Applications of Ecological Niche Modeling for Species Delimitation: A Review and Empirical Evaluation Using Day Geckos (Phelsuma) from Madagascar

Abstract

Although the systematic utility of ecological niche modeling is generally well known (e.g., concerning the recognition and discovery of areas of endemism for biogeographic analyses), there has been little discussion of applications concerning species delimitation, and to date, no empirical evaluation has been conducted. However, ecological niche modeling can provide compelling evidence for allopatry between populations, and can also detect divergent ecological niches between candidate species. Here we present results for two taxonomically problematic groups of Phelsuma day geckos from Madagascar, where we integrate ecological niche modeling with mitochondrial DNA and morphological data to evaluate species limits. Despite relatively modest levels of genetic and morphological divergence, for both species groups we find divergent ecological niches between closely related species and parapatric ecological niche models. Niche models based on the new species limits provide a better fit to the known distribution than models based upon the combined (lumped) species limits. Based on these results, we elevate three subspecies of Phelsuma madagascariensis to species rank and describe a new species of Phelsuma from the P. dubia species group. Our phylogeny continues to support a major endemic radiation of Phelsuma in Madagascar, with dispersals to Pemba Island and the Mascarene Islands. We conclude that ecological niche modeling offers great potential for species delimitation, especially for taxonomic groups exhibiting low vagility and localized endemism and for groups with more poorly known distributions. In particular, niche modeling should be especially sensitive for detecting recent parapatric speciation driven by ecological divergence, when the environmental gradients driving speciation are represented within the ecological niche models.

Predicting the potential distribution of an endangered cryptic subterranean mammal from few occurrence records

“…Ecological niche models have been widely applied in conservation biology to predict the potential distributions of species using correlative models that exploit a species-environment relationship (Anderson et al, 2009;Chefaoui et al, 2005;De Siqueira et al, 2009;Peterson, 2001;Raxworthy et al, 2007;Rushton et al, 2004;Titeux et al, 2007). Ecological niche models require occurrence records and a set of environmental predictor variables in order to predict a species' potential distribution (Gaubert et al, 2006;Peterson, 2001).…”

Resurrecting an extinct species: archival DNA, taxonomy, and conservation of the Vegas Valley leopard frog

“…Further phylogeographic studies and ecological niche modeling (e.g. Raxworthy et al 2007), may provide valuable insight in resolving this pattern, and also help identify important areas of connectivity in the changing arid Southwest. The unexpected resurrection of R. fisheri via phylogenetic placement of archival specimens highlights the utility of museum collections to provide evidence of pre-anthropogenic-disturbance conditions and better defines paths toward recovery of several imperiled leopard frogs in southwestern North America.…”

Abbreviations and acronyms

“…The range of environmental and biotic conditions can be assessed through niche modelling, providing evidence for geographic isolation between populations (either based on conserved or divergent ecological niches). By mapping the spatial distribution of environmental suitability of climatic variables (Raxworthy et al, 2007), the niche modelling provides a much stronger case for geographic isolation for populations isolated by intervening unsuitable regions reducing gene flow.…”