Macroecology of mangroves: large-scale patterns and processes in tropical coastal forests

Abstract.

Macroecology is an emerging subdiscipline within ecology that explores effects of large-scale processes on local, regional, and global patterns of species diversity and taxon-independent scaling of structural and functional relationships. Statistical analysis of these patterns yields hypotheses concerning the processes determining population, community, and ecosystem-level patterns, which have been the historical focus of most ecological research, including that done in mangroves. The majority of studies of mangrove forests have aimed to better understand the causes of local (within-forest) ecological patterns (e.g. zonation, tolerance to salinity and hypoxia, litterfall and production), with little attention to the larger environmental, historical and evolutionary contexts that can influence local processes. I argue that a focus on the larger-scale contexts that constrain local processes (a "macroecology of mangroves") will provide us with new insights into the structure and function of mangrove ecosystems. Further, such analyses can be used to determine if mangroves follow similar general rules that have been identified for upland forested ecosystems. I consider two examples: relationships between local species richness and latitude, longitude and regional diversity; and structural coordination of leaf traits. I present data and analyses of these macroecological patterns in mangrove forests, and illustrate points of agreement and disagreement between these and upland ecosystems. I suggest that ecological theory developed in upland forests can be readily applied to mangrove forests. Such a conclusion should lead to advances in ecological research of mangroves and better predictions of how they will respond to global climate change.