Assembly of plant communities

Abstract

Communities are located within a larger species pool of potential colonists. The study of community assembly considers the mechanisms by which local communities are formed from the species pool. Dispersal from the species pool, abiotic tolerance of colonists, and biotic interactions can all influence membership in local communities. Phenotypic similarities and differences of co-occurring species can be used (within limits) to make inferences about the role of alternative processes contributing to community assembly. In many plant groups, close relatives tend to share similar phenotypic traits. Therefore, patterns of phylogenetic relatedness within a community can also be used to make inferences about community assembly mechanisms. As the community and the species pool can be defined at a number of different spatial and temporal scales, community assembly patterns often show strong scale dependence. In some cases, a single process can produce contrasting phenotypic patterns at different scales of analysis, while in other cases different processes may have stronger influences on community assembly at different scales. Species pools are shaped by dispersal of lineages among biogeographic regions, in situ speciation within regions, and extinction. The characteristics of the species pool often persist in local community patterns. Community assembly studies are often limited in the extent to which specific mechanisms can be inferred from community pattern. Future work should focus on improved models of competition and coexistence dynamics in community assembly as well as methods for considering multitrophic interactions.