Document Type
Article
Journal/Book Title/Conference
Global Ecology and Biogeography
Volume
16
Publisher
Willey-Blackwell
Publication Date
2007
First Page
257
Last Page
264
Abstract
Discerning the processes influencing geographic patterns of species richness remains one of the central goals of modern ecology. Traditional approaches to exploring these patterns have focused on environmental and ecological correlates of observed species richness. Recently, some have suggested these approaches suffered from the lack of an appropriate null model that accounts for species’ ranges being constrained to occur within a bounded domain. Proponents of these null geometric constraint models (GCMs), and the mid-domain effect these models produce, argue their utility in identifying meaningful gradients in species richness. This idea has generated substantial debate. Here we discuss what we believe are the three major challenges in the application of GCMs. First, we argue there are actually two equally valid null models for the random placement of species ranges within a domain, one of which actually predicts a uniform distribution of species richness. Second, we highlight the numerous decisions that must be made to implement a GCM that lead to marked differences in the predictions of the null model. Finally, we discuss challenges in evaluating the importance of GCMs once they have been implemented.
Recommended Citation
McClain, C.R., E.P. White, and A.H. Hurlbert. 2007. Challenges in the application of geometric constraint models. Global Ecology and Biogeography 16:257264.
