TEMPORAL CHANGES in Fish Community STRUCTURE
Observed changes in stream fish communities over time can be related to environmental conditions, thereby informing conservation and management of freshwater resources.
We are sampling fish assemblages in streams and springs in and around Arnold Air Force Base in middle Tennessee. Using collected data, we will assess the biotic integrity of sampled streams and examine temporal trajectories of change within the communities. Additionally, we are sampling springs to determine if the distribution of introduced western mosquitofish (Gambusia affinis) has expanded over time in these habitats, which would limit the potential of the habitats as introduction sites for the threatened Barrens topminnow (Fundulus julisia).
FUnctional role of migratory fresHWATER FISHES
Many freshwater fishes move between multiple habitats during their life cycle, and these movements can result in the redistribution of nutrients and energy.
We are working with buffalo (Ictiobus spp.) migrations that occur every spring in Citico Creek in eastern Tennessee. Given the relatively low background nutrient levels in Citico Creek, and the fact that the buffalo migrations take place at a time when aquatic primary production is ramping up, we hypothesize that the migrations transport substantial amounts of nitrogen and phosphorus to Citico Creek. We are quantifying these nutrient contributions that occur via three pathways: eggs, excretion, and carcasses, and then examining ecosystem responses to the buffalo-derived nutrients.
Click the link below to see drone footage we captured during the 2019 buffalo migration in April. We hope to use the approach to enable estimates of the number of migrating individuals - stay tuned!
NATIVE FISH CONSERVATION
The Southeastern US harbors the highest levels of freshwater fish diversity of any temperate region in the world, and effective conservation of numerous small-bodied, non-game fishes in the region will be facilitated by studies providing more information about the ecology of these species.
We are working on the conservation of striated darter (Etheostoma striatulum), a member of the barcheek darter group that is found only in the middle and upper reaches of the Duck River watershed in middle Tennessee. We are visiting sites last surveyed over a decade ago to obtain an updated understanding of the distribution and abundance of the species. Additionally, we are examining the possibility that juvenile and adult individuals use different types of habitats, which would influence the extent and nature of habitat types that need to be provided to ensure continued persistence of the species.
MODELING STREAM FISH RESPONSE TO ENVIRONMENTAL CHANGE
Freshwater ecosystems and the organisms inhabiting them are facing unprecedented changes, and models that relate population and community responses to these changes will enable managers and conservation practitioners to better predict responses to different environmental changes.
We are collaborating with researchers at the University of Georgia River Basin Center to develop quantitative models that relate stream fish responses to hydrologic variability in the Apalachicola-Chattahoochee-Flint River Basin that covers parts of Georgia, Alabama, and Florida. Once developed, the models can be used to predict population- and community-level responses to specific hydrologic patterns that could be produced by climatic or management-induced changes.