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Invasive Ringed Crayfish: Understanding occurrence patterns in the southwest Ozark Highlands

Mouser, Joshua
Invasive species are one of the largest drivers of declining biodiversity in stream ecosystems worldwide; however, factors explaining successful invasions are poorly understood. Ringed Crayfish Orconectes neglectus is non-native in many areas and its success as an invader has been hypothesized to be due to biotic factors (i.e., competition), but this has never been confirmed. However, I hypothesized persistence of Ringed Crayfish may instead be due to abiotic factors. Therefore, my objective was to identify environmental factors related to the relative abundance of the Ringed Crayfish in streams of the southwest Ozark Highlands where it is native. Crayfish were collected from 14 streams using tow-barge electrofishing and kick-seining. I used multiple linear regression to examine the relationship between landscape factors (e.g., geology, percent agriculture, soil texture, distance to impoundment, catchment size, stream segment drainage, water temperature) and the relative abundance of Ringed Crayfish within its native range. My results indicated that shale lithology and possibly warm water temperatures are negatively related to relative abundance of Ringed Crayfish. This research aids managers in understanding what abiotic conditions may foster or inhibit the successful invasion of Ringed Crayfish outside their native range.