By Tom Landwehr
Posted Sunday, October 3, 2004
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Once, the Prairie Pothole Region (PPR), with its expansive prairies interspersed with many small, shallow wetlands, was referred to as the "duck factory." Landscape conditions have changed, but the moniker hasn't. This region is the primary breeding grounds for about 50 percent of North America's ducks.
The Minnesota Department of Natural Resources (Department) recently completed an action plan to address the quality decline of wetlands. One element of the plan calls for the enhancement of shallow lakes, especially those specifically designated for wildlife management, by better managing water levels to encourage plant growth. A large portion of the U.S. PPR covers the western half of Minnesota. Unfortunately for waterfowl, this area has lost about 90 percent of its wetlands to development. And worse, the quality of many remaining wetlands, as well as rivers and streams, have been seriously degraded due to ditching, sediment transport, fish invasion, and high water levels.
The Minnesota Department of Natural Resources (Department) recently completed an action plan to address the quality decline of wetlands. One element of the plan calls for the enhancement of shallow lakes, especially those specifically designated for wildlife management, by better managing water levels to encourage plant growth.
One such body of water is Augusta Lake in southwestern Minnesota. For many years, this shallow, 500-acre lake has suffered from the ill effects of high water levels, turbid water, lack of vegetation, and invasive fish.
A concurrent concern in the State is the long-term decline of lesser scaup populations. Recent studies by Louisiana State University and Ducks Unlimited, Inc., suggest that the population decline may be exacerbated by poor conditions on spring-migration habitat in Minnesota and adjacent states.
"Poor condition" is defined as limited availability of aquatic invertebrates, a scaup staple and a fish favorite. The drainage of Minnesota farm fields into shallow lakes has dramatically increased the presence of fish and their ability to survive.
According to the research, hens arrive late on northern boreal Canada breeding grounds and are not in optimal body condition, most likely due to poor spring-migration habitat. The apparent results: delayed nest initiation, reduced nest success, and possibly lower hen survival.
Ducks Unlimited biologists have identified certain shallow lakes that can be improved for migrating scaup through more intensive water management and fish exclusion.
Augusta Lake is one of these. Ducks Unlimited and the Department began working together in 2002 to replace an outlet structure that would exclude fish and allow for scheduled drawdowns on the lake. In the summer of 2003, a new structure was in place.
A persistent summer drought did not allow water levels to reach full pool by the fall, but approximately 80 percent of the lake bed had water on it by October. The water depth in most areas was less than 2 feet, and the waterbirds loved it.
All fall, until ice covered the lake in late October, the basin was covered with migrating waterfowl and other wetland birds. The shallow water provided the food and security sought by these birds. Once the planned water level is achieved in 2004, and desirable plants have had a chance to grow, the lake will provide outstanding migration and breeding habitat.
Wildlife managers are anxiously awaiting the spring migration — lesser scaup should be able to get fat here!
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