Nested species assemblages of amphibians and reptiles on islands in the Laurentian Great Lakes

• Published in: Journal of Biogeography
• Main Authors: Hecnar, S. J., Casper, G. S., Russell, R. W., Hecnar, D. R., Robinson, J. N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2002
• Subjects: Ecology; Ecology, Evolution, Behavior and Systematics; Ice Sheet
• Online Access: http://dx.doi.org/10.1046/j.1365-2699.2002.00686.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2699.2002.00686.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2699.2002.00686.x

Aim The amphibians and reptiles of the Great Lakes are diverse in their basic biology and natural history. These species are also widely distributed and overlap highly in their spatial extent. The Great Lakes basin includes 35,000 islands that differ in aspects of their geography, geology and climate, but that share a common post‐glacial history. This system provides a unique opportunity to assess the relative importance of biotic vs. abiotic factors in the development of nestedness. Our goal was to document and explain the patterns of nestedness across a variety of spatial and taxonomic scales. Location We studied amphibian and reptile assemblages (forty‐five species) occurring on 107 islands among four archipelagoes (Lake Erie, St Lawrence, Georgian Bay, Apostle) in the Laurentian Great Lakes of North America. The entire basin was recolonized in the post‐Pleistocene by amphibians and reptiles following the final retreat of the Wisconsin ice sheet. The present configuration of lakes and islands has existed over the past 5000 years. Most islands are landbridges; however, lake level fluctuation in Lake Huron inundated some islands of low relief. Presumably most islands would contain primarily extinction – as opposed to colonization – driven faunas. Methods We used data from four recent and thorough surveys to construct presence–absence matrices. To quantify nestedness of assemblages we used the nested temperature ( T ) method. To assess the association of nestedness with area and isolation we used the departures method. To quantify nestedness at the species level we used the Wilcoxon two‐sample method. To analyse species richness and patterns of nestedness we used multiple regression, and two‐way ANOVA . Results Islands supported diverse assemblages of both amphibians and reptiles that were in harmony with their mainland species pool(s). We found highly significant nestedness across the entire basin, all archipelagoes and all taxonomic levels. However, the degree of nestedness did not differ significantly among ...