The Prairie Pothole Region

The Prairie Pothole Region is an ecological treasure that was historically one of the largest grassland-wetland ecosystems on earth.

Photo: Casey Stemler

Prairie Pothole Joint Venture

The Prairie Pothole Joint Venture (PPJV) includes one-third (100,000 square miles) of North America’s Prairie Pothole Region (PPR), covering portions of Montana, North Dakota, South Dakota, Minnesota, and Iowa. The remaining 200,000 square miles is located in the Canadian provinces of Manitoba, Saskatchewan, and Alberta. Its uniqueness lies in the millions of depressional wetlands that constitute one of the richest wetland systems in the world. These glacially formed “prairie potholes” and their surrounding grasslands are highly productive and provide a wide array of ecosystem services that benefit birds, other wildlife, and people.

The Prairie Pothole Region is a vast area of depressional wetlands straddling the border of the United States and Canada that incorporates two Joint Ventures: the Prairie Habitat JV and the Prairie Pothole JV.

Habitats

The PPR is one of the most important migratory bird habitats in the Western Hemisphere and is the backbone of North America’s “duck factory,” providing critical habitat for many wetland- and grassland-dependent migratory birds.

The Prairie Pothole Region (PPR) of North America is a unique and extraordinary ecosystem. After the retreat of the glaciers 10,000 years ago, the PPR consisted of a vast grassland ecosystem dotted with millions of shallow wetlands of unparalleled density and productivity. These “prairie potholes” and the surrounding grasslands provide excellent habitat for an incredible diversity of wildlife. The PPR is one of the most important migratory bird habitats in the Western Hemisphere and is the backbone of North America’s “duck factory,” providing critical habitat for many wetland- and grassland-dependent migratory birds.

What’s a Pothole? A depressional wetland formed by a glacier.

Once one of the largest grassland-wetland ecosystems on earth, the PPR is now dominated by cropland. Changing crop types across the region have introduced more intensive cropping systems and expansion into areas previously considered unfit for row crop production. Demand for biofuels adds to the pressure for conversion of grasslands to cropland. Oil and gas development is growing rapidly in portions of the PPR and expanding wind energy development also has potential to impact the landscape. These changes in land use have been detrimental to migratory birds, as most grassland-dependent species do poorly on cropland relative to undisturbed land.

Lostwood: the difference in a single year

Lostwood 2008

Lostwood 2009

Two photos of the Lostwood four-square-mile survey plot depict the difference one year can make in the prairies, where the climatic conditions are highly variable. Protecting the remaining wetlands and grasslands and restoring lost and degraded habitats will allow this dynamic nature to persist and our priority species to thrive.

Globally, grasslands are the most human-altered biome with the highest risk of biome extinction. Today, more than half of the historic wetlands are gone and nearly 70% of the original grasslands support crop production. Current grassland loss rates in the northern Great Plains are occurring five times faster than grasslands can be protected. Only 20% of the grassland in the U.S. PPR is protected as of 2021, which equates to just 6% of historic grass area. Additionally, only 34% of the wetlands are protected. Many wetlands have been drained or degraded, and the loss of native prairie has been extensive. Despite these losses, millions of wetlands and large tracts of native prairie still remain.

Birds

The PPR is envisioned as a place where abundant populations of wetland and grassland birds can be sustained in perpetuity for the benefit of all people who enjoy these species.

As an “all bird” Joint Venture, the PPJV is committed to addressing the conservation needs of all avian species that use the U.S. Prairie Pothole Region (PPR). This is a daunting task given the diversity of bird species and landscapes and the variability in understanding of factors that influence population change. The PPJV uses a strategic, science-based approach to conservation among four bird groups: waterfowl, shorebirds, waterbirds, and landbirds.

The historic PPR was a mecca for breeding waterfowl unparalleled anywhere else in North America. Since the North American Waterfowl Management Plan (NAWMP) was first adopted nearly 30 years ago, the PPR of the U.S. and Canada has been recognized as the most critical region to breeding ducks in North America. The millions of wetlands that dot the PPR and its large areas of intact grassland make it one of the most unique and productive landscapes for waterfowl in the world.

Despite agricultural conversion of wetlands and grasslands, the region remains a national treasure for waterfowl. Ducks produced in the U.S. PPR are harvested in 49 states (the only exception being Hawaii) as well as Canada, Mexico, the Caribbean, and northern South America. In the late 2000s, when the entire U.S. PPR was wet, the region supported nearly 14 million ducks, and in a typical year is believed to sustain up to 10 million ducks.

The value of the U.S. PPR to birds goes far beyond waterfowl, providing breeding or migration stopover habitat for 36 of 50 shorebird species that regularly occur in the country. Wetlands provide habitat for at least 40 species of waterbirds such as terns and gulls, secretive marshbirds like rails and bitterns, and American white pelicans. These wetlands are critical for migrating waterfowl, shorebirds, and waterbirds, with waves of species passing through the region each spring and fall. Even though the region is at the northern edge of the country, it is a continental nexus for species migrating to and from the southern U.S., Mexico, Central America, and South America.

Priority Grassland Species

Large-scale conversion of grassland habitat to crop and energy production has contributed to grassland bird losses in North America, with populations declining faster than any other bird group over the last 40 years. The Northern Great Plains – including the PPR – has the highest diversity of grassland bird species on the continent, including four species of conservation concern due to ongoing population declines: Sprague’s pipit, Baird’s sparrow, thick-billed longspur (formerly McCown’s), and chestnut-collared longspur.

Sprague’s Pipit photo by John Carlson

Baird’s Sparrow photo by Jim Williams

Thick-billed Longspur photo by Scott Somershoe

Chestnut-collared Longspur photo by Scott Somershoe

Ecosystem Services

Abundant and diverse bird communities in the U.S. PPR provide society with a wide array of benefits.

In addition to providing habitat for a broad suite of wildlife species, prairie pothole wetlands and grasslands also provide a variety of ecological goods and services to the people living in the region and well beyond. Ecosystem services are the benefits to people from nature, including food, water purification, carbon sequestration, soil stabilization, recreation, cultural values, and hydrologic storage to reduce flood severity. The contribution of natural ecosystems to these benefits is rarely measured and quantified, but their value is becoming more apparent as human populations grow and demand for natural resources increases. While it is better to protect intact wetlands and grasslands, the restoration of degraded ones can restore some ecological functions.

Some of the most important ecosystem services that this region provides include the following:

Surface water storage and flows: Prairie wetlands store water during spring runoff and following prolonged precipitation events. Slowing runoff rates reduces economic losses from flood damage to structures such as roads and houses. Wetland losses in the PPR contribute to increased flooding along the Mississippi River, hundreds of miles away.
Groundwater recharge: Surface water stored in prairie potholes interacts with groundwater in a variety of ways. Potholes can be both areas of local recharge to groundwater and areas where groundwater discharges to the surface. They can also be important for recharging regional aquifers.
Controls for contaminants: Prairie potholes often receive substantial inputs of chemicals, nutrients, and sediments from agricultural or industrial operations. In some cases, wetlands can break down undesirable chemicals into less toxic by-products. Excess nutrients are incorporated into wetland flora and fauna, improving downstream water quality. Wetlands reduce peak river flows, allowing sediments to settle out of the water column.
Greenhouse gas flux: PPR wetlands and grasslands are known to be important carbon stores. Restoration of wetlands and grasslands within the PPR can help mitigate greenhouse gas emissions and increase carbon storage capacity in the region.