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.