The Influence of Drought on Flow-Ecology Relationships in Ozark Highland Streams

Drought and summer drying can have strong effects on abiotic and biotic aspects of stream ecosystems. We examined flow-ecology relationships in the Ozark Highlands over two years with contrasting environmental conditions, a drought year (2012) and a flood year (2013).  We examined metrics of community structure in fish, crayfish and macroinvertebrates using predictor variables incorporating hydrology, habitat, geomorphology, and water quality.  We found that hydrology was an important variable influencing community structure, but often less important than other types of environmental variables, especially in a drought year.  We found substantial between-year variation in flow-ecology relationships.  Ecological responses that we observed differed significantly between drought and flood years, and this highlights the importance of understanding temporal variation in flow-ecology relationships for resource planning.