Assessing Faunal Recovery in a Headwater Stream

Science Center Objects

A catastrophic fish-kill in a small tributary stream of the Etowah River system (Dawson County, Georgia) has created the opportunity to assess faunal recovery, including recolonization by a federally-listed fish species (the Cherokee darter Etheostoma scotti).  Fishes are expected to recolonize Flat Creek by moving upstream from downstream sources.  In particular, Flat Creek flows into a larger stream that harbors a diverse assemblage of native fishes including Cherokee darters.  However, a culvert built in Flat Creek the mid-2000’s to accommodate a new road crossing is anticipated to impede upstream movement by fishes and potentially other aquatic fauna.  Therefore, this work will assess and compare faunal recovery in Flat Creek upstream and downstream from the culvert approximately one year following the fish kill (which occurred in March 2018).

The Challenge: Information on the status of fishes is important to the US Fish and Wildlife Service and GA Department of Natural Resources.  Moreover, this event provides an opportunity to assess the effects of a potential barrier to fish movement on aquatic faunal recovery following catastrophic losses.  Chemical spills and similar catastrophes commonly occur in headwater streams where road-crossings also commonly pose potential barriers to faunal recovery.  Results from Flat Creek will thus have broader relevance for understanding the interactive threats of stochastic catastrophes and instream barriers to fish movement.

The Science: The USGS Principal Investigator, FWS Program Officers, and collaborators from the University of Georgia have quantified habitat conditions and sampled aquatic organisms at selected sites above and below the Flat Creek crossing culvert in Summer 2018 (following the spill), and April, July and October 2019.  We have targeted fishes, sampled using a seine through reaches up to 200 m in length, and amphibians, crayfishes, and aquatic insects. 

The Future: To date, a total of 11 fish species have been recorded in Flat Creek downstream from the perched culvert, only three of which have also been recorded upstream of the culvert.  The 11 taxa that have recolonized downstream portions of the stream represent a subset of the total taxa known to have inhabited the stream prior to the fish kill. Final analysis of these data will examine fish-habitat associations and fish length data for recolonizing species, and identify factors potentially limiting faunal recovery.  The data collected in this project will provide a baseline for future samples in this stream, and for estimating resilience of headwater stream populations of fish species of concern when inevitable catastrophic events occur.