An Integrated Wetland Condition Index and Environmental Metric Framework for the Prairie Pothole Region

The USDA-NRCS Agricultural Conservation Easement Program (ACEP) assists landowners with protecting, restoring, and enhancing wetlands. Evaluating wetland conservation efforts is crucial for informing future management decisions. However, assessment frameworks vary across regions and among stakeholders. The Prairie Pothole Region is an ecologically unique landscape characterized by its abundance of wetlands that provide important ecosystem services. To evaluate wetlands enrolled in ACEP, I sampled forty-five semi-permanent wetlands in the Prairie Pothole Region from July – August 2023 and 2024. I selected and sampled twenty-six wetlands enrolled in ACEP. Nineteen additional wetlands not enrolled in ACEP were also sampled; these included nine wetlands that represented sites adjacent to or within agriculturally influenced areas (e.g., high impact sites), and ten wetlands selected from areas representing minimally disturbed sites (e.g., low impact sites) managed by federal or state agencies. Environmental data (sediment and water chemistry) and biological data (macroinvertebrates, fish, and cyanobacteria) were collected at each site. Candidate metrics were identified through an exploratory analysis using discriminant analysis to evaluate environmental variation. Out of seventy-four environmental variables included in this study, ten were retained in the analysis, consisting mainly of sediment chemistry metrics. These metrics successfully classified 89% of the wetlands as high impact and 80% as low impact. Out of ninety-one biological variables, only three were retained, two deriving from macroinvertebrate data and one from cyanobacteria density. Based on the biological metrics, classification accuracy was 75% for high impact wetlands and 70% for low impact wetlands. The biological variables retained were standardized to develop a Wetland Condition Index (WCI) used to score high impact, low impact, and ACEP wetlands from 0 to 100. WCI scores differed between high vs low impact wetlands and revealed that ACEP sites were statistically similar to low impact wetlands. By measuring the aquatic structure and function of wetlands, I developed an integrated framework for the Prairie Pothole Region that can facilitate an effective monitoring program for wetlands enrolled in ACEP.