A functional group approach for predicting the composition of hard coral assemblages in Florida and Bermuda.

摘要

In Florida the functional-group approach provided new insights into the manner in which varying levels of disturbance affected species richness across sites. Despite the chaotic patterns in biomass displayed by each assemblage of coral species when separately plotted across reefs, each functional group of corals responded to direct and indirect gradients of disturbance in a orderly and group-specific manner. Functional groups displayed a nested distributional pattern, indicating that negative interactions between functional groups are probably weak.;Terrestrial and marine ecologists have found that a functional group approach can accurately predict how organisms will respond to changes in environment conditions. A functional group approach categorizes organisms, regardless of phylogeny, according to similarities and differences in life history and other ecologically relevant traits. One such model, the "CSR plant strategy theory" developed by Phillip Grime in 1973 for terrestrial plants, predicts the assemblage structure of biota over gradients of stress and disturbance. To test the CSR model, coral assemblages on reefs from Florida and Bermuda were assessed at the hierarchical levels of species and functional groups. The data were used to address the question of whether the functional-level approach provides information about community structure that species-level analysis fails to provide. Additionally, the predictions of the CSR model were tested regarding how coral cover, species diversity and assemblage structure should vary in habitats characterized by differing levels of disturbance and resource-limitation.;In Bermuda, functional groups of corals also displayed a nested pattern across sites located over a range of depths and reef zones. When species were aggregated according to shared habitat, species from the same genus co-occurred in almost every case. This implies that these closely related species also share many functional traits and yet still coexist in many habitats. The Adaptive Strategies Theory provides a series of simple, testable hypotheses that can be used to guide ecological research in an iterative and informative manner.;The Adaptive Strategies Theory is a powerful theoretical framework, which can be modified to give it great heuristic value for guiding ecological research.