HOW TO USE

This website contains paleophylogeographic species distribution models that show the changes of a species' distribution during the last 320,000 years for 59 species of Nearctic turtles. The models are presented as animated maps, along with information on current distribution and phylogeography of each species. To view a species, just select it from the drop-down menu in the top right of the page.



HOW TO CITE

Rödder D, Lawing AM, Flecks M, Ahmadzadeh F, Dambach J, Engler JO, Habel JC, Hartmann T, Hörnes D, Ihlow F, Schidelko K, Stiels D, Polly PD (2013) Evaluating the Significance of Paleophylogeographic Species Distribution Models in Reconstructing Quaternary Range-shifts of Nearctic Chelonians. PLoS ONE 8(10): e72855.

The article is freely available online at doi:10.1371/journal.pone.0072855.



BACKGROUND

The climatic cycles of the Quaternary, during which global mean annual temperatures have regularly changed by 5-10°C, provide a special opportunity for studying the rate, magnitude, and effects of geographic responses to changing climates. During the Quaternary, high- and mid-latitude species were extirpated from regions that were covered by ice or otherwise became unsuitable, persisting in refugial retreats where the environment was compatible with their tolerances. In this study we combine modern geographic range data, phylogeny, Pleistocene paleoclimatic models, and isotopic records of changes in global mean annual temperature, to produce a temporally continuous model of geographic changes in potential habitat for 59 species of North American turtles over the past 320 Ka (three full glacial-interglacial cycles). These paleophylogeographic models indicate the areas where past climates were compatible with the modern ranges of the species and serve as hypotheses for how their geographic ranges would have changed in response to Quaternary climate cycles. We test these hypotheses against physiological, genetic, taxonomic and fossil evidence, and we then use them to measure the effects of Quaternary climate cycles on species distributions. Patterns of range expansion, contraction, and fragmentation in the models are strongly congruent with (i) phylogeographic differentiation; (ii) morphological variation; (iii) physiological tolerances; and (iv) intraspecific genetic variability. Modern species with significant interspecific differentiation have geographic ranges that strongly fluctuated and repeatedly fragmented throughout the Quaternary. Modern species with low genetic diversity have geographic distributions that were highly variable and at times exceedingly small in the past. Our results reveal the potential for paleophylogeographic models to (i) reconstruct past geographic range modifications, (ii) identify geographic processes that result in genetic bottlenecks; and (iii) predict threats due to anthropogenic climate change in the future.



CONTACT

Dennis Rödder
Zoologisches Forschungsmuseum Alexander Koenig
Adenauerallee 160
D-53113 Bonn
Germany

E-mail: d.roedder.zfmk@uni-bonn.de



LINKS

The EMYSystem World Turtle Database
The Paleobiology Database