Issues of spatial, taxonomic and temporal scale in delineating links between mangrove diversity and ecosystem function

This paper reviews the presence of many types of spatial and temporal heterogeneity in mangrove systems, evaluates the significance of this heterogeneity, and asks if there are appropriate and useful means to generalize across scales and to incorporate this heterogeneity into models of ecosystem function. Genetic variation manifests itself at organizational scales from blanches to populations (encompassing hierarchical spatial scales from centimeters to kilometres), with phenotypic differences in physiological and morphological traits that influence the diversity of mangrove associates and ecosystem-level processes. protocols for censusing mangrove diversity and for characterizing ecosystem-level functional parameters must account for intra- and inter-specific differences within mangrove stands, the phenomenon of species zonation within swamps, and physiognomic differences among swamps in order to generate data that are amenable to spatial modelling. Identification of meaningful taxonomic units and functional groups as well as appropriate landscape-level metrics to describe mangroves may simplify this strategy, Moreover, mangroves vary in rime as well as space. Just as mangrove communities differ temporally in terms of their disturbance and colonization history, successional status, and geomorphological age, so, too, will ecosystem-level functional parameters vary over tidal cycles, seasons, and stages of stand development. Such temporal variation must be accounted for in comparative studies of swamps. Mangrove community diversity and ecosystem function should be quantified on congruent scales appropriate to detecting correlation, and manipulative experiments must be devised at appropriate scales to test for causality.