Wetlands are very important. The native species of plants help prevent floods and filter out pollutants. They also are nurserys for birds and fish. Pictured is a wetland with an invasive species: purple loosestrife. This plant does not belong in Great Lakes wetlands because it takes over and native species are crowded out. Read more about invasive species in the Great Lakes in my book: The Dynamic Great Lakes. The book is widely available at bn.com, Amazon.com and many other fine bookstores.