Did you know that the world's most biologically diverse ecosystems also happen to be some of the most fragile and endangered?
Wetlands are defined by the U.S. government as "areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetations typically adapted for life in saturated soils."
This usually means marshes, swamps, bogs or fens, but others define the term more broadly to include underground aquifers, wet grasslands as well as mangroves and other coastal areas.
These are all highly efficient environments that play important roles, including maintaining water quality, controlling flooding and erosion, and providing a home to at least 35 percent of all threatened and endangered species on the planet.
One of the most iconic wetlands in the United States is Everglades National Park in southern Florida. This vast subtropical wilderness of cypress swamps, mangrove forests, pineland and hardwood hammocks is home to many endangered species, including West Indian manatees, American crocodiles and Florida panthers.
Although it is the third largest national park in the contiguous U.S., only 20 percent of the original 100-mile-long Everglades watershed is included within the 1.5 million acres that currently make up the national park. Some portions remain intact under other federal and state wilderness designations, but about 50 percent of the original Everglades wetlands has been irrevocably destroyed by rapid agricultural and urban development that began in the 19th century.
This example of environmental degradation is not unique. Wetlands throughout America and the world have suffered greatly at the hands of humans. According to the National Park Service, "less than half of the wetland acreage that existed in the lower 48 states at the time of European settlement remains today."
In response to this ecological degradation, hundreds of million of acres of wetlands across the country are now being managed through various wilderness designations, including national parks, national wildlife refuges and national seashores, among others.
Because there are hundreds of these wetland havens across the country (thousands if you count private- and state-protected areas), it'd be a real challenge to highlight them all, but continue below for a small selection of the most outstanding nationally protected wetlands in the U.S.
Merced National Wildlife Refuge
From Yosemite to Big Sur, the state of California is positively brimming with outstanding scenic vistas. However, one outstanding haven for scenic nature that's not so well-known is Merced National Wildlife Refuge, a birder's paradise located two hours south of Sacramento.
As MNN's Jaymi Heimbuch explains, "A postage stamp-sized place compared to many of the state's other parks and preserves, this refuge is a resting ground for an abundance and diversity of migrating birds — a sight that leaves every visitor in awe."
Okefenokee National Wildlife Refuge
Straddling the border of Georgia and Florida is the Okefenokee, the largest blackwater swamp in America and one of the world's largest remaining intact freshwater ecosystems.
Much of the swamp is populated with bald cypress, swamp tupelo and other wetland flora, and the drier upland areas are filled with massive evergreen oaks and towering forests of longleaf pine. While these upland areas are home to wild turkeys, bobcats, white-tailed deer and Florida black bears, the rich swampland fosters important wetland habitats and breeding grounds for wading birds, alligators, turtles, lizards and many species of amphibians.
According to the U.S. Fish and Wildlife Service (FWS), the swamp was once inhabited by the Creek Indians, who coined the term "Okefenokee," which originates from a phrase that means "land that trembles when you walk on it."
Great Dismal Swamp National Wildlife Refuge
Judging by its name, the Great Dismal Swamp that straddles North Carolina and Virginia might seem like a total drag to visit, but considering the opportunities for birdwatching, hiking, canoeing, fishing and boating, that couldn't be further from the truth.
According to journalist Bill Bartel of The Virginian-Pilot, "More than 280 years ago, what is now the Great Dismal Swamp National Wildlife Refuge was part of a much larger, waterlogged natural area known in land records as the Great Dismal. Called 'great,' possibly because of its size, it was called 'dismal' because that was a common term at the time for a swamp or morass."
Although FWS currently manages about 112,000 acres of the Great Dismal, it's estimated that the original size of the vast swamp land prior to human encroachment was around 1 million acres.
Death Valley National Park
You might not think the hottest and driest place in North America could include a natural wetland, but think again. Saratoga Springs is a desert oasis situated along the southern tip of Death Valley National Park. This marshy, spring-fed wetland is an important home to multiple endemic marine species, including the Saratoga Springs pupfish.
Cumberland Island National Seashore
The crown jewel of Cumberland Island is its 17-mile-long stretch of undeveloped beach, but this remarkable slice of Southern paradise is also home to an extensive 16,850-acre wetland system that includes salt marshes, tidal creeks and mudflats.
In addition to typical wetland wildlife, it's not uncommon to spot Cumberland's iconic feral horses grazing and wading through the island's marshland and mudflats. Although it's quite magical to observe these charismatic equines from afar, the animals' invasive grazing and trampling of these fragile ecosystems has become a serious point of contention among conservationists and the larger public.
Kenai National Wildlife Refuge
While the eastern coast of the U.S. tends to get all the glory for its vast yet fragmented concentration of marshes and swamps, did you know that 63 percent of all U.S. wetlands are in Alaska?
According to the Alaska Department of Environmental Conservation, wetlands cover about one-third of the state of Alaska (about 130 million acres). The vast majority of Alaska's wetlands exist in peace under state and national protections, like Canoe Lake in Kenai National Wildlife Refuge.
Biscayne National Park
We'd be remiss not to mention the importance of another less famous Florida entry: Biscayne National Park. Located off the southern coast of Miami, this 172,971-acre national park protects the coastal wetlands and open waters of Biscayne Bay as well as its adjacent coral limestone barrier islands, including Elliott Key (the first of the Florida Keys).
Perhaps the most astounding wetland environment found in Biscayne is its extensive shoreline mangrove forest. Mangroves, like those seen above, are characterized by their complex root system, which are capable of surviving immersion in saltwater as well as anoxic (low-oxygen), waterlogged mud. Mangrove swamps are unique ecosystems that provide shelter to several threatened wildlife species, from the mangrove cuckoo to the American crocodile.
Klamath Marsh National Wildlife Refuge
This 40,000-acre refuge in southern Oregon was established in 1958 to protect the vital nesting, feeding and staging habitats of migratory birds, including sandhill cranes, yellow rails and various species of waterfowl. The wetland is comprised of wet grassy meadows and stretches of open water, and is the historic home of the Klamath tribes, who lived along its banks underneath piney canopies.
Congaree National Park
Just a few centuries ago, the vast majority of South Carolina was covered in old-growth bottomland hardwood forest. Sadly, after rampant agricultural and logging development wreaked havoc on the land, only a tiny fraction of this special floodplain forest remains in the nearly 27,000-acre Congaree National Park.
Merritt Island National Wildlife Refuge
Situated "next door" to the Kennedy Space Center, the 140,000-acre Merritt Island National Wildlife Refuge is filled with salt marshes, estuaries, sand dunes and hardwood hammocks.
This diverse landscape is home to a plethora of wildlife, including sea turtles, alligators, bobcats, Florida panthers as well as many birds. On any given day, you'll see roseate spoonbills, ibises, ospreys, anhinga, herons, egrets and various species of waterfowl, rails and shorebirds. In addition to its status as a top-notch birding destination, the refuge is also one of several places that you can observe West Indian manatees in the wild.