COS 23-1 - 'Neutral' Models with Overlapping Niches

Tuesday, August 9, 2011: 8:00 AM
9AB, Austin Convention Center
Sharon A. Bewick, Bioogy, University of Maryland, College Park, College Park, MD, Ryan A. Chisholm, Smithsonian Tropical Research Institute, Panamá City, Panama, Erol Akçay, Department of Ecology and Evolutionary Biology, Princeton University and William Godsoe, Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand

Describing and predicting patterns of species richness and abundance is a central goal of community ecology. Simple neutral models, which incorporate only the basic processes of speciation, drift and (sometimes) dispersal, appear to be adequate to predict static biodiversity patterns under some circumstances. An important research goal is to analyze more biologically realistic models in order to explore the limitations of neutral models and, ultimately, to produce better predictions over a broader range of spatial and temporal scales. We build upon a simple, spatially implicit neutral model, first by incorporating overlapping niches and second by adding a specialist-generalist trade-off, according to which specialists can survive in fewer habitats than generalists but have greater fecundity.


In the absence of fecundity differences, generalists dominate the system and specialists are extremely rare. In the presence of the trade-off, specialists and generalists can co-exist. The static predictions of our model and the neutral model are very similar, at least for high-diversity systems, demonstrating the robustness of the neutral model in this case. However, the dynamic predictions of the two models are somewhat different, suggesting that dynamic biodiversity patterns may provide more sensitive tests of underlying mechanisms and that neutral models may be insufficient to capture these patterns. These results are consistent with previous theoretical results based on different mechanisms, and are also consistent with empirical observations that neutral theory is poor predictor of dynamic biodiversity patterns.

Copyright © . All rights reserved.
Banner photo by Flickr user greg westfall.