Summer variations of macrobenthic community structures in Gwangyang Bay, South Korea

Abstract

We investigated the structure change of the macrobenthic community in Gwangyang Bay (Korea) in response to habitat alteration, using the summer fauna data collected between July 2007 and August 2015. The results showed that polychaete worms were the most abundant benthic community faunal group, and polychaetes were richest in species number and density, while mollusks accounted for the highest proportion of the total biomass. There were large variations in species richness and density and the biomass of the macrobenthic faunal communities in Gwangyang Bay that are linked to environmental perturbations that have occurred for more than a decade. There was also a change in the composition of the macrobenthic faunal community, especially in the dominant species. The most dominant benthic fauna were Heteromastus filiformis and Magelona japonica after 2007, and the dominance of Theora fragilis increased after 2008. Scoletoma longifolia dominated from 2009 to 2012, and it was still the dominant species in summer 2015. Analyses based on ANOSIM and nMDS showed significant changes in the benthic community structure during summer periods from 2007 to 2015. In particular, the benthic community in 2015 differed from other summer communities because of the decreased occurrence of T. fragilis. The temporal changes in the faunal composition suggest that the changes were related to long-term changes in habitat conditions brought abou