Distribution of invasive scud, Apocorophium lacustre (Vanhoffen, 1911) in the Illinois Waterway, USA: Do habitat and water quality variables influence spatial distribution and relative abundance?

Study area and sampling distribution map showing benthic amphipod rock bag sampling effort in 2020–2021 across the Illinois Waterway. Black squares represent the dams at the downstream end of the pools/reaches of the Illinois Waterway. The Alton Pool ends at the confluence of the Illinois and Mississippi rivers and does not have a dam. The inset map provides a detailed look of the waterbodies comprising the Chicago Area Waterway System and lower Des Plaines River, including the current invasion front of Apocorophium lacustre based on this study.