), an iconic and historically overexploited Andean endemic, was nearly driven to extinction due to commercial exploitation. Today, its few remaining populations persist in a tiny fraction of their historic range, often overlapping with rapid industrial development, including intense mining activities, highlighting an urgent need for management-oriented ecological data. We studied habitat relationships, activity patterns, and site-level abundance of a recently discovered short-tailed chinchilla population in the central-north Andes mountains of Chile. We used a camera trapping survey conducted between 2022 and 2023 to assess activity patterns using kernel density estimates, and integrated detection/non-detection data with biophysical variables to model occupancy and detection probabilities. The best-ranked detection-occupancy model was subsequently used to estimate the expected abundances across sites using the Royle-Nichols occupancy-abundance model. The short-tailed chinchilla was largely nocturnal, exhibiting a na & iuml;ve occupancy of 0.78, and a mean detection rate of 20.04 records/100 camera-days in the study area. Occupancy probability was influenced by thermal (solar radiation and moisture stress) and geomorphological (topographic diversity and terrain stoniness) conditions. Variation in detection probability across sites yielded an expected site-level abundance (mean +/- SE) of 2.24 +/- 0.25 individuals (min-max: 0-7). Our findings provide quantitative evidence on the importance of rocky outcrops as both structural and thermal refuges for this high-altitude specialist, while offering the first assessment of site-level abundance for the species combining non-invasive and analytical methods. This baseline for the species' local abundance and habitat requirements provides a starting point to guide management actions and to monitor new populations of this critically endangered species in the face of expanding mining activities across the Andes Mountain.