Swampy South Louisiana, unbeknownst to most people, contains a staggering 25% of America's total wetlands, 40% of its salt marsh. In fact, jumbled and meandering wetlands in South Louisiana are the size of the much better known Everglades[.]
Follow the link for an explanation of the basic ecology concept that wetlands (a.k.a. swamps) are often a good thing for the environment.
The Everglades, by the way, are also endangered by rising sea levels created by global warming. Most of the Everglades are at very close to sea level, so even modest increases in sea level can return much of it to the sea.
Taken together, about half of America's critical wetlands are at risk in these two areas alone.