DARIEN — It meanders 137 miles through the wild heart of Georgia, a blackwater beauty that nourishes longleaf pine forests, cypress swamps, saltwater estuaries and the barrier islands that protect the Atlantic coast and migratory birds alike.

The Altamaha River — “the Amazon of the South” — flows free with few latter-day intrusions like bridges or factories. It’s a biodiverse playground for West Indian manatees, piping plovers, eastern indigo snakes, gopher tortoises, the hairy rattleweed and dozens of at-risk species. It’s a recreational oasis, too, for deer and turkey hunters, fresh and saltwater anglers and, increasingly, kayakers, birders and hikers. Its history fascinates; its culture abounds.

It’s also a river corridor under siege.

A paper mill, municipal wastewater and agricultural runoff pollute the Altamaha. Development, anything from a 10-acre subdivision to a 5,000-acre horse farm, gobbles up precious buffer lands. Rising seas, warmer temperatures and killer droughts harm flora and fauna.

The river, though, benefits from one of the nation’s most ambitious, successful and little-known conservation efforts. Nearly $100 million has been spent the last dozen years buying up huge swaths of land along the Altamaha. A 40-mile-long corridor, from Jesup to Wolf Island National Wildlife Refuge, has been protected — along both sides of the river.

“Looking back 15 years ago to where we are today, you’ve just got to say ‘Wow,’” said Dink NeSmith, a newspaper publisher in Jesup who has placed five miles of Altamaha River frontage in conservation easement. “This is a cornucopia of wildlife. We got deer, wild turkey – unfortunately too many hogs – squirrels, rabbits, duck hunting, dove hunting (and) oxbow lakes and cypress trees. These are natural resource heirlooms that we want to pass on to our children, their children and their children’s children.”

Saving a river corridor, of course, requires much more than nature-loving benefactors, nonprofits and private foundations. The Altamaha received generous support from an alphabet soup’s worth of federal and state agencies. Georgia’s Department of Natural Resources (DNR) and the U.S. Fish and Wildlife Service (Service) top the list. The U.S. Department of Defense (DOD), known more for blowing things up than conserving them, plays a critical financial and environmental role in the Altamaha’s survival.

The river is a stellar example of a “conservation corridor,” a lengthy, protected bulwark against the ravages of over-development and a warming climate. Within 45 years, for example, the Southeast is projected to lose a South Carolina-sized amount of forest. The region’s population could double. The South’s natural, historical and cultural worlds are threatened. Unless something is done.

The Southeast Conservation Adaptation Strategy (SECAS), a coalition of government and nonprofit groups, aims to protect large swaths of land, myriad at-risk species and a distinctly Southern way of life heavy on hunting and fishing. The plan, with a target date of 2060, enlists business, industry and the military — entities not typically synonymous with conservation — in “a connected network of landscapes and seascapes that supports thriving fish and wildlife populations and improved quality of life for people.”

“The Altamaha River fits perfectly into the SECAS mold,” said Cindy Dohner, the Southeast Region director for the Service. “It’s a wild and beautiful river corridor teeming with at-risk, threatened and endangered species as well as recreational opportunities. It’s also a testament to the power of cooperation – between the feds, the state of Georgia, the military and private landowners – to keep working lands working for the betterment of the economy.”

Pelicans and plantations

Wolf Island is fast eroding. Shifting sands and rising seas have lopped hundreds of feet of beach and marsh from its seaward side. The refuge, though, remains quite popular with migrating birds who traverse the Atlantic Flyway. And, as the easternmost reach of the Altamaha River basin, Wolf Island is an ideal spot to begin a recent, 40-mile upriver sojourn.

A handful of piping plovers, a species threatened with extinction, waddle along the beach before heading back north for the summer. Hundreds of red knots fly from ocean to beach to marsh and back again in search of clams, oysters and mussels. Orange-beaked American oystercatchers, lumbering brown pelicans, least and royal terns, black skimmers, godwits and any number of ducks parade and preen along the shore

The Altamaha dumps 100,000 gallons of water into the sound each second, concocting a hearty fresh-salt water cocktail that nurtures everything from tiny food-source plankton to endangered Atlantic and shortnose sturgeons. Clams, sea worms, snails, crabs, black drum, croaker and spotted sea trout all depend on the watery mix. Pickerelweed, a plant favorite of threatened West Indian manatees, grows in the marsh. White shrimp – a commercial fishing stalwart – spawn offshore, migrate upstream into tidal creeks before returning downriver as adults to the estuary and open waters to spawn or get scooped up in nets.

“You need to keep the river clean for the fishing and all the tourists and the yachts and the kayakers coming through,” said Benton Wilson, while gutting flounder and whiting for a wholesaler along the docks of Darien. A nearby shrimp boat readied for a five-night trawl. An American alligator sunned along the banks of the river below the U.S. 17 bridge.

“If you don’t protect it, then you get pollution and the river’s [quality] will go down and all the fish are going to die, the crabs are going to die,” Wilson, 74, continued. “You need to protect it now so you can save it for the future.”

Fishing and tourism are big business in the Altamaha corridor. Duck, turkey, deer and boar hunters roam the state-run wildlife management areas (WMAs) that line the river from below Darien to above Jesup.

The WMAs protect more than 141,000 acres. Add property managed or controlled by the U.S. Marine Corps, the Service and The Nature Conservancy and nearly 200,000 acres are protected. In all, more than 40 miles of property, from Wolf Island to Jesup, will forever remain undeveloped.

In 2011, the Service designated the Altamaha a “critical habitat.” The Nature Conservancy labels it one of “America’s Last Great Places.” The state of Georgia says the river, with more than 120 rare or endangered plants, fish, mussels and animals, is a “high priority” for conservation.

“The Altamaha corridor is spectacular, with such a range of species and habitats: tidal areas with forests; salt marshes; longleaf pine forests; and the wonderful delta,” said Christi Lambert, who has spent 25 years protecting the river for the Nature Conservancy. “I love the river. It’s such a special place. It takes care of us.”

Most of the land bordering the Altamaha was once slash and loblolly pine bought from Rayonier, International Paper and other timber companies and set aside for hunting and fishing.The timber companies work diligently with the state, the Service and others to make sure the deals work in a timely fashion. Increasingly, though, Georgia’s DNR and the Service seek new “customers” keen on different recreational activities. Altama Plantation, for example, a 4,000-acre state-owned tract outside Brunswick, offers hikers, bikers and birders miles of carriage roads and sandy trails wending through an old rice plantation steeped in history.

“How quietly flow thy peaceful floods”

The King of England granted William Hopeton, a wealthy South Carolina grower, the title to Altama in 1763. Rice gave way to Sea Island cotton, which was shipped downriver to Darien for export to England. The Civil War and slavery’s demise killed cotton, but wealthy industrialists, including the DuPonts, bought Altama and added stately homes, a horse track, an airstrip and a swimming pool.

Naturalist William Bartram – “How quietly flow thy peaceful floods, O Alatamaha!” – took a mesmerizing 50-mile canoe trek upriver in 1773 and discovered a tree found nowhere else. (He named it for Benjamin Franklin.) Flat boats filled with cotton and tobacco floated from the headwater Ogeechee and Oconee rivers down to Darien in the early 1800s. Hand-hewn cypress, oak, sweetgum and poplar were fashioned into gigantic rafts and guided downstream to the bustling port town.

Trains and trucks, and the denuded forests, killed river traffic. Timber companies returned the corridor to a natural state, albeit with quick-growing pine trees devoid of the majesty of the swamp cypress and Ogeechee lime.