Citation:

Yeardley, R., M. Mills, AND J. Lazorchak. Effects of Spatial Variability of Macroinvertebrate Communities on Assessment of Remediation and Restoration Efforts at Great Lakes Area of Concern (AOC) Sites. 2023 SETAC North America Annual Meeting, Louisville, KY, November 12 - 16, 2023.

Impact/Purpose:

ORD plays a vital role in the process of remediation and restoration of Great Lakes Areas of Concern (AOCs) by refining, developing, and giving guidance on methods, metrics, and models to assess the effectiveness of restoration outcomes. This presentation will communicate to scientific community and our state and federal partners ORD's efforts to refine bioassessment tools to evaluate the effectiveness of remedies which have the potential to improve the human health, environment, and economies of AOC communities. As AOCs tend to be highly populated, these remedies can potentially have positive impacts on the lives of large numbers of people. 

Description:

The U.S. EPA’s Office of Research and Development (ORD), in working with its multiple state and federal partners, is tasked with helping to determine if conditions have improved post-remediation and restoration at Great Lakes AOC sites.  Environmental agencies of the Great Lakes states have long used macroinvertebrate community metrics and indices in bioassessment, and more recently for delisting of Beneficial Use Impairments (BUIs) at AOCs.  Spatial variability will affect the ability to detect community differences pre- and post-remediation and restoration. Though duplicate samples of media for chemical analyses have long been collected as part of bioassessment efforts, it is not as common to collect duplicate community samples, especially with long-term deployment of artificial substrate samplers.  Since 2020, ORD has been deploying duplicate moorings at AOC sites to assess spatial variability in macroinvertebrate communities and how that will affect the ability to detect changes. We assessed small-scale spatial variability from community data from duplicate moorings (each with multiple Hester-Dendy (HD) samplers), deployed and retrieved from 17 Stations at 9 Sites (Ottawa River, Otter Creek, Swan Creek, Lower Maumee River, Pickle Pond, Loons Foot Lake, Erie Pier Pond, Clough Pond, Ashtabula River), located at 3 AOCs (Maumee River (Toledo, OH), St. Louis River (Duluth, MN, Ashtabula River (Ashtabula, OH)). Using a suite of structural and functional metrics and indices, we compared metrics derived from retrieved communities by examining the relative percent differences (RPD) of these metrics for the pairs of samples from all stations from all sites.  Variability was metric/index dependent.  For example, the common metrics, total taxa richness and percent dominant taxon, had RPDs of 15% and 24% respectively.  The RPD for abundance/ density was 41%. The lowest RPDs were those of metrics/ indices that incorporated tolerance values, the Hilsenhoff Biotic Index (3.3% ) and the mean tolerance value (3.2% ).  At Ohio AOCs, 2 versions of HD samplers were deployed, an ORD version and an Ohio EPA version. No significant difference (paired t-tests, p ≤ 0.05) was seen for any metric or index when RPDs from both types of samplers were compared.  Multivariate analyses will also be presented as another line of analysis to compare similarity of communities retrieved by the duplicate moorings. 

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