Prairie potholes Prairie potholes are saucer-shaped depressions formed by retreating glaciers in the ice age. Although inundated with water for only a short period of time each Spring, they play a vital role in aquatic and wildlife habitat. Swamps Swamps are shrubby or forested wetlands, located in poorly drained areas on the edges of lakes and streams. Forest swamps primarily exist in river floodplains connected to major river systems. In particular, bottomland hardwood forests filter and purify the waters adjacent to rivers in the Southeast region of the U.S. Vernal pools Vernal pools are small, isolated wetlands that retain water on a seasonal basis.
Vernal pools are also home to many endangered and rare plant species.
Coastal ecosystems are dynamic, diverse areas of enormous ecological significance. They contain some of the nation's most productive wildlife habitats, support valuable fisheries, and provide recreation for millions of people. With proper stewardship, these areas should continue to meet many differing human demands without compromising ecological integrity or biological diversity. The collision of migrating birds with human-built structures and windows is a worldwide problem that results in the mortality of millions of birds each year in North America alone. Over the past 200 years, human activities have directly caused the destruction of valuable wetlands.