Predicting indirect effects of transportation network expansion on Asian elephants: Implications for environmental impact assessments

The rapid proliferation of transportation networks (TNs) threatens the viability of species with wide geographic ranges via habitat fragmentation, road kill, and indirect socio‐ecological interactions. Environmental impact assessments of TNs are mostly descriptive and focus on the direct impacts of the linear features of TNs, while the indirect and cumulative impacts are largely neglected. Using spatially explicit data of elephant‐caused damage from 2012 to 2015 in southwest China, we quantified the barrier effects of TNs on Asian elephant populations and predicted future patterns of damage under a TN expansion scenario using maximum entropy algorithms. The TNs acted as a strong barrier for the elephants, even in herds that have inhabited highly fragmented landscapes for years. Overall damage patterns were highly asymmetric around roads, with only 18% of events occurring on the far side of roads (relative to the core home range). Models predicted that TN expansion would reduce elephant habitats, exacerbating herd isolation and human–elephant conflict locally. Thus, we suggest that future environmental impact assessments should integrate mitigation of indirect conflicts. in Chinese is available with online material. 摘要 由于侵占栖息地、路杀、增加与人的负面接触, 快速扩张的道路网威胁着野生动物的生存繁衍, 家域大的动物受到的威胁尤甚。然而, 在环境影响评价中, 道路建设对野生动物影响的评估通常是描述性的, 且仅针对道路本身, 对野生动物的间接和累积影响常常被忽视。利用2012年至2015年中国亚洲象的肇事数据和最大熵模型, 本研究尝试量化道路对亚洲象的阻隔作用和预测道路扩张对亚洲象分布的影响。研究发现: 主要道路对于在斑块化景观中栖息多年的亚洲象来说, 仍是强烈的阻碍, 仅18%的肇事事件发生在道路的另一侧; 道路网扩张将进一步压缩亚洲象的栖息地, 加剧象群间的阻隔和局部人与亚洲象冲突。因此我们建议在未来的环境评价中应该充分考虑道路建设对人与亚洲象冲突的影响, 并制定缓解措施。