Spatial and temporal variability of sandy intertidal macrobenthic communities and their relationship with environmental factors in a tropical island

Abstract

Spatial and temporal variability of macrobenthic community in intertidal habitats is governed by various physicochemical factors. Finding the relationship between environmental parameters and the biotic element of an ecosystem have been the centre of ecological studies. This paper describes the influence of environmental parameters in structuring the benthic community at spatial and temporal scales. Samplings were carried out on seasonal basis for a period of two years (August 2013 to July 2015). Fauna was collected from three soft-bottom intertidal locations (CH, MP and CT) using 25 × 25 cm quadrat along the Port Blair coast, south Andaman, India. A total of 112 macrofaunal taxa belonging to 4 major and 2 minor phyla were recorded. Polychaeta was the most dominant taxa followed by Amphipoda. Statistical analyses revealed that macrobenthic faunal assemblages were significantly different at spatial scale but not on temporal pattern. The distribution of macrobenthic fauna at spatial scale was mainly influenced by sediment characteristics (organic matter and grain size). Amphipods dominated the locations where sediment having coarser grain size and low organic matter whereas polychaetes and molluscs were found abundant at the locations characterised with fine sediment and high organic matter. This study concludes that in the regions where temporal variability is not significant, the sediment characteristics, which together with beach morphodynamics play an important role in structuring the benthic community.