Effects of low-head dam removal on benthic macroinvertebrate communities in a Korean stream

Abstract

This study was conducted to examine how a low-head dam removal (partial removal) could affect benthic macroinvertebrate communities in a stream. Benthic macroinvertebrates and substrates were seasonally sampled before and after dam removal (March 2006ÁApril 2007. Benthic macroinvertebrates and substrates were quantitatively sampled from immediately upstream (upper: pool) and downstream (lower: riffle) sites, the location of the dam itself (middle), and immediately above the impoundment (control: riffle). After the removal, species richness and density of benthic macroinvertebrates as well as the EPT group (Ephemeroptera, Plecoptera and Trichoptera) increased to higher levels than those before the removal, while functional feeding groups and habitat orientation groups changed more heterogeneously at the upper site. At the lower site, species richness and density decreased somewhat immediately after dam removal, which was associated with an increase of silt and sand, but recovered after monsoon floods which helped to enhance substrate diversity at the upper site. Decreased dominance index and increased diversity index in both the upper and lower sites are evidence of positive effects from the dam removal. In conclusion, we suggest that even a partial removal of a dam, resulting in increased substrate diversity in the upper site, could sufficiently help rehabilitate lost ecological integrity of streams without major habitat changes.

Ecosystem Restoration on Santa Catalina Island: A Review of Potential Approaches and the Promise of Bottom-Up Invader Management

“…Water impoundment removal has become more common worldwide over the past 2 decades in an attempt to restore river and stream processes (e.g., Hansen and Hayes 2012, Kil and Bae 2012, Renofalt et al 2013. Reestablishing natural hydrologic processes aids in invasive species control and restoration in desert river and riparian oak ecosystems (Stromberg andChew 2003, Bossard andRandall 2007).…”

Response of benthic macroinvertebrates to dam removal in the restoration of the Boardman River, Michigan, USA

“…Release of sediment, upstream downcutting, and change in water temperature following dam removal affect composition of macroinvertebrate communities at least in the short term [12,19,21], often resulting in an initial decline in macroinvertebrate density, especially of more environmentally sensitive taxa [22]. Following initial disturbance, dam removal has been shown to be an effective means of increasing benthic macroinvertebrate diversity and abundance of environmentally sensitive macroinvertebrates [23,24]. Just as there have been relatively few ecological assessments of dam removal, there have also been only a limited number of studies of effects of dam removal on macroinvertebrate communities, especially studies lasting more than three years [15].…”

“…to be an effective means of increasing benthic macroinvertebrate diversity and abundance of environmentally sensitive macroinvertebrates [23,24]. Just as there have been relatively few ecological assessments of dam removal, there have also been only a limited number of studies of effects of dam removal on macroinvertebrate communities, especially studies lasting more than three years [15].…”

Effects of Sediment Released from a Check Dam on Sediment Deposits and Fish and Macroinvertebrate Communities in a Small Stream

“…To monitor the ecological response, fish assemblages, macroinvertebrate communities, and riparian vegetation are frequently measured. Species richness and density of macroinvertebrates have been observed to decrease temporarily and then recover gradually with increasing diversity over a long term [17][18][19][20]. Upstream movement of fish such as Salmoniformes or anadromous species has been observed after dam removal [21,22].…”