AbstractsBiology & Animal Science

Various ecological processes affect generalist and specialist species differently. By measuring niche breadth in communities, we can infer those processes. Simulation models provided proofs of concept for three analyses that were applied to Carolina Vegetation Survey data. (1) A refined method for estimating niche breadth using co-occurrence data is presented. (2) It is shown that sampling grain can affect the quality of such estimates and also illuminate the scale of the processes limiting species' distributions. Trees showed surprising sensitivity to spatial variation at a small scale (10cm2) while herbs responded more strongly at a larger one (1000m2). (3) The relationship between assemblage richness and the generalism of its members is explored. There is evidence that in some community types, important factors affecting richness include an evolutionary generalism-competition trade-off and the availability of specialist competitors in the local pool.