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SFS Annual Meeting

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AQUATIC INSECT EMERGENCE PRODUCTION FROM HYDROLOGICALLY ALTERED SECTIONS OF A LOW GRADIENT MIDWESTERN RIVER

Stream communities and the ecological processes they govern, are influenced by the physical template of lotic systems, particularly hydrology. The Cache River in southern Illinois has undergone several hydrologic alterations over the past century. In particular, construction of a ditch to the Ohio River dramatically changed hydrology and divided it into the upper Cache River (UCR) and lower Cache River (LCR). This resulted in increased water velocities and erosion in the UCR, and decreased flows and low dissolved oxygen in the LCR. To examine how hydrology influenced stream communities and associated ecosystem processes in the two sections, we sampled adult insect emergence in the UCR and LCR during summer through winter of 2017. There was no significant difference in the diversity of emerging insects between the UCR and LCR (p = 0.2). However, abundance (p < 0.0001), richness (p < 0.0001), and production (p < 0.0001) were all significantly higher in the UCR. This ongoing study will assess how hydrology in each river section ultimately affects ecological subsidies and riparian predators through changes in the availability and nutritional value of emerging adult aquatic insects.

Katie Heiden (Primary Presenter/Author), Southern Illinois University, Katie.heiden@siu.edu;


Matt Whiles (Co-Presenter/Co-Author), University of Florida, mwhiles@zoology.siu.edu;