A report released July 1 by the U.S. Fish and Wildlife Service (FWS), Status and Trends of Prairie Wetlands in the United States, 1997-2009, estimates that the total wetland loss in the Prairie Pothole Region between 1997 and 2009 was 74,340 acres, according to the Wildlife Management Institute. This amounts to an average net loss of 6,200 acres of wetlands per year. However, the report notes that emergent wetlands (emergent marshes and farmed wetlands) declined by an estimated 95,340 acres and shrub wetlands also declined by 46,080 acres. These losses were offset by the increase of 61,280 acres in forested wetlands and the 5,800 acres of new open water ponds over the 12-year period.

"Extreme weather patterns, rising agricultural commodity prices and oil and gas development are threatening millions of acres of prairie wetlands, putting further pressure on the most valuable breeding area for ducks in the Americas," said FWS Director Dan Ashe. "This report highlights the need for continued vigilance in monitoring and protecting the Prairie Pothole Region to ensure it remains healthy for waterfowl for generations to come."

According to the report, in 2009 there were an estimated 6.43 million acres of wetlands (6.7 percent of the total surface area) in the Prairie Pothole Region (PPR) that is located in parts of Montana, North Dakota, South Dakota Minnesota and Iowa. The current wetland acreage is a 61 percent reduction from the nearly 17 million acres of wetlands that were estimated in the region in the middle of the 19^th century. Even with the loss, the PPR contains about 5.8 percent of all wetlands in the conterminous United States.

Emergent wetlands make up about 87.7 percent of the total wetland area and 93 percent of all wetland basins in the PPR. However, the number of emergent wetland acres lost to agriculture and development accounted for 39 percent of all losses; of the 107,000 wetland basins lost in the region during the study period, 96 percent were classified as temporary emergent wetlands. These emergent wetlands are being converted to deepwater habitats or being drained for agricultural purposes. According to the report, 40 percent of the emergent wetland losses were due to the expansion of deeper, more permanent water areas. The report notes the trend towards fewer individual wetlands that cover larger acreage (mean size of wetlands increased from 2.1 acres in 1983 to 3.2 acres in 2009) with longer periods of wetness.

In supporting materials, the FWS concluded: "Despite efforts to conserve and restore wetlands in the PPR these resources continue to decline in number, diversity and extent. This puts the future of wetlands and prairie ecosystems in general in flux depending upon climatic shifts in temperature and precipitation with the compounding influences of anthropogenic alterations to local and regional land use and hydrology. Long-term trends continue to change the complexion of prairie wetlands from one of diverse wetland sizes and types to fewer wetland basins characterized by longer periods of high water. Prolonged high water conditions are causing some small wetland basins that flooded and dried on an intermittent basis to move toward becoming larger, more permanent wetland/water basins."

In 2013, researchers from the Prairie Pothole Joint Venture (PPJV) released a peer-reviewed study in the Wildlife Society Bulletin that assessed the conversion rates of both wetlands and grasslands in the region. That study determined that when time is incorporated into the conservation planning process, seemingly small wetland and grassland annual loss rates become far greater challenges. With wetland loss rates ranging from 0.05 to 0.57 percent per year and grassland loss ranging from 0.4 to 1.3 percent, PPJV partners will not be able to keep up with the conversion. The authors determined that the partnership would not be able to reach their conservation goals unless greater funding is targeted towards conservation, landowner interest and acceptance of conservation programs remains high, and wetland and grassland loss rates are decreased through public policy (particularly agriculture programs) or other mechanisms.

The full FWS report and other information is available on the USFWS National Wetlands Inventory web site. (pmr & jas)