Patterns of structural and functional diversity of macrofaunal communities in a subtropical mangrove ecosystem

Biological trait analysis has been successfully used to describe ecological functions in marine benthic ecosystems. However, it has rarely been applied to mangrove habitats. This study analyzes taxonomic and functional diversity and the components thereof in two mangrove habitats in the Hara Biosphere Reserve, Persian Gulf: a vegetated area with both mangrove trees and pneumatophores, and an adjacent mudflat. Species diversity and functional diversity were higher in vegetated habitats and slightly increased in summer. Our study demonstrates the importance of mangrove structural complexity for the structure and functioning of invertebrate communities. The macrofaunal communities were characterized by low diversity and a high dominance of just a few species, such as crab Opusia indica which are specifically adapted to this stressed environment. Burrowers, surface deposit feeders, free-living, and large sized organisms were dominant trait modalities that essentially shape the functional composition of arid mangrove ecosystem of the Persian Gulf. The low functional redundancy among species implies that small changes in species diversity may have marked impacts on the system functional diversity.