The Effects of an Invasive Crayfish on the Aquatic Macroinvertebrate Community in an Ozark Stream
Freeland-Riggert, Brandye T.
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Introductions of non-native species into aquatic ecosystems have been well documented, including invasions of crayfish species which can negatively affect multiple trophic levels. Macroinvertebrates make up part of crayfish diets, yet little is known about the impacts of these introductions on macroinvertebrate communities. Orconectes (Procericambarus) hylas (Faxon) (the woodland crayfish) has been introduced into the St. Francis River watershed in southeast Missouri and displaced populations of native crayfish. The effects of this introduced crayfish on macroinvertebrate community composition was investigated in a fourth order Ozark stream at two locations, one with the presence of O. hylas and one without. Significant differences were found in five benthic macroinvertebrate community metric categories (richness, composition, dominance/diversity, functional feeding groups, and tolerance) between sites across four sampling periods. The invaded site had significantly higher Elmidae (riffle beetle) abundance, and significantly lower total taxa richness, Chironomidae (midge) richness and Chironomidae abundance.