Intraspecific Niche Variation and Individual Specialization

Intraspecific niche variation, within an apparently generalist population, may be largely due to specialized individuals. That is, particular individuals specialize on a sub-set of the diverse prey items available, and thus differ in resource use from con-specifics. Despite a tradition that considered such “individual specialization” within a species to be rare or weak, recent studies have suggested it is widespread and can play a critical role in ecological and evolutionary processes. Our lab has explored such intraspecific niche variation with a variety of approaches, including direct diet analysis, stable isotopes, tracking animal movement patterns, morphometrics and theoretical and conceptual models. Much of this work was focused on Bahamian tidal creeks, exploring how how ecosystem fragmentation may drive patterns of resource use variation among individuals. Collaborative projects have been conducted in many other ecosystems (Loxahatchee River, FL; Shark Bay, Australia; Curacao; The Everglades), which has lead to a more general understanding of when and how intraspecific niche variation is most likely to affect food web structure and dynamics.