Amphibians are experiencing population declines far exceeding those of other vertebrate groups. The exact causes of these declines are still a matter of controversy but most likely include climate change, land-use change and the spread of Chytridiomycosis, a disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (or Bd for short). Several hypotheses have been proposed on the potential interactions between major threats, namely Bd and climate change, yet no final accord has been reached. First models of the geography of Bd under climate change have been provided, but to date an integrative, global-scale assessment on the spatial interactions of the most severe threats climate change, Bd and land-use change is missing. Here, we provide a global assessment of the geography of these potential threats and their interactions. Using a dataset of 5,527 amphibian species we demonstrate how the spatial interaction of the three most important threats (climate change, Bd, and land-use change) may impact amphibian diversity between now and 2080 in a geographically heterogeneous way.

Results/Conclusions

We show that the highest proportions of species negatively affected by climate change are projected to occur in Africa, parts of northern South America, and the Andes. Regions with highest projected climate and land-use change impacts show a strong tendency of congruence, but show little overlap with regions of high Bd prevalence. Other threats like pollution and direct exploitation may affect the exact geography of impacts, but in absolute terms only add to the already considerable threats identified. Our findings highlight that the existing declines of amphibians will most likely be exacerbated in the 21^st century as multiple drivers of extinction risk may impose a far more alarming jeopardy for global amphibian diversity than previous, mono-causal assessments have suggested. We call for more quantitative spatial assessments on the intensity and interactions of threats and stress the need of multi-level conservation approaches.