It can be hell finding one’s way across an extensive boggy moor—the partially dry, rough ground and the absence of any landmarks let the eye rove helplessly into the monotype distance. Everything undulates, the rise and fall share the same muted palette, and the senses dull. But a swamp is different: in it, in addition to water, there are trees and shrubs, just as reeds and rushes are the hallmarks of a marsh. Although water and squelch are everywhere in a swamp, there are landmarks—downed trees or jagged stumps, a tenanted heron nest, occasional islands of high-ground hardwood stands, called “hammocks” in the South. Yet the swamp traveller goes not in a straight line but slouches from quaking island to thick tussock to slippery, half-submerged log. Even with G.P.S. technology, big swamps are places to get lost, and in the past many people with a reason to melt out of sight—Native Americans threatened out of their territory, runaway slaves, Civil War army deserters, moonshiners, and bloody-handed murderers—have hidden in them. For a few seconds, I once considered hiding in a swamp myself.

When I was ten years old, my family lived in a rented house in Rhode Island. Saturdays were free time, and I sometimes went to a nearby swamp. A fishermen’s path circled the swamp. Far out in the water stood the unreachable hulk of a dead tree—branchless, tall, white, and with a large hole near the top. I had somewhere read that great blue herons nested in such snags, and that in one swamp a man had brought a ladder, placed it against a tree, and climbed up to look into a heron nest. The heron stabbed him in the eye as he came level with the nest, and the man, his eye and brain pierced, fell dead from the ladder. I wanted to see if there was a heron nest in this local swamp’s dead tree—perhaps even a live heron, perhaps even the remains of a ladder, perhaps even a sun-bleached skull nearby. When I got to the swamp, I saw a small raft and a pole lying on the bank. There was no one around. I pushed the raft out into the tawny water, got on board, and began poling toward the snag. I was halfway there when I heard furious shouts and screams. Looking back, I saw the two worst boys at my school jumping up and down on the bank and hurling futile clods of mud. I had stolen their raft. After a quick look for a hiding place, I changed direction and took an oblique route to the farthest shore, where I pole-vaulted onto firm land, found the path, and rushed away from the scene of the crime. It was some time before I noticed that I was still carrying the raft pole, and I leaned it helpfully against a tree before continuing home.

Many modern Americans do not like swamps, herons or no herons, and experience discomfort, irritation, bewilderment, and frustration when coaxed or forced into one, except for a few, like my mother, for whom entering a swamp was like plunging into a complex world of rare novelties. My mother’s hero was Henry David Thoreau, the enigmatic New England surveyor-naturalist-essayist. Thoreau has been called the patron saint of swamps, because in them he found the deepest kind of beauty and interest. He wrote of his fondness for swamps throughout his life, most feelingly in his essay “Walking”: “Yes, though you may think me perverse, if it were proposed to me to dwell in the neighborhood of the most beautiful garden that ever human art contrived, or else of a Dismal Swamp, I should certainly decide for the swamp.” He went so far as to describe his dream house as one with windows fronting on a swamp where he could see “the high blueberry, panicled andromeda, lambkill, azalea, and rhodora—all standing in the quaking sphagnum.”

Many people vaguely understand that wetlands cleanse the earth. In fact, they are carbon sinks that absorb CO₂, and they are unparalleled in filtering out human waste, material from rotten carcasses, chemicals, and other pollutants. They recharge underground aquifers and sustain regional water resources, buffering the excesses of drought and flood. In aggregate, the watery parts of the earth stabilize its climate.

Wooded swamps are at the end stage of a fen-bog-swamp succession, legacies of the Ice Age, when the melt started the sequence by first creating stupendously huge lakes. Lake Agassiz covered more than a hundred thousand square miles of Saskatchewan, Manitoba, Ontario, North Dakota, and Minnesota. Lake Missoula covered about three thousand square miles of what is now Montana; its repeatedly bursting ice dams and cataclysmic floods spread through Idaho and Washington and created bizarre giant ripples as the long-ago gushers scoured out the channelled scablands of eastern Washington. The melt turned much of the North American continent into wet ground, with long chains of swamps gouged by no-brakes glaciers that plowed across the terrain. Burly new watercourses captured smaller streams and made deltas and estuaries.

In the nineteenth century, the United States enlarged in a fever of land acquisition: the 1803 Louisiana Purchase, involving eight hundred thousand square miles from the Gulf of Mexico to Canada, doubled the size of the country; in 1819, the Adams-Onís Treaty added Florida and part of Oregon; five hundred and twenty-five thousand square miles of Texas were annexed in 1845; the Oregon Treaty, in 1846, enrolled the Pacific Northwest from Northern California to the Strait of Juan de Fuca. Great oceans and lakes framed the country, and the interior roiled with tangles of rivers like unspooling silver ribbons. All that territory had once held a wealth of wetness—scientists have estimated that approximately two hundred and twenty-one million sopping acres existed in the early seventeenth century, much of it swamps—and two hundred years later many swamplands remained. As the United States pushed its borders, its population leaped from 7.2 million people in 1810 to 12.8 million by 1830, almost doubling in twenty years. The welcoming arms of open immigration became the hallmark of America, and that reputation lingers in global memory, despite today’s more painfully stringent reality.

The original occupants of the continent knew the rivers and swamps, the bogs and lakes, as they knew the terrain and one another. But for most English settlers and European newcomers nature consisted of passive and inanimate substances and situations waiting to be used to human advantage. Preservation and care of nature were not what they had come for.

The first generations of overseas settlers concentrated on claiming the easiest farmland near the shore and in the river valleys. To their mind, there were no local resources. Everything had to be imported or reinvented. As invaders, they had constant battle with Indigenous people who defied them. It was not until the Revolutionary War ended and the Indian Wars devolved into treaty-making that the population noticeably increased and a need for more farmland brought settlers into the upland forests. The growing scarcity of good farmland revived old stories of swamp and marsh drainage. Farmers already knew that a wagonload of “muck” from a nearby swamp would enrich the soil, renewing yields that had weakened over the years. In addition, during the Civil War, moving heavy guns and personnel through swamps was incredibly difficult; soldiers often resorted to laboriously clearing bypass routes. One of the men wrote of wading through knee-deep and deeper mud in North Carolina after the battle of First Gum Swamp: “The brambles [were] thick and thorny, the water coffee-colored, alive with creeping things, the air heavy with moisture and foul odors.” These memories persisted. Across the country, the ongoing stories of vile adventures in the muck made it clear to military, government, and citizenry that something had to be done about the swamps so universally detested. Everywhere there were horrendous mixtures of fen, bog, swamp, river, pond, lake, and human frustration. This was a country of rich, absorbent wetlands that increasingly no one wanted.

After a rainstorm, any curious child who drags a stick obliquely away from a rivulet sees the rivulet forsake its original channel and follow the stick’s trail; the stick dragger has discovered the principle of drainage. It is this innate existential curiosity that has led humans to commit unthinking malfeasances against the natural world. Farmers grew up with shovel in hand ready to cut drainage ditches. The government was solidly on the side of drainage to increase land area, in part for incoming immigrants. In 1849, Congress passed the first of several swampland laws that turned federal wetlands over to the individual states with the right to dispense those water-sodden acreages for purposes of drainage. These laws perpetuated the myth of endless land free for the taking, and showed an inability or an unwillingness to observe changes in nature over the seasons and years.

By the nineteen-eighties, roughly half of America’s wetlands had been wiped out. Aerial photography made wetland size estimates possible, and in 1990 the U.S. Fish and Wildlife Service published a study showing that since the sixteen-hundreds the country’s treasury of wetlands had shrivelled to a hundred and three million acres, and that some states had lost almost all their original wetlands.

The single-minded desire for more agricultural land linked to automation and the transfer of field labor from human to machine, along with the growing customer base of non-farming populations for cheap foods and grains, has come with a terrible cost. Between 2004 and 2009, another sixty-two thousand three hundred acres of wetlands disappeared to agricultural interests and housing developers. And more continue to disappear because of sediment-deposition patterns; fertilizer runoff; spilled and leaking chemicals; increasing floods, storms, droughts, and fires; and today’s rising sea level.

Rising sea level is both subtle and blatant: we hardly notice it until a storm brings vast flooding. For example, at Naval Station Norfolk, in the Hampton Roads region—a natural roadstead channel of deep water in Chesapeake Bay, fed by the James, Nansemond, and Elizabeth Rivers—seawater is now swelling up at an unprecedented rate. The environmental writer Jeff Goodell visited the station and wrote, “There is no high ground on the base, nowhere to retreat to. It feels like a swamp that has been dredged and paved over—and that’s pretty much what it is.”

It is in and around wetlands that the greatest blossoming of biodiversity has occurred—it is not too much to say that we owe our existence to this planet’s wetlands, including fens, bogs, and swamps. Our wholesale destruction of wetlands for the sake of a few decades of growing wheat, rice, soy, and palm oil has been breathtakingly short-sighted. Once again, we are shocked into recognition that most of us live only for the moment.

The great Southern coastal swamps of the United States were and are treasures of the natural world. Some have been exploited and damaged beyond recognition; some are still rich and wonderful, preserved as wildlife refugia or parks. Visitors can share the amazement and delight of the botanist William Bartram, whose exploratory travels in Georgia and Florida between 1765 and 1776 yielded writings and drawings that show a wild, tropical South—warily sensitive Seminoles, violent and crafty alligators, exquisite unnamed flowers, masses of bayonet-like grasses, colossal black oaks. Every fly-fisher will appreciate his description of the mayfly hatch:

Innumerable millions of winged beings, voluntarily verging on to destruction, to the brink of the grave, where they behold bands of their enemies with wide open jaws, ready to receive them. But . . . gay and tranquil each meets his beloved mate in the still air, inimitably bedecked in their new nuptial robes. What eye can trace them, in their varied wanton amorous chaces, bounding and fluttering on the odiferous air!

Bartram was the son of the Philadelphia Quaker John Bartram, who had been appointed Botanist for the American Colonies by George III. John Bartram made the country’s first botanical garden on his Philadelphia property. Father and son often went on botanical expeditions together. One such was to Georgia’s lower Altamaha, where in 1765 they first discovered the Franklinia, in a sandhill bog. This small, beautiful tree is now extinct in the wild but continues to delight American gardeners, who grow specimens all descended from those few seeds collected by William Bartram on his Georgia travels. Thinking of the Bartrams, I once planted the closely related Stewartia in my garden, while I was living in Port Townsend, Washington; it grew handsomely but did not flower during my time there.

A valuable medicinal plant was the Bartrams’ second find. “It grows twelve or fifteen feet high,” William Bartram wrote, “with large panicles of pale blue tubular flowers, specked on the inside with crimson.” This was Pinckneya pubens, the Georgia “fever tree,” a natural source of quinine used by Native Americans to treat tick fever, muscle cramps, parasites, and malaria.

At times, the travels were dangerous or pestiferous, as when Bartram fell asleep next to his campfire to enjoy “but a few moments, when I was awakened and greatly surprised, by the terrifying screams of Owls in the deep swamps around me . . . which increased and spread every way for miles around, in dreadful peals vibrating through the dark extensive forests.” This past spring, in New Hampshire, I heard amorous owls similarly whooping and caterwauling in the woods. One of Bartram’s more admirably descriptive passages pinpoints the belligerence of the “subtle greedy alligator”:

Behold him rushing forth from the flags and reeds. His enormous body swells. His plaited tail brandished high, floats upon the lake. The waters like a cataract descend from his opening jaws. Clouds of smoke issue from his dilated nostrils. The earth trembles with his thunder. When immediately from the opposite coast of the lagoon, emerges from the deep his rival champion. They suddenly dart upon each other. The boiling surface of the lake marks their rapid course, and a terrific conflict commences. They now sink to the bottom folded together in horrid wreaths. The water becomes thick and discolored. Again they rise. . . . Again they sink.

The American biologist and ornithologist Brooke Meanley, who died in 2007, knew intimately every swamp corner that the Bartrams had visited two centuries earlier. He spent most of his professional life in the Southern swamps. Born in Maryland in 1915, and educated at the University of Maryland, Meanley worked as an ornithologist for the Department of the Interior. In his work, he took thousands of pictures of swamp habitats and birds—including many that no longer exist.

During the Second World War, he served for four years, and was stationed in Georgia, rehabilitating returning soldiers with damaged bodies and psyches. His way was to take the jittery men on hikes and bird walks through nearby forests and swamps. One can only guess how many bird-watchers and amateur naturalists found mental balance and lifelong interests in the natural world through these expeditions. Certainly they learned from him that cutting old-growth forests removed vital bird habitat.

Meanley’s years in and around the Southern water lands are encapsulated in his book “Swamps, River Bottoms and Canebrakes.” I had never heard of the Slovac Thicket until I read Meanley’s description: “For its size, the fourteen-acre Slovac Thicket, located in the heart of the Grand Prairie near Stuttgart, Arkansas, packed the most wildlife excitement per acre that I have ever known.” It’s a good bet that a sky totally black with twenty million birds, such as he saw and photographed that day, cannot now be seen.

Swamps and birds go together; when the swamp disappears, so do the birds. The New World warblers (a.k.a. wood warblers), a group of about fifty small passerine birds that migrate from South and Central America to the boreal forests of Alaska and Canada, were Meanley’s favorites. Many are brightly colored, and their complicated high-pitched songs are difficult to hear. They flicker and flit through branches and reeds like sunlight on a windy day and are a challenge to see. In a perfect world, a warbler can live for a decade, but in the world of predatory house cats, wind turbines, and enormous glass buildings a warbler is lucky to live two years. Meanley found that the bottomlands of the I’On Swamp, in South Carolina, were a choice habitat for the Bachman’s warbler, once the seventh most common migratory bird, annually flying up from Cuba to breed in the blackberry swamps and cane thickets of the Southeast United States. The swamp, named for a landowner, Jacob I’On, was the hunting ground for an early American ornithologist, the Reverend John Bachman, who in 1833 first found the songbird. His friend John James Audubon listed the warbler in his “Ornithological Biography.” As other wetlands were drained and cut, warblers found a refuge in the I’On. Meanley counted himself fortunate to have twice seen a Bachman’s warbler in his lifetime—in 1958 and 1963. In his day, he knew that the species was near extinction. It has not been seen since 1988 and is now presumed to have joined the passenger pigeon and the ivorybill.

For Meanley, the prince of Southern swamps was the Okefenokee, which contained up to twenty-five feet of peat deposits, and was once a haunt of the ivorybill. In describing the swamp’s charms, he wrote that it had everything: “The live oak hammocks, alligators and large wading birds, and the legends. In my judgement it is the most picturesque swamp in North America.” It was, he observed, a mosaic of lakes, shrub bogs, and cypress heads and bays, and though much of its cypress had been cut in the early twentieth century, fifty years later, when he was back in the Okefenokee, lusty regrowth allowed him to say that the swamp “looks today as it did when it was the stronghold of the Seminoles and Creeks.”

When I was in my twenties, my then husband and I sometimes vacationed in the Georgia islands—St. Simons or Sea Island—and we went once to the Okefenokee for a motorboat outing. For hours, we prowled the dark water at low speed, bathed in the damp, heady Southern air that always made me happy when I stepped off the plane into its distinctive perfume. I could not count all the wading birds that stalked in the shallows like tall, aloof models. We glided past cypress and their peculiar pointy knees. Our guide said the knees breathed for the cypress. He pulled up to a small island and waved his hand with a grandiose gesture at the mossy ground. I stepped out of the boat and felt the ground move in an undulating roll. It was a mat of sphagnum moss, and although some people say it is like walking on a waterbed, its billowy heave seemed to me more like a wave of dizziness before you pass out—a very slow falling sensation although you remain upright.

My most intimate swamp experience came one summer when I lived in a remote and ramshackle house in Vermont with a beaver-populated swamp half a mile down in the bottomland. I went to the swamp almost every day by a circuitous route through the woods, passing a patch of pitcher plants and two or three sundews, across a brook, following the beavers’ tree-drag ruts to an old stick dam. There were trout in this swamp and beautiful painted turtles. I watched the amazing acrobatics of dragonflies with disbelief that they were actually doing what I saw them do. Even when I sat on the back porch high above the swamp I thought I could catch the green smell of bruised lily pads.

Once, after weeks away, I came back to the house in the late afternoon. I had started reading Norman Maclean’s story “A River Runs Through It” on the plane ride home and decided to read to the end before I went inside the house. It was an utterly quiet, windless day, the light softening to peach nectar. I read the last page and its famous final line, “I am haunted by waters.” I closed the book and looked toward the swamp. Sitting on a stone wall fifteen feet away was a large bobcat who had been watching me read. When our eyes met, the cat slipped into the tall grass like a ribbon of water, and I watched the grass quiver as it headed down to the woods, to the stream, to the swamp.

After the Lewis and Clark expedition of 1804-06 and the Erie Canal’s gradual opening from 1825 onward, the country’s swelling population pushed into the new Western territories. The Great Black Swamp, a product of the excess of mire left over from the glacial melting of the Ice Age-era Lake Erie, and which covered much of Ohio and parts of Michigan and Indiana, inspired visceral revulsion. The Black Swamp froze itself blue in winter and simmered under the summer sun. It was forty miles wide and a hundred and twenty miles long, an elm-ash watery woodland well stocked with snakes, wildcats, moose, birds, malaria-carrying mosquitoes, and unnamed demons, immovably in the way of all who were trying to go west. Travellers forced to splash through swamps under attack from blackflies, no-see-ums, and deerflies, or to make long, tiresome detours around watery areas, complained vociferously and called to the heavens for drainage.

By the eighteen-fifties, farmers noticed that raised stream banks in parts of the swamp were made of dry black soil. They picked up handfuls of it, rubbed it between their fingers, felt the friability and tensile strength, judged its tilth. Then they cut down the stream-bank trees, plowed and planted, and harvested tremendous crops. They said what every farmer in newly opened peatland has ever said as they gathered the first harvests: “This is some of the most productive soil on earth.” Other farmers noticed, and since stream-bank acres were limited, a few men with experience in wet soils tried drainage with ditches and tiles. Excited by their success, the farmers attacked the Black Swamp; a mad make-your-own-land rush was on. In the eighteen-eighties, an Ohio man, James B. Hill, frustrated by the slow work of laying drainage tiles, invented a machine he called the Buckeye Traction Digger. Every farmer wanted one, and the Black Swamp began to dry out.

Pro-drainage legislation helped the process along, and woe betide the landowner who resisted his neighbor’s drain work. In 1915, Ben Palmer of Minnesota wrote a legal guide to drainage. Chapter 4—“Drainage Legislation and Adjudication”—explains, “Thirty-six states of the Union have now enacted general drainage laws for the purpose of providing the legal machinery which is necessary if drainage work involving any considerable amount of land is to be successfully carried on.”

By the early twentieth century, only a pinch of the original Black Swamp still existed—the rest was “some of the most productive soil on earth.” It was taken as a stroke of luck that drainage tiles could be made from the clay deposits beneath the good peaty soil—in a way, the Black Swamp paid for its own annihilation. But a few generations later the productive soils were depleted; the nutrients in organic soils will disappear when they are not replenished. Manure grew scarce as tractors replaced horses. The farm world welcomed synthetic fertilizer. Time passed, and the Maumee River, which drains the Ohio cropland watershed, became a major source of pollution in Lake Erie. I was once on a train that stopped for hours on a bridge over the Maumee River to let freight traffic through. There was no sign—frothy scum, iridescent gloss, or bright algae—to show that just below the train flowed Lake Erie’s poison enemy.

Aside from the joys of draining, there was another pot of gold at the end of the swamp: fortunes for the nineteenth-century woodland owners and professional timbermen who cut down the wetland forests not only of Ohio but of Michigan, Indiana, Illinois, Georgia, Louisiana, Florida, and any other state north or south that had swamp forests—taking irreplaceable giant elm, ash, oak, birch, poplar, maple, basswood, hickory, and chestnut.

Ohio residents, by and large, did not appear to miss their state’s swampland. Sharon Levy, a science writer who specializes in water and wetland issues today, wrote of the mark the Black Swamp made on Ohioans:

The tough people who conquered the Great Black Swamp did so at great personal expense, and they’ve passed down a deep and abiding loathing of wetlands. They are considered a menace, a threat, a thing to be overcome. These attitudes are enshrined in state law, which makes impossible any action, including wetland restoration, that slows the flow of runoff through those miles of constructed drainage ditches—the very conduits that, after each heavy rainfall, deliver thousands of metric tons of phosphorus and nitrogen to the Maumee, and onward into Lake Erie from which millions of people drink.

One authority on water, William Mitsch, has suggested that if ten per cent of the old Black Swamp soils were allowed to become wetlands again they would cleanse the runoff, yet Ohioans remain powerfully anti-wetland. Even private efforts to restore small wetland areas are met with neighbors’ complaints about noisy frogs and fears of flooding. Still, despite all odds, there exists the Black Swamp Conservancy, a land trust that oversees twenty-one thousand acres of wetlands. Hundreds of active Black Swamp Conservancy members are doing their best to restore and protect remnants of this great swamp. Can they persevere?

My mother’s favorite book when she was a teen-ager, in the nineteen-twenties, was one that she loved for its swamp setting, Gene Stratton Porter’s “A Girl of the Limberlost.” The Limberlost Swamp is in northeast Indiana, forty miles west of the Great Black Swamp. Porter’s home was near the Limberlost, which, though small at thirteen thousand acres, was still a diverse and complex system of streams and ponds eventually draining into the Wabash River. The Limberlost was made up of timber, reeds, sphagnum moss, orchids, sundew, pitcher plants, and grasses that nurtured great crowds of waterbirds and migratory birds, snakes, frogs and other amphibians, deer, muskrat and beaver, mink, and an encyclopedia of insects, including rare moths and butterflies.

There are at least two and probably more stories of how the name Limberlost originated. In one, a man named James Miller, so physically agile he was called Limber Jim, was hunting in the swamp. He became hopelessly lost, walking in deadly circles before he began to blaze trees in a straight line. His friends found him and referred to the swamp ever after as the place where Limber was lost. Another story refers to Limber Jim Corbus (what is it with these flexible Indiana men?), who also set out for a day’s hunt in the swamp and became lost, but blazed no trees and was never found.

Despite being considered a “nature” novel, “Girl of the Limberlost” is the usual American story of taking from nature for personal gain. The book champions its heroine, Elnora, who collects the chrysalides of moths, then raises, kills, and mounts them. After her miserable first day in high school, where she is scorned as an out-of-fashion backwoods hick, she sees a placard in the local bank window offering cash for moths, cocoons, and pupa cases. Elnora needs money to buy the kind of nice clothes and cosmetics that will let her join modish high-school cliques and pay for her books. She describes her moths to the placard’s writer, who tells her, “Young woman, that’s the rarest moth in America. If you have a hundred of them they are worth a hundred dollars according to my list.” Elnora is on her way to wealth, a career, a rich husband, and all the rest of it, thanks to the corpses of the Yellow Emperor moth.

Against Porter’s protests, the Limberlost was ruinously drained for farmland by steam-powered dredges between 1888 and 1910. But in the nineteen-nineties Indiana readers who treasured Porter’s book bought some of the original swamp acreage and, with help from several conservation groups, started restoring the swamp by removing drainage tiles. As the water deepened, they planted native sedges, grasses, trees, and water plants. Today, a small piece of the Limberlost exists again, serving as a tourist attraction and a home to muskrats, ducks, herons, turtles, fish, and insects. The Yellow Emperor moths are still around.

It is an important decision to restore even a small piece of wetland that has been severely mauled—once land is apportioned to owners, there can be no easy path to restoration of a natural habitat. Bogs and swamps take thousands of years to build up and develop; humans and their machinery can wipe out those centuries in a few months. But once a few interested people put on their boots and go into the damaged wetland, and once their curiosity is aroused about how the water moves, and what plants, amphibians, and birds formerly thrived in their local remnant swamp, they are hard to stop. There is unequalled joy in restoration.

Mangroves are marine trees. They grow in brackish and saline water along Southern and tropical shores—their splayed-out roots resemble the “cages” that supported Victorian hoop skirts—and they form peat. Their specialized home ground, such as Florida’s Everglades, is smelly and muddy. There are roughly sixty species of mangrove, mostly found in Asia, and the strongest forests are those of mixed species. Mangrove swamps have been called the earth’s most important ecosystem, because they form a bristling wall that stabilizes the land’s edge and protects shorelines from hurricanes and erosion, and because they are breeding grounds and protective nurseries for thousands of species, including barracuda, tarpon, snook, crabs, shrimp, and shellfish. They take the full brunt of most storms and hurricanes, and generally survive—but not always. Hurricane Irma, in 2017, hit the mangroves of Big Pine Key, in Florida. While shrubs came back after a time, the mangroves did not. Some saw the cause of mangrove death as trapped standing salt water, but others thought that the storm surge had plastered a very fine coating of sediment on the vital aerial roots, which dried into a choking hard sealant.

Mangrove leaves fall into the water and, as they decay, become the base for a complex food web benefitting algae, invertebrates, and the creatures who feed on them, such as jellyfish, anemones, various worms and sponges, and birds. The peat that mangroves form is especially soft and deep, ideal for clams and snails, crabs and shrimp. The mangrove’s roots filter out harmful nitrate and phosphate pollutants. The tangled branches above the water make a safe habitat for literally thousands of species of insects that attract birds. They offer resting places for migrating birds and nesting places for others, including kingfishers, herons, and egrets. Monitor lizards, macaque monkeys, and fishing cats on the hunt prowl the branches. Below the water, the knots of interlaced roots protect tiny fish from the ravenous jaws of larger fish, and even manatees and dolphins take refuge in these swamps. Mangroves interact with coral by trapping muddy sediment that would smother the reef, while the offshore reef protects the mangroves and seagrass beds from pummelling waves. Structurally, mangroves form an enormous hedge that extends down into the water and high above it. They are a major part of the “blue carbon” group that absorbs CO2, which also includes the salt marshes, seagrasses, and beds of kelp and other seaweeds.

With all these virtues, it would seem that mangroves must be the most valued trees on earth. Unfortunately, that is not the case. Although climate researchers see mangrove swamps as crucially important frontline defenses against rising seawater and as superior absorbers of CO2—they are five times more efficient than tropical forests—they are in big trouble, and mangrove removal is a constant threat.

In 2010, a count showed that about fifty-three thousand square miles of mangrove forest protected the earth’s coasts. But six years later thirteen hundred square miles of mangroves had been lost to palm-oil and rice farms and shrimp aquaculture. In some cases, mangrove forests have been removed to make room for shrimp ponds; in other cases, the shrimp ponds are set back from the mangroves, but the released effluents and pollution still damage and degrade the mangrove forest by changing the water’s salinity, altering the mangrove’s ability to take in nutrients. The consequence is slow death for the mangroves.

Many countries have tried to master the complexities of mangrove restoration, with mixed results. Choice of the right site and a mutually beneficial mix of species is critical. Some well-intentioned restorers planted greenhouse-raised single-species saplings in mudflats that mangroves had never grown in, or that were exposed to erosion and strong waves. Yet mudflats have a low oxygen supply because they are constantly wet, and mangroves need to breathe.

A different approach was that of the Florida biologist, ichthyologist, and wetlands ecologist Roy (Robin) Lewis III, who worked out the details of effective mangrove restoration. Repetitive observation can unravel the mysteries of events and processes. Lewis, who was born in 1944, was still a graduate student when he began working in mangrove swamps. “I spent a decade working in the mangroves before I started to have an understanding of what was going on,” he once remarked. He dedicated years to puzzling out the rhythms of mangrove happiness. He observed that, in the natural order, when a mangrove tree died, plentiful seeds from nearby healthy mangroves floated in and rooted themselves. The problem with many restoration attempts was location. Just any random part of a shoreline would not work. The flow of water had to be correct. Mangrove roots need to be sometimes wet and sometimes dry. Lewis worked out a wet-dry ratio of thirty to seventy. “They have a short period of wetness, and then they have a long extended period of dryness, and those alternate daily,” he told a reporter for the Smithsonian Institute. “That’s the secret: you’ve got to replicate that hydrology.”

His first trial of this theory came in 1986, with thirteen hundred acres of damaged and dead mangroves half smothered in dirt and weeds on a flat site near Fort Lauderdale. After several years of experiment and study, Lewis brought in earth-moving equipment to create a gentle slope of land that would allow the natural tidewaters to ebb and flow. Then he waited. The tides brought mangrove seeds that took root, and five years later three local species of mangroves were growing. Fish moved into the sheltering roots, and the birds followed. No mangrove saplings were hand-planted; all the new trees grew from waterborne mangrove seeds. Lewis’s way of working with nature—observation and study, planning and patient waiting—has become the gold standard for restoration.

It is usual to think of the vast wetland losses as a tragedy, with hopeless conviction that the past cannot be retrieved. Tragic, indeed, and part of our climate-change anguish. But as we learn how valuable wetlands are in softening the shocks of the changing climate, and how eagerly the natural world responds to concerned care, perhaps we can shift the weight of wetland destruction from inevitable to “not on my watch.” Can we become Thoreauvian enough to see wetlands as desirable landscapes that protect the earth while refreshing our joy in existence? For conservationists the world over, finding this joy is central to having a life well lived.

It is of course possible to love a swamp. I remember another small and nameless Vermont larch swamp, which could be reached only by passage through a dark and gloomy ravine that I thought of as the Slough of Despond.

At the bottom of the ravine ran Jacobs Chopping Brook. The flurried, emotional water of the brook contrasted with the black glass disk of swamp water that seemed made to reflect passing clouds but under rain showed itself as dimpled pewter. It has been fifty years since I last saw it, but it is still with me.