Abstract

Lake Erie, one of the 5 Laurentian Great Lakes, suffers from harmful algal blooms in its western basin that are associated with phosphorus (P) loading from the Maumee River Watershed (MRW), United States. Additionally, certain waterfowl populations in the MRW have declined significantly in recent decades. Wetlands provide ecosystem services such as reducing P pollution and providing habitat for waterbirds, but these objectives are often treated separately. Simple tools are needed in this region for improved wetland restoration for meeting the dual goals of providing waterfowl habitat and improving water quality through P retention via design and management. This research identified 2 main objectives in support of these goals: 1) create a parsimonious model that assesses wetland P retention and waterfowl habitat suitability simultaneously, and 2) create a spreadsheet tool to implement the model to identify water management and design approaches that improve P retention and waterfowl habitat suitability. A total of 249 observations of wetland P fluxes, with agricultural runoff as the primary pollutant of interest, were input into a first-order pollutant removal model to generate P retention estimates. Waterbird habitat suitability was assessed based on preferred foraging depths. Results show that active, dynamic management of water depth can help reduce tradeoffs between wetland objectives and that larger wetlands (at least 2% – 7% of subbasin area) tend to outperform smaller wetlands in meeting both objectives.

Keywords: Eutrophication, Nutrients, Waterfowl, Phosphorus, Waterbirds