A species under siege: modelling habitat suitability for the bear cuscus <i>Ailurops ursinus</i> in South Sulawesi

Abstract Phalangerids in Sulawesi occur at the westernmost extent of marsupial distribution in Wallacea and are facing escalating anthropogenic pressures. The ecology of the Vulnerable bear cuscus Ailurops ursinus , one of four endemic phalangerids in Sulawesi, is poorly understood and the extent of its decline unknown. This study aimed to build the first habitat suitability model for the species in South Sulawesi and identify priority areas for its conservation. We used maximum entropy modelling to predict the species’ potential distribution, and overlaid the resulting habitat suitability map with regulatory and mining activity maps. Our model predicted only 7.5% (143,682 ha) of the total study area to be potentially suitable habitat for the bear cuscus, predominantly in scattered forest patches, some of which are in areas affected by active mining or frequent poaching. Land-cover type was the most important predictor of the species’ distribution. Our findings suggest the lack of legal protection for the bear cuscus should be reconsidered, and we recommend the species is reassessed for the IUCN Red List. The forested areas of southern South Sulawesi have decreased by 12.5% since 2000, with over half of this decline occurring since 2015, preventing northwards dispersal and restricting the species to a fraction of the province's protected forests. Immediate intervention is necessary to combat poaching, slow the expansion of mining and increase landscape connectivity, to prevent further reduction of the species’ current and potential habitat.