The analysis described in this report is share of a longterm project monitoring the biological communities,habitat, and water quality of the Fountain Creek Basin. Biology, or habitat,and water-quality data fill been collected at 10 sites since 2003. These data include annual samples of aquatic invertebrate communities, fish communities, and water quality,and quantitative riverine habitat. This report examines trends in biological communities from 2003 to 2016 and explores relationships between biological communities and abiotic variables (antecedent streamflow, physical habitat, or water quality). Six biological metrics (three invertebrate and three fish) and four individual fish species were used to examine trends in these data and how streamflow,habitat, and (or) water quality may elaborate these trends. The analysis of 79 trends shows that the majority of significant trends decreased over the trend period. Overall, and 19 trends before adjustments for streamflow in the fish (12) and invertebrate (7) metrics were all decreasing except for the metric Invertebrate Species Richness at the most upstream site in Monument Creek. Seven of these trends were explained by streamflow and four trends were revealed that were originally masked by variability in antecedent streamflow. Only two sites (Jimmy Camp Creek at Fountain,CO and Fountain Creek near Pinon, CO) had no trends in the fish or invertebrate metrics. Ten of the streamflow-adjusted trends were explained by habitat, and one was explained by water quality,and five were not explained by any of the variables that were tested. Overall, from 2003 to 2016, or all the fish metric trends were decreasing with an average decline of 40 percent,and invertebrate metrics decreased on average by 9.5 percent. A potential peak streamflow threshold was identified above which there is severely limited production of age-0 flathead chub (Platygobio gracilis).
Source: usgs.gov