Vast grasslands once covered much of North America. Settlement, agriculture, and development have reduced prairie habitats to a patchwork of isolated grasslands in a sea of croplands, roads, and cities. Loss of grasslands is detrimental to people as well as wildlife. Grasslands help reduce soil erosion caused by wind and water. They also filter chemicals, thus protecting our water supplies. Vegetation, such as grass, forbs, and shrubs, help trap snow and rain. This allows a more regulated flow of precipitation to seep into the ground, recharging water supplies. Grasslands also provide forage for livestock. Many wildlife species depend on grasslands for food, cover, and nesting sites.
Bowdoin's 8,325 acres of uplands are comprised of five major habitat types. The refuge's high percentage of native mixed-grass prairie (6,689 acres) is a unique feature of the station. Other upland types include inland saline flats, shelterbelts, shrub areas, and dense nesting cover (DNC). DNC is primarily made up of tame grasses and forbs such as wheat grass, sweet clover and alfalfa and is planted on areas that were once farmed to restore cover and nesting habitat for many species of prairie birds. Mixed-grass prairie has representatives of both tall-grass priaries and short-grass prairies. Here at Bowdoin NWR, needle-and-thread grass, western wheatgrass and blue grama are the dominant grass species.
It is important to protect wetlands, as they benefit people as well as wildlife. Wetlands can control erosion and prevent flooding by holding water and reducing runoff. They also recharge sub-surface water supplies and provide hay land in dry years. Wetlands provide crucial habitat for many types of wildlife including ducks, songbirds, and deer. More than half of the nation's wetlands have been lost to agricultural drainage since the 1800's.
Refuge wetlands total about 7,226 acres. Lake Bowdoin itself is 5,459 acres. Wetlands are classified as ephemeral, temporary, seasonal, semi-permanent, and permanent depending upon the length of time in which they hold water. Bowdoin NWR has all five wetland types. The wetlands arranged within and around the Refuge appear as a huge wetland complex for waterfowl and other wildlife searching for nesting, resting or feeding sites. Waterfowl in particular use every wetland type during different parts of the year. For example, mallards may use small temporary wetlands, sometimes referred to as pair ponds for mating, and then progress to larger, more open water like semi-permanent wetlands once ducklings are hatched. This behavior illustrates how every type of wetland is equally important for migratory bird success.
Wetland vegetation is the key to productive wetland habitat. Desirable emergent aquatic plant species include smart weed, spike rush and wild millet while desirable submergent aquatic plants include sago pondweed and widgeongrass. Aquatic vegetation not only provides food for waterfowl, but also shelter for aquatic invertebrates which many birds also eat.