Maxent modelling of habitat suitability for the endangered javan gibbon (Hylobates moloch) in less-protected Dieng Mountains, Central Java

Abstract

Dieng highland in Central Java provides high potential habitat for the endemic Javan gibbon. In order to conserve the sustainability of Javan gibbon population and its habitat in Dieng, the conservation priority for high suitable habitat should be maintained. This study aimed to identify the HSM for Javan gibbon in Dieng highland and the most contributing biophysical variables. Medium-resolution variable layers, which interpret the biophysical environment of gibbon habitat, were derived and pre-processed from Sentinel-2 image and Indonesian elevation model product. A total of 305 occurrence data recorded in extensive field survey non-correlated 11 variables were maintained for HSM in presence-only machine learning, maximum entropy (MaxEnt). Suitable gibbon habitats were predicted as 81.286 km2. The area under the curve value estimated to be 0.971 and 83.516 % of validating points was on suitable habitat. The final model pointed out that the suitable areas were fragmented. Relatively large of the suitable patch for Javan gibbon located in Sokokembang, Linggoasri-Mendolo, and western of Kembanglangit were considerable to get the conservation priority. The most contributed variables were a natural forest, elevation, distance to cropland and land surface temperature, which are important factors to be considered when generating a conservation strategy for Javan gibbon.