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. Kemerosotan hutan dan pemburuan adalah dua faktor utama penurunan spesies di hutan tropika. Kedua-dua ancaman ini selalu dikaitkan dengan aktiviti pembalakan dan pembangunan infrastruktur. Untuk menilai bagaimana komuniti haiwan vertebrata darat sederhana dan besar bertindak balas terhadapkedua-dua ancaman antropogenik ini, kami menjalankan survei perangkap kamera di tiga hutan simpan di pedalaman Sabah, wilayah Borneo Malaysia, masing-masing dengan rejim pembalakan yang berbeza pada masa lalu dan kini. Kami menganalisis data dari 32 spesies menggunakan model Bayesian community occupancy untuk meneliti corak occupancy, diversity dan composition terhadap kemerosotan hutan dan kebolehcapaian (sebagai proksi tekanan pemburuan). Kami mendapati bahawa kemerosotan hutan adalah pemacu kuat kepada occupancy- spesies. Respon tersebut mengakibatkan penurunan dalam diversity dan perubahan dalam composition komuniti, di mana spesies yang bergantung kepada hutan menurun sementara spesies yang lebih bertahan terhadap kemerosotan hutan meningkat dari segi occupancy. Kebolehcapaian (proksi tekanan pemburuan) menunjukkan kesan yang lebih lemah pada diversity dan occupancy. Tekanan pemburuan pada kadar yang rendah dan pengawalan akses ke lokasi survei kami berkemungkinan memainkan peranan penting dalam mitigasi kesan kobolehcapaian. Namun demikian, hasil kajian kami menunjukkan kebolehcapaian memberi kesan secara akumulatif kepada komuniti spesies yang sudah terpengaruh negatif oleh kemerosotan hutan. Meskipun ada impak kemerosotan hutan dan kebolehcapaian kepada komuniti vertebrata darat, hasil kajian kami menyoroti bagaimana pengurusan hutan yang lebih mampan seperti mengurangkan gangguan hutan dan menghadkan akses pemburu akan menghasilkan komuniti hidupan liar yang lebih utuh. Memahami bagaimana kedua-dua gangguan tersebut mengaruhi komuniti vertebrata darat secara bergabung adalah penting untuk menilai dan membangunkan garis panduan kelesterian alam yang efektif. This study examines the impact of forest degradation and hunting on the terrestrial vertebrate community in Malaysian Borneo. Using camera traps across three forest reserves, it reveals that forest degradation significantly affects species occurrence, diversity, and composition, leading to declines in forest-dependent species and increases in disturbance-tolerant ones. While hunting pressure has a weaker effect, managing access to logging roads helps mitigate its impact, emphasizing the importance of sustainable practices for maintaining intact wildlife communities.image