Aquatic community monitoring at Effigy Mounds National Monument, 2008?2017

Abstract

Dousman Creek, located in northeastern Iowa, is a Class ?B? coldwater stream that supports a trout population and is listed among the Outstanding Iowa Waters (Iowa Department of Natural Resources 2010, 2016). The Heartland Inventory and Monitoring Network (Heartland Network) of the National Park Service (NPS) has been monitoring aquatic communities (fish and invertebrates) in Dousman Creek within Effigy Mounds National Monument (NM) since 2008. Corresponding physical habitat and water quality were also collected during biotic sampling. The objectives of this long-term monitoring program are to assess the status and trends in the biotic stream community and relate these trends to environmental variables. The purpose of this report is to summarize the baseline aquatic community data collected during three sampling events conducted from 2008 to 2017. The fish community was dominated by the intolerant cool/cold-water species Brown trout (Salmo trutta) and Mottled sculpin (Cottus bairdii) in 2008, while more tolerant white sucker (Catostomus comersonii) and Johnny darter (Etheostoma nigrum) were most abundant in 2014. During 2017, fish community composition was more evenly distributed among species present. Benthic invertebrate samples were dominated by the moderately intolerant mayfly genus Pseudocloeon and blackfly genus Simulium in 2008 and 2014, while the invertebrate samples in 2017 were dominated primarily by a tolerant, mayfly taxa (Baetis) and Oligochaetes. The abundance of aquatic invertebrates in 2017 was more than ten times lower than invertebrate abundance in 2008 and 2014. Water quality data collected by the Heartland Network did not indicate any of the five parameters (temperature, dissolved oxygen, pH, specific conductance, or turbidity) exceeded the Iowa Department of Natural Resources water quality standards, however the number of hourly measurements were low (4?20 measurements) depending on year sampled. Three years of data are currently insufficient to fully characterize the stream integrity of Dousman Creek based on fish and invertebrate communities. Continued long-term monitoring of Dousman Creek will allow for better assessment of the biotic integrity and overall quality of the stream.