Crustaceans functional diversity in mangroves and adjacent mudflats of the Persian Gulf and Gulf of Oman

The effects of mangrove vegetation on functional features of crustacean assemblages were investigated using the Biological Traits Analysis (BTA). The study was carried out at four major sites in the arid mangrove ecosystem of the Persian Gulf and Gulf of Oman. Samples of Crustacea and associated environmental variables were taken seasonally (February 2018 and June 2019) from two habitats: a vegetated area with both mangrove trees and pneumatophores, and an adjacent mudflat. In each site, functional traits for the species were assigned using seven categories based on bioturbation, adult mobility, feeding habits and life-strategy traits. The results showed that the crabs (i.e., Opusia indica, Nasima dotilliformis and Ilyoplax frater) were widely distributed across all sites and habitats. The vegetated habitats supported higher taxonomic diversity than the mudflats, which highlights the importance of mangrove structural complexity for crustacean assemblages. Species inhabiting vegetated habitats were characterized by stronger presence of conveyor building species, detritivore, predator, grazer, lecithotrophic larval development, body size of 50-100 mm, and swimmer trait modalities. While, mudflat habitat enhanced the occurrences of surface deposit feeder, planktotrophic larval development, body size of <5 mm, and life span of 2-5 years. The results of our study showed that taxonomic diversity increased from the mudflats to the mangrove vegetated habitats. However, functional diversity did not differ between habitats. The significant differences in species and functional trait composition were observed between vegetated habitats and adjacent mudflats, stressing that different habitats may harbor different species and trait sets, likely as a result of habitat complexity. The use of taxonomic and functional attributes generate complementary information that can helps us to reach more efficient conclusions in terms of biodiversity conservation and ecosystem functionality in mangrove ecosystems.