Local ecological knowledge of Javan gibbon occurrence and habitat conditions in Petungkriyono, Central Java.

The Javan gibbon (Hylobates moloch), an endangered primate endemic to Java, faces significant population declines due to habitat fragmentation and degradation, particularly in the Petungkriyono Forest, an important forest landscape in Central Java. To understand the ecological and social factors that influence gibbon occurrence, we combined Local Ecological Knowledge (LEK) with ecological modelling. We conducted household surveys with semi-structured interviews with 300 respondents from three villages bordering the Petungkriyono forest. We analysed Javan gibbon occurrence data from verified LEKs, institutional records, and GBIF, and used environmental predictors derived from remote sensing. Our result shows that Javan gibbon recognition was high (96%), though the depth of knowledge and reporting of recent sightings varied by gender and education. Respondents widely perceived that the Javan gibbon was rare or declining, with recent sightings most frequently reported in Kayupuring. Ecological models indicated that gibbon occurrence was associated with multiple environmental gradients, including canopy height, vegetation density, elevation, distance to rivers, and distance from settlements, rather than a single dominant predictor. These associations likely reflect broad habitat conditions and potential variation in detectability across the mountain landscape. By integrating LEK with ecological modelling, this study provides a complementary perspective on Javan gibbon occurrence in Petungkriyono while acknowledging the limitations of both datasets. These results provide baseline information on gibbon occurrence and habitat conditions in Petungkriyono, supporting the identification of priorities for future systematic ecological assessments.