Temporal changes in benthic macroinvertebrates and their interactions with fish predators after restoration in theCheonggyecheon, a downtown stream inSeoul,Korea

Abstract

AbstractTheCheonggyecheon (Cheonggye stream), a downtown stream inSeoul,Korea, was restored by the historicCheonggyecheon Restoration Project (2003–2005), and its discharge and other environmental conditions are artificially regulated throughout the year. The aim of this study was to assess temporal changes in benthic macroinvertebrates and their interactions with fish predators in theCheonggyecheon. Sampling was conducted twice a year (spring and autumn) at three sections of the stream from 2006 to 2010 using a Surber sampler (50 × 50 cm) for benthic macroinvertebrates and a cast net (mesh size, 10 × 10 mm) and a kick net (mesh size, 5 × 5 mm) for fishes. Analyses of annual precipitation and most water quality parameters showed no significant differences across the study period (P> 0.05). The species richness and density of benthic macroinvertebrates and fishes varied across the sampling period. Analyses of functional feeding groups and trophic guilds showed distinct trends, such as an increase in the number of insectivorous fish in the absence of invertebrate predators. Correlation and regression analyses for five major groups of benthic macroinvertebrates and fishes demonstrated that the density of certain groups of benthic macroinvertebrates (e.g.Tubificidae,Erpobdellidae,Baetidae, andChironomidae) and insectivorous fishes (e.g.Gobioninae,Leuciscinae,Danioninae, andGobiidae) were negatively correlated. In conclusion, in an artificially regulated stream like the restoredCheonggyecheon, where physical environments are nearly unchanged, fish predation can be a major factor controlling benthic macroinvertebrate communities.