Incipient road to extinction of a keystone herbivore in south-eastern Europe: Harting’s vole (Microtus hartingi) under climate change

Climate forcing, which is blamed for the decennial decline in the dynamics of vole populations in Central and Northern Europe, may have similar effects in southern (Mediterranean) Europe, even more so since the region is especially vulnerable to global change. In the absence of population monitoring, we investigated the temporal development and geospatial pattern of the habitat of Harting’s vole (Microtus hartingi) in southeast Europe (SEE) by relying on data regarding its presence, the most recent freely available geospatial datasets and state-of-the-art presence-only Species Distribution Modelling (SDM) techniques. Results indicate that (1) the potential habitat of Harting’s vole was perhaps stable over the last 6000 years - modelling predictions are in conjunction with scarce fossil evidence, which points to repeated colonisations from Asia Minor punctuated by extinctions in SEE; (2) fragmentation of the potential habitat in SEE, which may have already begun in the Last Glacial Maximum, and will most likely continue in the near future; and (3) Harting’s vole could disappear by the end of the century if more pessimistic climate change scenarios become reality. While climate change is suppressing the population dynamics of the keystone grass-eating voles from temperate and boreal ecosystems, it is about to annihilate their Mediterranean counterpart. This will result in a far more severe impact on community restructuring in the Mediterranean ecosystems than elsewhere. Long-term population monitoring is desperately needed in SEE to hone the ability to more accurately predict the impacts of climate change.