Prairie Potholes
These freshwater marshes are found in the upper Midwestern prairies, especially the Dakotas and Minnesota. Depressions that were created by retreating glaciers about 10,000 years ago;, they fill with water during spring, providing important habitat for waterfowl and many other species. Indeed, the Prairie Pothole Region is often called America’s “duck factory” since around half of the continent’s ducks spend at least part of the year there. The prairie potholes are an important water source, and they help recharge underground aquifers.