Edinburgh Napier University

  With only about 80 species of true mangrove trees worldwide, mangrove ecosystems comprise a relatively low number of habitat-forming tree species, but a high diversity of decomposer, detritivorous and consumer species. Although the overall level of diversity in mangrove ecosystems is low relatively to those of other key tropical habitats such as coral reefs and tropical rain forests, these species collectively support many important ecosystem services. Here, we report the broad variety of key functional and structural biodiversity components of mangrove ecosystems, with particular emphases on the decomposer, the macrobenthic invertebrate and finfish assemblages and their roles in key ecological processes. Attempt is also made to compare the biodiversity of selected groups associated with the two main biogeographic regions of habitat-forming mangroves: the species-rich Indo-West-Pacific (IWP) and the species-poor Atlantic-East-Pacific (AEP). Analysis of global data suggests that the IWP mangrove wetlands support significantly higher species richness of finfish than AEP systems, despite similar patterns of variation with latitude. While data on the other biodiversity components to date are not sufficient for an overall comparison between the two biogeographic regions, a similar difference, if existing, may have implications for the function and, therefore, ecosystem services. Mangrove biodiversity is increasingly threatened by the continual loss of mangrove forests and sustained degradation due to anthropogenic threats such as seawall construction, pollution and sea level rise. Studies on global mangrove ecosystems may contribute significantly to the understanding of the relationship between diversity and ecosystem function.