Ecological niche models of mammalian glacial refugia show consistent bias

Ecological niche models (ENMs) are crucial tools for anticipating range shifts driven by climate change. As hypotheses of future biotic change, they can be difficult to test using independent data. The fossil record is the best way to assess the ability of ENMs to correctly predict range shifts because it provides empirical ranges under novel climate conditions. We tested the performance of ENMs using fossil distributions from the Last Glacial Maximum (LGM, ∼21 000 yr ago). We compared hindcast ENM LGM distribution hypotheses for five species of small mammals, drawn from the published literature, to the known LGM fossil record for those species and found a consistent southern prediction bias in the ENMs. This bias urges caution in interpreting future range predictions, and we suggest that the Pleistocene and Holocene fossil record should be used as an additional resource for calibrating niche modelling for conservation planning.