Data from: Widespread forest vertebrate extinctions induced by a mega hydroelectric dam in lowland Amazonia

Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments.

全球范围内，热带森林中的大型水电工程（mega hydropower projects）对陆地与淡水生物多样性构成了新兴的重大威胁。尽管低地热带森林（lowland tropical forests）中已建、在建及规划中的水电大坝（hydroelectric dams）数量空前，但相关研究尚未评估其对生物多样性造成的长期影响。我们以亚马孙中部（Central Amazonia）某大型水电水库为研究对象，探究了陆地与树栖脊椎动物（arboreal vertebrates）的中大体型物种类群——涵盖35种哺乳类、鸟类及陆龟类——如何响应该水库蓄水隔离26年来的剧烈群岛化景观结构改变与生境质量退化历程。巴尔比纳水电站大坝（Balbina Hydroelectric Dam）淹没了3129平方千米的原生林，同时割裂出3546座陆桥岛屿（land-bridge islands）。我们结合四种调查方法，对其中37座岛屿及周边3片连续森林开展了高强度生物多样性普查，结果发现显著的森林生境面积效应可有效解释脊椎动物灭绝的分布格局。除明确的面积效应外，边缘介导的地表火干扰是造成物种丧失的另一关键驱动因子，尤其在面积小于10公顷的岛屿中表现更为突出。基于种-面积模型（species-area models），我们预测当前仅0.7%的岛屿仍拥有物种丰富的脊椎动物类群，其物种丰度可达全部调研物种的80%及以上。本研究揭示了人工大坝引发的脊椎动物多样性大幅丧失，并表明低地热带森林区域内大型水坝的生物多样性影响长期被严重忽视。在低地亚马孙等区域推广更多大型水电基础设施项目的地缘政治战略亟需重新评估，我们强烈建议将生物多样性的长期影响明确纳入项目审批前的环境影响评价（environmental impact assessments）流程中。