Mapping potential global change impacts on biodiversity important areas of the contiguous US

Abstract

Global trends illustrate unprecedented declines in biodiversity. The main threats driving these trends include climate change, land- and sea-use change, pollution, over-exploitation, and invasive species. Strategic allocation of conservation resources is critical to address the drivers of biodiversity loss and safeguard biodiversity and its benefits to people. However, spatial assessments quantifying the relative potential impact of these drivers on important biodiversity areas are lacking at meaningful scales for national decision making. Here, we describe the distribution and intensity of the five main threats to biodiversity loss and their spatial overlaps with areas of relatively high terrestrial and freshwater biodiversity importance in the contiguous U.S. (CONUS). Proxies for each threat are based on publicly available spatial data considering both current and future projections when possible. We assess threat intensity in relation to protected area boundaries and biodiversity important areas, and quantify deviations in threat exposure between ecoregions and national scales. Overall, 41% of CONUS are areas of high conservation concern (i.e., medium-high biodiversity value and cumulative threat risk), concentrated along eastern and western coastal regions. Combined areas of highest threat intensity (90th percentile) also cover 40% of CONUS, and almost 20% are within current protected area network, leaving a significant amount of high threat intensity areas exempt from legislative protections. We found imperiled biodiversity exposure to individual and cumulative threats varies by geographic region and taxonomic group. We propose areas of low biodiversity importance but high threat intensity as candidates for policies aimed at preserving ecosystem intactness and human health. Our threat mapping assessment provides a baseline for conservation priorities across scales and could be used to develop spatially explicit guidance for mitigating threats to imperiled biodiversity in CONUS.