Assessment of the ecological health of Geumchon stream using fish, benthic macroinvertebrate, and periphyton

Abstract

An urban stream is currently being reconstructed as an ecological stream in Paju City, Korea. The diversity of fish, benthic macroinvertebrates, and periphyton in Geumchon stream was investigated, and the condition of the ecological health was assessed using the physicochemical condition of the water system. The goal is to use the data from this investigation to contribute to the establishment of policy for the conservation of Korea’s water environment. Samples of fish, benthic macroinvertebrates, and periphyton were collected from three sampling sites along the river a total of five times during the period October 2015 to June 2018 to determine the ecological structure of the Geumchon stream and its need for restoration. Samples of water and sediment were collected five times from five sampling sites for analysis of the physiochemical properties of the stream. Four families and ten species of fish were found with a total of 339 individuals. The fish found in the stream included the Carassius auratus, the Pseudorasbora parva, and the Oryzias sinensis, most of which are tolerant of water pollution. The relative richness index for Carassius auratus, Oryzias sinensis, Hemiculter eigenmanni, and Pseudorasbora parva was 52.5, 16.5, 12.7, and 12.4%, respectively. The predominant benthic macroinvertebrates observed at most sites were the Chironomidae sp. The dominant periphyton from 2015 to 2017 was the Nitzschia palea and in 2018 the Oscillatoria sp. Using the benthic macroinvertebrates index (BMI), the fish assessment index (FAI) and the trophic diatom index (TDI), the environmental condition ranged from moderate (C grade) to bad (D grade). The predominant species caught reflect the turbulent condition of the urban stream due to its reconstruction and the pollution. The biological indices (BMI, FAI, and TDI) and the physicochemical water items (BOD) were assessed separately to identify the quality of the water in the stream. The application of these biological assessments together with the chemical properties of the water can be used to provide a composite picture of the ecological health of a water system and to identify disturbances to its current condition.