Forest edges influence more than half of the world’s forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1,673 vertebrate species. We show that the abundances of 85% of species are affected, either positively or negatively, by forest edges. Species that live in the centre of the forest (forest core), that were more likely to be listed as threatened by the International Union for Conservation of Nature (IUCN), reached peak abundances only at sites farther than 200–400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest-core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale.

Cost-effective conservation on private land: How affordable is biodiversity conservation in a fragmented landscape? Banks-Leite et al. asked this question for the biodiversity hotspot of the Brazilian Atlantic Forest. An annual investment of <10% of Brazil's agricultural subsidies could support effective ecological restoration on private lands. This would increase biodiversity in set-aside land to the same level observed in protected areas. The cost-effectiveness of this scheme suggests a path forward for conservation strategies in other similarly mixed landscapes, too. Science , this issue p. 1041

Tropical forest species are among the most sensitive to changing climatic conditions, and the forest they inhabit helps to buffer their microclimate from the variable climatic conditions outside the forest. However, habitat fragmentation and edge effects exposes vegetation to outside microclimatic conditions, thereby reducing the ability of the forest to buffer climatic variation. In this paper, we ask what proportion of forest in a fragmented ecosystem is impacted by altered microclimate conditions driven by edge effects, and extrapolate these results to the whole Atlantic Forest biome, one of the most disturbed biodiversity hotspots. To address these questions, we collected above and below ground temperature for a full year using temperature sensors placed in forest fragments of different sizes, and at different distances from the forest edge. In the Atlantic forests of Brazil, we found that the buffering effect of forests reduced maximum outside temperatures by one third or more at ground level within a forest, with the buffering effect being stronger below-ground than one metre above-ground. The temperature buffering effect of forests was, however, reduced near forest edges with the edge effect extending up to 20 m inside the forest. The heavily fragmented nature of the Brazilian Atlantic forest means that 12% of the remaining biome experiences altered microclimate conditions. Our results add further information about the extent of edge effects in the Atlantic Forest, and we suggest that maintaining a low perimeter-to-area ratio may be a judicious method for minimizing the amount of forest area that experiences altered microclimatic conditions in this ecosystem.

Vulnerability to habitat fragmentation: Habitat fragmentation caused by human activities has consequences for the distribution and movement of organisms. Betts et al. present a global analysis of how exposure to habitat fragmentation affects the composition of ecological communities (see the Perspective by Hargreaves). In a dataset consisting of 4489 animal species, regions that historically experienced little disturbance tended to harbor a higher proportion of species vulnerable to fragmentation. Species in more frequently disturbed regions were more resilient. High-latitude areas historically experienced more disturbance and harbor more resilient species, which suggests that extinction has removed fragmentation-sensitive species. Thus, conservation efforts to limit fragmentation are particularly important in the tropics. Science , this issue p. 1236 ; see also p. 1196