Changes in tropical terrestrial vertebrate communities along two anthropogenic gradients: Forest degradation and accessibility

Forest degradation and hunting are two major drivers of species declines in tropical forests, often associated with forest production activities and infrastructure. To assess how the medium-to-large bodied terrestrial vertebrate community varied across these two main gradients of anthropogenic impact, we conducted a camera-trap survey across three production forest reserves in central Sabah, Malaysian Borneo, each with different past and current logging regimes. We analyzed data from a 32-species community using a Bayesian community occupancy model, investigating the response of occurrence, diversity, and composition to forest degradation and accessibility (a proxy for hunting pressure). We found forest degradation to be a strong driver of occurrence of individual species. Such responses led to declines in diversity and shifts in community composition, where forest-dependent species decreased while disturbance-tolerant species increased in occupancy probability with increasing forest degradation. Accessibility had a weaker effect on community diversity and species occupancy, and low-level hunting pressure and management of access to our study sites likely played an important role in mitigating accessibility effects. Nonetheless, our results showed accessibility had compounding effects on a wildlife community already affected negatively by forest degradation. Despite the impacts of forest degradation and accessibility on the terrestrial vertebrate community, our results highlight how the application of more sustainable practices—reducing forest disturbance and managing unauthorized access to logging roads—resulted in more intact wildlife communities. Understanding how both disturbances combined affect the terrestrial vertebrate community is essential for evaluating and developing effective sustainability guidelines.

Abstract in malay is available with online material.