Kaitlin Brown– Undergraduate– Geography
The Monsoon Season’s Impacts on Stream Dynamics and Fish Assemblages in South Korea
South Korea experiences heavy monsoon seasons, which are typically accompanied with heavy rainfall and sometimes result in river and stream flooding. Flooding causes temporarily increased turbidity and suspended sediments in streams, which in turn can degrade local, small stream fish habitats by altering landscapes, and change stream depths. Human infrastructure and activities also can affect fish assemblages, due to weirs increasing the recovery times of some fish species, and the eventual eutrophication of waterways from increased chemicals, particularly phosphorus and nitrogen, in runoff from agricultural sites. In this poster, I discuss how monsoon flooding affects levels of turbidity, nitrogen, and phosphorus in streams, as well as the impacts from this on stream habitats and fish populations in South Korea.
Rian Land - Undergraduate- Forest Ecology and Management
Atlantic Salmon Response to Dam Removal in the Selune River, France
Connectivity in aquatic ecosystems is important to maintain ecosystem function in rivers. The dam removal of three dams located on the Selune River in France would increase longitudinal and latitudinal connectivity of the river by removing barriers that create habitat fragmentation. Prior to dam removal only the lower part of the river was connected to the sea, which hindered Atlantic salmon migration as they moved from saltwater to freshwater. This paper examines the effectiveness of restoring salmon populations in the Selune River following dam removal as well as the effects that the release of sediment trapped behind dams will cause to recovering salmon populations.This issue is relevant because salmon are important to the health of freshwater systems. Because salmon spend part of their life feeding in the oceans, when they travel upriver, die, and decompose they serve to transport marine nutrients from the ocean to the headwaters of rivers that may be less productive. Removing dams may have the potential to allow salmon back to the upper part of the river but dam removal also has social consequences that must be examined. The Selune River feeds various manmade reservoirs that serve as recreational sites so the removal of these dams has become a social issue as well as an aquatic ecosystem.
Lily Larsen - Undergraduate - Environmental Science
Dam Removal Impacts on Sedimentation, Fish Habitat, and Fish Populations in Japan
The construction of dams by humans have changed the way that ecosystems function for centuries. Debate over dam removal has caused two distinct camps to form: those in favor of dam removal and those opposed. This paper seeks to examine the impact of dam removal on the fish population in the Ikeshomanai and Toubatsu streams in Japan in conjunction with the evidence on how dam removal influenced sediment dispersal (and thus, fish populations and habitat) in the Kamo River in Japan. The impacts of dams are many and varied, and this study focuses on examining how dam removal may influence sedimentation, fish habitat, and fish populations within certain aquatic ecosystems in Japan. The partial removal of a dam in the Ikeshomanai-Toubatsu system led to an increase in Oncorhynchus masou (masu salmon) further upstream and a decrease in Salvelinus malma (Dolly Varden trout) and Noemacheilus barbatus toni (Siberian stone loach). These population changes indicated a change towards the balance of the ecosystem as it was before the dam was constructed. However, these findings are complicated by the fact that dam removal frequently leads to a large increase in sediment discharge immediately following removal, which negatively impacted the health of the aquatic ecosystems in the Kamo River study. The findings associated with the partial removal of a dam in Japan shows that the impacts of dam removal on ecosystems are many and varied and have lasting impacts on both the area around the dam and the societies that rely on these structures.
