Diversity of infaunal macrobenthic community in the intertidal zone of Vellar estuary (Southeast coast of India)

Abstract

The diversity and seasonal variations of an intertidal macrobenthic communities link with abiotic variables were investigated in the Vellar estuary, Southeast coast of India. Samples were collected seasonally over a one year period from four different transects based on salinity gradients. Totally twelve infaunal groups were isolated which contained 53 species representing major taxa. Gastropods were the dominant group (81.6%), followed by polychaetes (7.7%), bivalves (5.5%) and amphipods (5.2%). Among these Cerethedia spp. contributed 61% of all gastropods. The macrobenthic community abundance found maximum at transect II (39%) and a minimum at transect IV (15%) while seasonally higher during summer (41%) and lower during monsoon (8%). Diversity (H' log) values varied from 1.859 (transect IV – monsoon) to 2.467 (transect II –summer). Higher diversity and species richness found in transect II due to the artificial mangrove vegetation is playing a major role on this region. Univariate and multivariate statistical analysis clearly define the interaction between biotic and abiotic variables. The results were compared with the early investigations, more or less similar community structure and species composition explained there is no changes on community structure in this estuarine environ, while higher species diversity in the transect II due to the artificial mangrove vegetation.