Denisse Mateo Chero, Fernando Hancco Pacha, Megan Owen, Mathias Tobler

Decisions for the conservation of Andean bears (Tremarctos ornatus) must currently be based on limited empirical knowledge of the species' biology, and extrapolation from what is known about other bear species, none of which are closely related to Andean bears. We sought to improve our understanding of this bear's distribution and habitat use in the Manu Biosphere Reserve of SE Peru, a biodiversity hotspot that is considered to be a core conservation area for the species. Direct human impact in this landscape is primarily restricted to well-defined portions of the landscape. We installed 283 unbaited camera trap stations along an elevational gradient from 275 masl (below expected bear occurrence) to 3580 masl (tree-line). Although Andean bears use food resources in nearby alpine grasslands seasonally, the seasonality of bear habitat use inside these highly diverse tropical forests is unknown. We therefore operated cameras continually from 2016-2021. We then used a multi-species dynamic Royle-Nichols occupancy model to look at the distribution of Andean bear and 21 other terrestrial mammal species across elevations. We obtained 546 independent detections of Andean bears from 811 to 3692 masl. Bear occupancy increases with elevation from 0.09 at 1000 m to 0.82 at 3500 m. In this landscape, many abiotic and biotic variables are associated with elevation, so teasing out the drivers of bear occupancy will require further analyses. Understanding occupancy of Andean bears in this important landscape will, in turn, help guide conservation planning in similar landscapes nearby, including in proposed conservation corridors.