Ecological biodiversity on Savannah River Site continues to thrive

Jennifer Gibbons,

Contact: J Vaun McArthur,

Researchers at the University of Georgia Savannah River Ecology Laboratory have recently followed up on a study originally conducted in the 1970s and found that one of the most ecologically diverse streams in the world has not been negatively impacted by three decades of Department of Energy continued operations.

The research, conducted by J Vaun McArthur, a senior scientist in SREL and the University of Georgia Odum School of Ecology, focused on the diversity and richness of caddisflies, an aquatic insect, in the Upper Three Runs Creek on the Savannah River Site. Results showed that the animal’s prevalence is equal to or greater than that found in a study in the 1970s, highlighting a coexistence of long-term energy technologies, development within Aiken County and the maintenance of high biological diversity over many years.

Upper Three Runs Creek is the most species-rich stream in North America and perhaps the world. Originating near Aiken, S.C., it has nearly two thirds of its channel flowing through the Savannah River Site. More than 30 years ago, John Morse of Clemson University made a yearlong collection of aquatic insects at various locations on UTRC, identifying its rich biodiversity. His studies identified more than 500 species of aquatic insects in UTRC. Aquatic insects live most of their lives as immatures in rivers or streams and emerge as adults to find mates, lay eggs and die, sometimes in as little as one day after coming out of the streams.

Three groups of aquatic insects—mayflies, stoneflies and caddisflies—are extremely sensitive to pollution and thus are good indicators of anthropogenic stresses and serve as environmental monitors. These three major groups are responsible for many of the stream functions that indicate a healthy stream, as they are the food of choice for many game fish. Included in the 1970s diversity reports were more than 120 species of caddisflies. Many streams in North America have fewer than 120 total species of insects in total. Scientists consider UTRC a national treasure and it was not known what, if any, changes had occurred over the past thirty years in the level of biodiversity.

Beginning in 2010, McArthur obtained funding from the USDOE Environmental Management section to resample the same locations and at approximately the same sampling intervals as the previous study to determine whether there had been any impact on the biological diversity of UTRC after 30 more years of SRS operations. Together with Morse, he supervised the collections, assisted by Zachary Burington, a master’s student at Clemson. This time, the focus was specific to the caddisfly species. The results show that the diversity and richness of the caddisflies is equal to or greater than that found thirty years ago. Indeed, there are new records for the State of South Carolina and the discovery of unique species, including a species usually restricted to mountain streams such as in the Appalachians. While the data for the caddisflies is encouraging, both mayflies and stoneflies are often more sensitive to environmental impacts. McArthur plans to continue the study and complete the identifications of the stoneflies and mayflies in the future. Since development and large-scale industrial activities often result in major environmental impacts, these preliminary data demonstrate that despite changes in mission and scope on the Savannah River Site over thirty years of operation, the health of UTRC has been maintained.

The Savannah River Ecology Laboratory is a research unit of the University of Georgia, located at the U.S. Department of Energy’s Savannah River Site in New Ellenton, S.C.

J Vaun McArthur is a broadly trained aquatic ecologist with expertise in macroinvertebrates and bacteria. He has studied rivers, lakes and estuaries and has published his studies in many top-tier journals. He is the author of the textbook Microbial Ecology: An Evolutionary Approach, published by Academic Press. He has been at UGA for nearly 27 years.