By Kurnia Latifiana
Updating land cover information and habitat suitability assessments provide a baseline for identifying priority areas for protection, restoration, and improved management. The maps produced through this assessment can thus support in considering conservation decision making across Mentawai Islands. By providing insight and a comprehensive spatial perspective as an effort to strengthen primate conservation strategies and contribute to evidence based actions that safeguarding Kloss’s gibbon and their remaining forest habitat.
Objectives
To contribute insight of conservation actions for Kloss’s gibbon, this assessment aims to:
- Update the land cover map of Mentawai Islands to provide current representation of forest condition and potential threats in the landscape
- Develop and estimate suitable habitat for Kloss’s gibbon across the islands using spatial and ecological variables to identify priority habitats and areas potential at risk
Methods
Our study took place across the Mentawai Islands, focusing especially on nine customary forests in Madobag and Matotonan villages. These forests are cared for by local communities, and they are very important because they provide homes for Kloss’s gibbons and help keep the forest connected. To understand how well these areas support gibbons, we combined knowledge from past studies with new observations from the field. We looked at where gibbons were seen, and we also noted the condition of the land and forest. Using satellite images, we created updated maps of forest cover, which we checked and refined with help from local surveys. Finally, we used a computer model to predict which areas are most suitable for gibbons, considering factors like forest cover, tree health, land shape, climate, and how close the forest is to rivers or villages. This way, we can see which places are most important for protecting gibbons and supporting community efforts to keep the forest healthy.
Results
Land cover mapping
Kloss’s gibbons are strongly associated with forested habitats, particularly secondary forests.The updated land cover map of 2025 provides a current spatial overview of forest conditions across the Mentawai Islands, with particular attention to nine customary forests in Madobag and Matotonan villages. Land cover classification has limitation in distinguishing between secondary forest and mixed planted trees vegetation. Field verification helped improve classification accuracy, particularly in areas dominated by mixed vegetation zones and small patches of secondary forest.
Habitat suitability assessment
The predicted suitable habitat spatially overlapped with the majority of gibbon occurrence records from previous studies and recent field survey in 2025. There are 60 presence points (95%) fall within areas classified as suitable habitat, indicating agreement between model prediction and field observation.
Across the Mentawai Islands, suitable habitat was estimated at around 399,045.24 ha and representing 66.69% of the total area (see Table ), which 302,647.59 ha area is in Siberut Island. Within priority customary forests on Siberut Island, suitable habitat was predicted to cover approximately 78.59% of the island. Suitable habitat area by island is summarized in the table.
Habitat suitability was shaped by a combination pattern of forest structure, climatic conditions, and terrain characteristics. As shown in Figure 2, land cover was the most influential variable, contributing 40% to the model, followed by precipitation (22%), tree cover (18%), and elevation (14%), while all remaining variables individually contributed less than 10%. Human pressure variables showed relatively low direct contributions, not because they are ecologically insignificant, but because their effects are largely captured indirectly through land cover changes and forest condition.
The model confirmed that the secondary forest is the most critical predictor of Kloss’s gibbon distribution in Mentawai Islands. Areas with higher tree cover were associated with a higher probability of gibbon occurrence. This condition also confirmed the gibbons are strong dependence on structurally intact forest canopies. Kloss’s gibbons depend on upper canopy layers for key behaviors, including locomotion, feeding, resting, and vocalization, which require continuous and well developed forest structure.
Disclaimer :The information displayed here is only some part of the habitat suitability analysis for the Mentawai Gibbon Conservation Program, please please contact swaraOwa @gmail.com, for further discussion of the analysis.