Community Structure and Diversity across Spatial Scales of Macro-benthos in the Hwang River

Abstract

Biological assessments of the macro-benthos community were carried out in the Hwang River from May 2009 to November 2010. The collected macro-benthos from the surveyed sites (St.) comprised 72 species belonging to 46 families, 17 orders, and four divisions. The emergence of species and individuals were dependent on the type and location of riverbed where they grew. St. 5, St. 7, and St. 9 had similar types of biomass, as their riverbeds were composed of boulders, gravel, etc., whereas St. 5, St. 6, St. 8, and St. 10 were located in sandy beds; therefore, featured similar benthic animals. Biomass tended to decrease on moving downstream along the river. Arthropods dominated the macro-benthos community both numerically (at individual level) and quantitatively (at species level), with a dominance of 84.7 % at the level of species. Mollusca showed the second highest dominance of 8.3 %, while Annelida and Platyhelminthes comprised 5.6 % and 1.4 %, respectively. Eight of every ten sites (80 %) were oligosaprobic according to the saprobic determination. Only two sites, St. 6 and St. 8, were -mesosaprobic.