Forecasting the effects of climate change on species and populations is a fundamental goal of conservation biology, especially for montane endemics which seemingly are under the greatest threat of extinction given their association with cool, high elevation habitats. Species distribution models (also known as niche models) predict where on the landscape there is suitable habitat for a species of interest. Correlative niche modeling, the most commonly employed approach to predict species' distributions, relies on correlations between species' localities and current environmental data. This type of model could spuriously forecast less future suitable habitat because species' current distributions may not adequately represent their thermal tolerance, and future climate conditions may not be analogous to current conditions. We compared the predicted distributions for three montane species of Plethodon salamanders in the southern Appalachian Mountains of North America using a correlative modeling approach and a mechanistic model. The mechanistic model incorporates species-specific physiology, morphology and behavior to predict an annual energy budget on the landscape. Both modeling approaches performed well at predicting the species' current distributions and predicted that all species could persist in habitats at higher elevation through 2085. The mechanistic model predicted more future suitable habitat than the correlative model. We attribute these differences to the mechanistic approach being able to model shifts in key range-limiting biological processes (changes in surface activity time and energy costs) that the correlative approach cannot. Choice of global circulation model (GCM) contributed significantly to distribution predictions, with a tenfold difference in future suitability based on GCM, indicating that GCM variability should be either directly included in models of species distributions or, indirectly, through the use of multi-model ensemble averages. Our results indicate that correlative models are over-predicting habitat loss for montane species, suggesting a critical need to incorporate mechanisms into forecasts of species' range dynamics.
Bibliographical noteFunding Information:
). Data are available from the Dryad Digital Repository: < http://dx.doi.org/10.5061/dryad.qz612jm9b > (Lyons and Kozak Acknowledgements – We thank M. Gifford, W. Peterman and D. Shepard for assistance with the mechanistic model as well as A. Luxbaucher and B. Weinstein for the code we adapted to create ground temperature climate layers. We are grateful to S. Rovito for providing comments on an earlier draft. We thank M. Araújo and reviewers for comments that improved the manuscript. Funding – Financial support was provided by NSF award DEB‐0949590 to KHK along with support from the Bell Museum of Natural History to MPL. Supplementary material (available online as Appendix ecog‐04282 at < www.ecography.org/appendix/ecog‐04282 >). Appendix 1–2.
- climate change
- niche model