Spatially Well Structured Mangroves Fish Communities of the Persian Gulf; a Functional Perspective

Abstract

Abstract Functional diversity is one of the most important aspects of biodiversity studies. In this work, the functional diversity of two mangrove-associated fish communities in the Persian Gulf is evaluated, including 34 species from the estuary community and 23 species from the creek/mud community. For each community, three functional diversity indices were calculated, namely, FD (Functional Diversity, representing functional richness), MPD (Mean Pairwise Distance, representing dispersion), and MNTD (Mean Nearest Taxon Distance, representing evenness). The comparison between the observed values and the expected values indicates the low functional diversity of the estuary community, whereas, the functional diversity of the species inhabiting creeks and mud flats was not significantly lower or higher than the expected functional diversity. Moreover, the dispersion of functional traits in creek/mud species was higher and the evenness was lower than the estuaries community. This can be related to the more homogenous habitat of the estuary environment, in comparison with the creeks and mudflats. Also, we can attribute the low functional diversity of the estuary community to both the homogenous structure and the preliminary situation of the Persian Gulf. Dendrogram-based analyses show four functional guilds in both communities and were used to the recognition of the most important species for the functional diversity in each community. We found that the most important functional traits that explain the functional diversity in the estuary community were the general traits of size and position in the vertical column in water, however, in creek/mud communities more specialized traits such as the feeding habit and the migratory status explain most of the diversity.