The effects of the Late Quaternary glacial-interglacial cycles on Anatolian ground squirrels: range expansion during the glacial periods?

Abstract

The present study aimed to understand how Anatolian ground squirrels, Spermophilus xanthoprymnus (Bennett, 1835), have responded to global climate changes through the Late Quaternary glacialinterglacial cycles. Accordingly, ecological niche modelling was used, together with molecular phylogeography. Using species occurrence data compiled from field observations and relevant sources and the maximum entropy machine learning algorithm in MAXENT, an ecological niche model was developed to predict the potential geographical distribution of S. xanthoprymnus under reconstructed past (the Last Interglacial, approximately 130000116000years ago and the Last Glacial Maximum, 21000years ago) and present (19502000) bioclimatic conditions. In addition, using cytochrome b mitochondrial DNA sequences deposited in GenBank and the Bayesian skyline plot in BEAST, demographic events (population fluctuations) were further assessed over the history of Anatolian ground squirrels. Combined ecological niche modelling and molecular phylogeography revealed that S.xanthoprymnus, itself also a temperate (mid-latitude) species, has responded to global climate changes through the Late Quaternary glacialinterglacial cycles in a fashion converse to that of most temperate (mid-latitude) species: its range expanded rather than contracted during the glacial periods and contracted rather than expanded during the interglacial periods. In other words, Anatolian ground squirrels have been in refugia during the interglacial periods, suggesting that the classical paradigm of glacial range contraction and interglacial range expansion for temperate species may not be as general as previously assumed.(c) 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 1932.