Poster Details
THE ROLE OF STREAM NETWORK GEOMETRY AND CLIMATE ON THE SPATIAL EXTENT OF AQUATIC-DERIVED RESOURCES IN TERRESTRIAL ENVIRONMENTS
The effects of emergent aquatic insect subsidies are pronounced at the water’s edge, yet less is known about the extent these resources permeate into upland environments: here we assessed the relative role of stream network geometry and climate. We estimated the area at which aquatic derived resources could be detected at 25% of the value at the stream bank (i.e. “stream signature”), for ~1,600 complete stream networks across the contiguous US. We characterized the network geometry with Horton’s Laws and drainage diameter and density and compiled several hydroclimate variables, including mean annual precipitation and estimated flow. Given high in-stream productivity, we found up to 36% of the watershed could be subjected to a 25% stream signature and that the spatial extent was strongly related to stream network density. This work supplements other theoretical developments with more realistic stream networks and demonstrates the utility of a nationally consistent dataset in assessing aquatic-terrestrial resource exchange across broad spatial extents. Further, it provides a spatially explicit prediction of aquatic resource flux which can be tested empirically and improved.
Darin Kopp (Primary Presenter/Author), U.S. Environmental Protection Agency, Kopp.Darin@epa.gov;
Darin Kopp earned a BS in biology and environmental science from DePaul University, a MS in wildlife science from New Mexico State University and a PhD in ecology and evolutionary biology from the University of Oklahoma. He has expertise in ecological modeling and data synthesis and his research typically focuses on understanding biological patterns at regional, continental and global scales. For his dissertation he focused on quantifying the potential redistribution of materials and energy from streams and rivers to adjacent terrestrial ecosystems using existing geospatial and biomonitoring datasets for the contiguous United States. After completing his PhD, he received an ORISE Postdoctoral Research Fellowship with the US Environmental Protection Agency’s Pacific Ecological Systems Division to investigate methods to improve biological assessments of streams and rivers at the national scale. In collaboration with several principal investigators from the National Aquatic Resource Surveys, his is using multi-species distribution models for aquatic benthic macroinvertebrates and fish to quantify geographic variation in taxon-specific relationships with environmental gradients that are commonly altered by anthropogenic activities.
Daniel Allen ( Co-Presenter/Co-Author), The Pennsylvania State University, dca5269@psu.edu;