Assessing Changes in Fish Traits and Water Quality in a Large Great Plains River

Anthropogenic changes to riverine systems are pervasive and multifaceted with flow modifications often a driver of changing inchannel conditions. Climate and land-use change contribute to inchannel alterations by changing runoff patterns and constituents delivered to stream ecosystems.  These threats combined create a difficult situation for managing and conserving stream organisms. The objectives of this study were to use existing data to assess changes in water-quality constituents over time and assess how those changes have impacted the persistence of stream-fish traits.  Water quality was estimated on a daily basis using LOADEST, a USGS regression analysis tool for estimating contaminant loads in rivers where adequate samples exist. We performed trend analyses on ecologically-relevant water-quality variables (e.g., dissolved chloride, suspended sediment) at gaged locations on a large Great Plains river. There was a significant relationship between flow weighted constituent concentrations or mean annual constituent values and time suggesting increases in chlorides, pH, and stream temperature at the upstream portion of the study site and decreases in suspended sediment and chlorides at the most downstream site. We relate fish traits to changes in water quality to make predictions about species sensitivity with increasing alterations.