Community assembly and species traits

There is perhaps no more fundamental question in ecology than what determines the number and kinds of species found in a community and their relative abundances. This chapter lays out a powerful approach to answering this question, based on the concepts of a regional species pool and environmental filters. The species pool is the set of species that could potentially colonize a local site or community. Of these potential colonists, some species are limited in their ability to disperse to site, some are limited by their ability to survive the abiotic environment, and some are limited by their interactions with other species. These “filters” act individually or in concert, and the functional traits of species determine their success in passing through these filters to colonize a local site. There is growing empirical evidence that both abiotic and biotic processes select for specific functional traits. Focusing on the functional traits of species may lead to rules of community assembly that are general and help unify a variety of more specific theories.