Habitat loss is the greatest threat to biodiversity and rapid, human-forced climate change
is likely to exacerbate this. Here we present the first global assessment of current and
potential future impacts on biodiversity of a habitat loss and fragmentation–climate change
(HLF–CC) interaction. A recent meta-analysis demonstrated that the negative impacts of
habitat loss and fragmentation have been disproportionately severe in areas with high
temperatures in the warmest month and declining rainfall, although impacts also varied
across vegetation types. We compiled an integrated global database of past, current and
future climate variables and past vegetation loss to identify ecoregions where (i) past
climate change is most likely to have exacerbated the impacts of HLF, and (ii) forecasted
climate change is most likely to exacerbate the impacts of HLF in the future. We found that
recent climate change is likely (probability>66%) to have exacerbated the impacts of HLF in
120 (18.5%) ecoregions. Impacted ecoregions are disproportionately biodiverse, containing
over half (54.1%) of all known terrestrial amphibian, bird, mammal, and reptile species.
Forecasts from the RCP8.5 emissions scenario suggest that nearly half of ecoregions globally
(n = 283, 43.5%) will become impacted during the 21st century. To minimize ongoing and
future HLF–CC impacts on biodiversity, ecoregions where impacts are most likely must
become priorities for proactive conservation actions that avoid loss of native vegetation
(e.g., protected area establishment). Highly degraded ecoregions where impacts are most
likely should be priorities for restoration and candidates for unconventional conservation
actions (e.g. translocation of species).