POSTER PRESENTER: http://tinyurl.com/2024WSC-Finzel CO-AUTHORS: Jason Bried, Suneeti Jog, and David Zaya, Illinois Natural History Survey TITLE: Indicator species of floristic quality in Illinois wetlands: Success story or a textbook preconception? ABSTRACT: Wetland assessment has become increasingly imperative considering widespread wetland degradation coupled with the implications of the recent Sackett vs. US Environmental Protection Agency decision issued by the US Supreme Court. While traditional wetland assessment in Illinois relies on expertise-intensive, taxonomically-demanding methods like Floristic Quality Assessment, recent endeavors elsewhere have cautiously recommended using indicator plant species to identify high floristic quality wetlands and prioritize their conservation value. As a result, we chose to test candidate plant indicators for high as well as low floristic quality wetlands with larger datasets, more specific habitat categories, and geographic stratification. We considered candidate indicators as singleton species as well as pairs and triplets. Candidate plant indicators were generated using Indicator Value analysis with a subset of training data; subsequently, we tested the candidates’ relative abundance, relative frequency, and false positive error using the remaining data. Indicators of low floristic quality sites were generated but did not perform reliably enough to be ecologically meaningful. Some candidate plant indicators of high floristic quality sites met our testing requirements, and the suite of candidates plant indicators varied within geographic habitat strata and between datasets. Some candidate indicators performed well in certain tests and failed in others. Overall, results are varied when using indicator species as a surrogate for FQA and caution should be exercised when attempting to approximate a multi-species index with a single indicator. If indicator species exist for high floristic quality wetlands, land managers and consultants should use them only conservatively and incorporate other assessment criteria. BIO: Matthew Finzel (they/he) is a senior scientific specialist in wetland plant ecology at the Illinois Natural History Survey and a 2nd Year master’s degree student in the University of Illinois’s Natural Resources and Environmental Sciences program. Matthew’s research interests include wetland bioassessment, ecological restoration, rare plant conservation ecology, citizen science, and field botany collections.