When populations reside within a heterogeneous landscape, isolation by distance may not be a good predictor of genetic divergence if dispersal behaviour and therefore gene flow depend on landscape features. Commonly used approaches linking landscape features to gene flow include the least cost path (LCP), random walk (RW), and isolation by resistance (IBR) models. However, none of these models is likely to be the most appropriate for all species and in all environments. We compared the performance of LCP, RW and IBR models of dispersal with the aid of simulations conducted on artificially generated landscapes. We also applied each model to empirical data on the landscape genetics of the endangered fire salamander, Salamandra infraimmaculata, in northern Israel, where conservation planning requires an understanding of the dispersal corridors. Our simulations demonstrate that wide dispersal corridors of the low-cost environment facilitate dispersal in the IBR model, but inhibit dispersal in the RW model. In our empirical study, IBR explained the genetic divergence better than the LCP and RW models (partial Mantel correlation 0.413 for IBR, compared to 0.212 for LCP, and 0.340 for RW). Overall dispersal cost in salamanders was also well predicted by landscape feature slope steepness (76 %), and elevation (24 %). We conclude that fire salamander dispersal is well characterised by IBR predictions. Together with our simulation findings, these results indicate that wide dispersal corridors facilitate, rather than hinder, salamander dispersal. Comparison of genetic data to dispersal model outputs can be a useful technique in inferring dispersal behaviour from population genetic data.
Bibliographical noteFunding Information:
Acknowledgments We thank shirli Bar David, arne nolte, sebastian steinfartz and Ori segev for fruitful discussion, and three anonymous reviewers for their detailed suggestions. This research was carried out under Israel national Parks authority permit number no. 2009/36565. It was partly funded by Israel science Foundation (IsF) grant 961-2008 awarded to leon Blaustein, shirli Bar-David, and alan Templeton, and by an academy of Finland grant awarded to Juha Merilä. arik Kershenbaum was provided with a doctoral scholarship by the University of haifa and by the IsF grant. Part of this work was conducted while arik Kershenbaum was a Postdoctoral Fellow at the national Institute for Mathematical and Biological synthesis, an institute sponsored by the national science Foundation (nsF), the Us Department of homeland security, and the Us Department of agriculture through nsF award no. eF-0832858, with additional support from the University of Tennessee, Knoxville. This study was partially funded by the Deutsch-Israel Project no. Bl 1271/1-1 awarded to leon Blaustein, alan Templeton, sebastian steinfartz and arne nolte.
- Circuit theory
- Isolation by distance
- Isolation by resistance
- Landscape genetics
- Least cost path
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics