Where and How Are Roads Endangering Mammals in Southeast Asia's Forests?

Habitat destruction and overhunting are two major drivers of mammal population declines and extinctions in tropical forests. The construction of roads can be a catalyst for these two threats. In Southeast Asia, the impacts of roads on mammals have not been well-documented at a regional scale. Before evidence-based conservation strategies can be developed to minimize the threat of roads to endangered mammals within this region, we first need to locate where and how roads are contributing to the conversion of their habitats and illegal hunting in each country. We interviewed 36 experts involved in mammal research from seven Southeast Asian countries to identify roads that are contributing the most, in their opinion, to habitat conversion and illegal hunting. Our experts highlighted 16 existing and eight planned roads - these potentially threaten 21% of the 117 endangered terrestrial mammals in those countries. Apart from gathering qualitative evidence from the literature to assess their claims, we demonstrate how species-distribution models, satellite imagery and animal-sign surveys can be used to provide quantitative evidence of roads causing impacts by (1) cutting through habitats where endangered mammals are likely to occur, (2) intensifying forest conversion, and (3) contributing to illegal hunting and wildlife trade. To our knowledge, ours is the first study to identify specific roads threatening endangered mammals in Southeast Asia. Further through highlighting the impacts of roads, we propose 10 measures to limit road impacts in the region.

栖息地破坏与过度捕猎是热带森林哺乳动物种群下降及物种灭绝的两大核心驱动因素，道路建设往往会成为这两类威胁的催化剂。当前在东南亚区域尺度上，道路对哺乳动物的影响尚未得到充分记录与研究。在制定基于证据的保护策略以最小化该区域道路对濒危哺乳动物的威胁之前，我们首先需要明确各国境内道路在哪些维度、以何种方式加剧了栖息地破坏与非法捕猎活动。为此，我们采访了来自东南亚7个国家的36位哺乳动物研究领域专家，以识别出他们认为对栖息地破坏和非法捕猎贡献最大的道路。专家们共提名16条已建成道路与8条规划道路——这些道路可能威胁到上述国家117种濒危陆生哺乳动物中的21%。除了收集文献中的定性证据以佐证专家们的判断外，我们还展示了如何通过物种分布模型、卫星影像与动物痕迹调查，从三个维度量化道路造成的生态影响：（1）穿越濒危哺乳动物的潜在栖息地带；（2）加剧森林开垦活动；（3）推动非法捕猎与野生动物贸易。据我们所知，本研究是首个在东南亚范围内明确具体威胁濒危哺乳动物的道路的研究。此外，通过梳理道路带来的各类负面影响，我们提出了10项可用于限制该区域道路生态危害的保护措施。