Tuesday, February 16, 2010

Prairie Potholes

Prairie Potholes

Sweeping across five Midwestern states and four Canadian provinces, North America's prairie potholes are an important habitat and natural resource of the Great Plains grasslands.

American Black duck

As ancient glaciers retreated over 10,000 years ago, millions of shallow depressions were left in the earth. These round (like a 'pot') depressions often fill with snowmelt and water in the spring, especially in wetter years, creating valuable seasonal wetlands that support rich plant and animal life.

Many millions of ducks and other waterfowl come to the prairie pothole region every year to feed and breed.

Importance of Prairie Potholes to People

Prairie potholes are important natural resources for people as well as waterfowl. They provide valuable, but often under-appreciated, ecosystem services that help people commercially, ecologically and economically.

  • They serve as natural sponges that hold excess water that helps reduce the severity and risk of downstream flooding.
  • They recharge groundwater systems that supply water to farmlands and wells in the region.
  • The potholes also provide water and forage for livestock.
  • Birders, as well as hunters, use the prairie potholes region as a destination for finding birds.

White Pelican flying

Wildlife in the Prairie Potholes

The 64 million acres of the prairie potholes that are in the United States have 18 species of waterfowl, 96 species of songbirds, 36 species of waterbirds, 17 species of raptors and 5 species of upland game birds.

Waterfowl: The prairie pothole region is home to more than 50 percent of North American migratory waterfowl. Waterfowl breeding here include pintail, gadwall, blue-winged teal, shoveler, canvasback and redhead. Many other migratory birds--such as the snow goose, lesser scaup and wigeon--pass through the region on their way to or from the Arctic and other northern breeding grounds.

Grassland birds: Many grassland birds are also found in the region, such as the bobolink, sedge wren, Sprague's pipit, Baird's sparrow, and the increasingly rare grasshopper sparrow.

Waterbirds: The U.S. part of the potholes region provides habitat for 40 species of breeding waterbirds, such as American white pelicans, rails, and herons.

Shorebirds: The piping plover, American avocet and Wilson's phalarope are among the shorebirds that breed in the prairie potholes region. Other shorebirds such as the hudsonian godwit, American golden-Plover, white-rumped sandpiper and buff-breasted sandpiper pass through the potholes during their migration.

Threats to the Prairie Potholes

Agricultural Development

The Great Plains are known as America's breadbasket. But before the farmers arrived, the Great Plains were the most extensive grassland in the world, with about 100,000 acres of prairie pothole wetlands. Today, only a small fraction of the grasslands remain, in small, disconnected fragments and only 50 percent of the prairie pothole wetlands still exist. The wetlands that remain are surrounded by agricultural lands and impacted by agricultural chemicals and excess sediments and nutrients that run off agricultural lands and into the potholes.

Conserving the remaining prairie potholes is important not only to maintain waterfowl populations, but also to improve both surface and groundwater availability for agricultural purposes, including grazing and crop irrigation.

For many years, ranchers and farmers have been given incentives through programs such as the Wetland Reserve Program (WRP) and the Conservation Reserve Program (CRP) to set aside lands for conservation and to adopt new management practices that reduce their impacts on natural areas. However, in recent years, high prices have encouraged farmers to return CRP lands to agricultural use, such as growing crops for biofuels, putting the prairie potholes at increased risk.

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