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Research Question: Is Chaoborus americanus a useful bioindicator of contemporary and historical fish absence in Minnesota’s shallow lakes? The phantom midge Chaoborus americanus (Diptera: Chaoboridae) is restricted to fishless habitats due to their vulnerability to fish predation (Von Ende, 1979, Schilling et al. 2009). Their chitinous mandibles are preserved in pond sediments, making this species an excellent bioindicator of historical fish absence in water bodies with unknown fish colonization history (Lamontagne and Schindler, 1994; Schilling et al. 2008). Our research is part of a larger project using paleolimnological techniques to understand historical regime shifts (from clear to turbid states) in shallow lakes in the Prairie Pothole Region (PPR) of Minnesota (Hobbs et al. 2016). As part of the larger study, fish and macroinvertebrate communities were sampled and sediment cores were collected from a large set of study lakes in the PPR (Hobbs et al. 2016). We are interested in examining the role that fish colonization/extinction has played in triggering regime shifts in shallow lakes. Our current research objective is to test methods for detecting fish presence/absence developed in Maine (Schilling et al. 2008, 2009) to see if they are applicable to lakes in the PPR.
Minnesota, Lakes, fish, freshwater, midge
Kundel, Holly and Natrop, Isabelle, "Phantom midge mandibles in lake sediments as bioindicators of historic fish absence in Minnesota’s shallow lakes" (2018). Zyzzogeton Posters. 10.