Minnesota wetlands are healthy overall, but suffering in some regions

Contact: Mary Connor, 651-757-2629

St. Paul, Minn. — As Minnesota’s 2015 waterfowl hunting season begins on Saturday, the Minnesota Pollution Control Agency (MPCA) is releasing two reports on the health of wetlands around the state. The health of a wetland’s vegetation can impact its quality as a habitat for ducks, geese, insects and other animals.

The two reports — Status and trends of wetlands in Minnesota — Depressional Wetland Quality Assessment (2007–2012) and Status and Trends of Wetlands in Minnesota — Vegetation Quality Baseline — look at the quality of vegetation in the more than 10 million acres of wetlands in Minnesota. The first report covers the “prairie pothole” marshes and ponds found in northwestern, central and south-southwestern Minnesota, whose quality has remained stable since they were last studied. The latter is the first study undertaken to assess the vegetative health of all Minnesota’s wetlands. Overall, wetlands in the state are healthy, though the quality varies dramatically by region.

Vegetation quality is exceptional in approximately 49 percent of the state’s wetlands. Exceptional quality is defined as plant diversity and health similar to sites that haven’t been affected by development, agriculture and other human activities. Thirty-three percent of wetlands are in fair or poor condition, in which vegetation is degraded and native plants are being replaced by non-native invasive plants.

Although Minnesota wetlands can claim good health in total, that overall status masks some regional issues. Around 75 percent of the state’s wetlands are in the north-central and northeast regions, where less development and lighter land uses have allowed wetlands to thrive. However, 80 percent of the remaining wetlands — in the central, southern and western regions — have degraded vegetation quality, particularly from invasive plant species, such as cattails and reed canary grass. Aquatic invertebrates (insects, snails, leeches and crustaceans) are not suffering as much: invertebrate communities in 57 percent of these regions’ marshes and ponds are in fair or poor condition.

“Excess phosphorus and nitrogen levels from runoff pose a significant threat to the biological integrity of these wetlands,” says Michael Bourdaghs, MPCA research scientist and author of the report on overall vegetation quality.

Because Minnesota has lost roughly half of its wetlands since European settlement, much of the focus on wetlands has addressed maintaining or increasing the amount of wetland acreage. But wetland quality affects the way wetlands are able to support watershed health and serve as animal habitat, and is an important aspect of meeting state and federal policy goals. The MPCA is recommending a greater emphasis on wetland protection to promote the quality and biological diversity of the state’s wetlands.

For more information, visit the Wetland Quality Status and Trends Monitoring webpage.