Camera trap surveys reveal hidden mammalian diversity in rocky outcrops from southeastern Peruvian highlands

Rocky outcrops are conspicuous formations in the southeastern Peruvian highlands, providing shelter to several species that inhabit habitats with harsh conditions above 3,500m. Despite their ecological importance for species survival, mammalian diversity remains poorly documented in the Peruvian Altiplano. Between January 2012 and December 2022, we used camera traps to survey 7 localities in the Altiplano of the Departments of Moquegua, Puno, and Tacna gathering a total sampling effort of 15,946 camera-days. We recorded 14 native and 1 exotic mammal species (Lepus europaeus). Rodents dominated the community, with Abrocoma cinerea, Lagidium viscacia, and Abrothrix jelskii comprising 75% of total detections. Seasonal patterns were evident with A. jelskii and L. viscacia increasing their capture frequency index (CF) in the dry season, while A. cinerea remained dominant and the most frequently captured species across seasons. Alpha diversity analyses revealed similar species richness between seasons, though diversity of common and dominant species was higher in the dry season. Beta diversity comparisons showed moderate to high similarity among Peruvian rocky outcrops, but lower similarity between distant rocky outcrops (Argentina vs Peru) and between rocky outcrops and open habitats, suggesting species turnover. This study provides the first mammalian inventory in Peruvian rocky outcrops using camera traps, covering one of the highest altitudinal ranges in the region. We discuss seasonal trends in species CF and diversity, reinforcing the role of rocky outcrops as refugia. Finally, we highlight the importance of camera traps for biodiversity monitoring in highland habitats, the potential impact of exotic species, and the urgent need for further research on these threatened habitats.