The impact of the Goesan dam on fish communities up- and downstream

Abstract

Dams can cause fragmentation of the natural structure and function of fish communities up-and downstream of the dam. In this study, we examined the effects of the Goesan Dam on the longitudinal distribution of fish in the Dal stream, using two computational methods: a self-organizing map (SOM) and spatial autocorrelation. Fish were collected at 16 different study sites in two seasons (spring and autumn). SOM classified the study sites into four clusters (1-4), reflecting differences in the longitudinal distribution patterns of fish, and the effects of the dam on fish community composition. Samples in clusters 1 and 2 mostly originated from tributaries and the upstream section of the dam, whereas samples in cluster 4 originated from downstream study sites of the dam. Cluster 3 included study sites originating directly from up-and downstream of the dam. Species turnover and spatial autocorrelation results confirmed the fish community alteration near the dam. Species turnover was the highest between study sites directly up-and downstream of the dam. The Mantel correlogram was positive when applied to short distances between the study sites. However, it was negative for the farthest distance, including sites near the dam, indicating that the dam caused significant alterations to the fish community. Overall, our results suggest that the habitat alterations (e.g., fragmentation of longitudinal gradients and disruption of flow regimes) due to dam construction have caused fragmentation of fish communities.

Aquatic ecosystem assessment and management

“…Global warming has profound effects on the distribution and phenology of species, affecting biodiversity (Kwon et al, 2015), and it has already had observable effects on ecosystems worldwide, and an accelerated rate of global change is predicted in the future (Li et al, 2013(Li et al, , 2014. Song et al (2016) examined the effects of damming on the longitudinal distribution of fish in a Korean stream, using two computational methods: a self-organizing map (SOM) and spatial autocorrelation. Study areas were classified into four clusters in SOM, reflecting differences in the longitudinal distribution patterns of fish and the effects of the dam on fish community composition.…”

Annual shifts of flow regime alteration: new insights from the Chaishitan Reservoir in China

“…As a leading country of dam construction, China has built approximately 86 thousand dams, which accounted for over half of the world’s total by the end of 2007 2 . Recently, concerns have been raised regarding the effects of global dam construction and regulation on natural water cycle in terms of river geomorphology changes/connectivity disruption and sediment budgets 8 , 9 , hydrological variability reduction 10 , 11 , surface water pollution and eutrophication 12 , 13 , and biotic diversity degradation 14 , 15 , among others. Therefore, it is urgent and critical to quantify the impact of dam regulation on flow regimes to provide scientific support to optimize the regulation rules of dams.…”

Functional Trait Analysis and the Multi-metric Integrity Model, Based on Stream Fish Indicators, and Their Relations to Chemical Water Quality

“…These findings were attributable to the dam. According to the previous study, fish communities in the upper and lower reaches of Goesan Dam differed markedly, based on species turnover rate and spatial autocorrelation (Song et al, 2016). They suggested that the loss of longitudinal continuum and disruption of flow regimes caused by the dam explain the fragmentation of fish communities in the stream.…”

“…It originates from Mount Songnisan, passes through Goesan County, and joins the Namhan River west of Chungju City. The catchment area is 1614.4 km 2 and the river is almost 116 km in length (Song et al, 2016). The geographical location of the stream and its monitoring sites are shown in Fig.…”