An explicit test of Pleistocene survival in peripheral versus nunatak refugia in two high mountain plant species

Pleistocene climate fluctuations had profound influence on the biogeographic history of many biota. As large areas in higher latitudes and in high mountain ranges were covered by glaciers, biota were forced either to peripheral refugia (and possibly beyond to lowland refugia) or to interior refugia (nunataks), but nunatak survival remains controversial as it solely relies on correlative genetic evidence. Here, we test hypotheses of glacial survival using two high alpine plant species (insect-pollinated Pedicularis asplenifolia and wind-pollinated Carex fuliginosa) in the European Alps. Employing the iDDC (integrative distributional, demographic and coalescent) approach, which couples species distribution modelling, spatial and temporal demographic simulation and Approximate Bayesian Computation, we explicitly test three hypotheses of glacial survival: (1) peripheral survival only, (2) nunatak survival only, and (3) nunatak plus peripheral survival.