You are here:
Spatial comparison of eDNA vs. physical fish data from a complex freshwater estuary
Citation:
Trebitz, A., C. Hatzenbuhler, J. Hoffman, J. Barge, G. Peterson, E. Pilgrim, L. Chadderton, AND A. Tucker. Spatial comparison of eDNA vs. physical fish data from a complex freshwater estuary. Upper Midwest Invasive Species Virtual Conference, Duluth, MN, November 02 - 06, 2020. https://doi.org/10.23645/epacomptox.13122815
Impact/Purpose:
The study described in this poster represents a collaboration with staff of the Nature Conservancy towards refining early detection monitoring for aquatic invasive species. This work was conducted under SSWR research area 3.01A-2.1, and builds on previous EPA/ORD case studies concerning early-detection monitoring strategies. Outcomes from this research will include development of more refined and robust sampling strategies for non-native species in different coastal systems across the Great Lakes as well as advancement of DNA-based tools for conducting such monitoring.
Description:
Analysis of environmental DNA (eDNA) offers a means of detecting target species and characterizing biological communities without having to collect the organisms themselves. The potential for eDNA to disperse widely from the organisms that generated it is a major reason for its appeal as a sampling target, but also raises important questions concerning what can be expected of spatial patterns arising from eDNA data relative to physical catch data. We explore these questions for fish communities in the St. Louis River Estuary -- a hydrologically open and spatially complex freshwater estuary of Lake Superior -- via the comparison of eDNA to physical survey data (~ 240 samples each) for 41 shared fish species. Comparisons among 6 broad spatial zones showed eDNA generally outperforming physical surveys in the early but not the late season, with details including a spatial gradient across zones and differences among the fish guilds involved. Four non-indigenous species were better detected with eDNA surveys, but two others were better detected with physical surveys. NMDS ordinations showed more spatial differentiation in fish structure in the late than early season for both survey types, but with relationships to fetch and vegetation more pronounced for physical surveys. GIS-based ‘hot-spot’ analyses showed much more pronounced spatial clumping of many fish species with physical surveys than with eDNA data. eDNA surveys provides a sensitive tool for establishing species presence at the system scale but tends to obscure spatial distribution information that is relevant to location-specific restoration and management actions.
URLs/Downloads:
DOI: Spatial comparison of eDNA vs. physical fish data from a complex freshwater estuary