Fisher still tries to find that freedom. He follows deer trails, crawls through undergrowth, climbs to mountain ledges that even grazing livestock cannot reach. Often, he does so by trespassing; despite new laws that allow people in England to roam freely on some undeveloped private lands, the public still has access to less than 10 percent of the landscape. His greatest challenge, though, is simply that there are not many places in Great Britain that are not unmistakably marked by human hands.
When he can, Fisher travels to North America, where he seeks out landscapes that serve as reminders of what Britain might have been. Once, in Yellowstone National Park, he saw a pack of wolves emerge from a forest’s edge into an open meadow—he fell down on his knees, he says, from the impact of that vision. But it was the wildwood, the simple trees, that broke him. He was hiking in New Hampshire’s White Mountain National Forest when he suddenly stepped out onto a rocky overlook. From there, he had a view across more than three thousand square kilometres of woodland. “I just cried my eyes out,” he says. “I mean, you can’t have those experiences in the U.K., because they don’t exist.”
* The Irish poet Seamus Heaney described the skeleton of an Irish elk that he saw in a museum as “an astounding crate full of air.”
* The horn is thought to have been a 14th-century gift from Germany.
* California’s flag may have another ecological reference. The bear is shown standing on strangely hummocky soil; some biologists believe these lumps represent the billions of pocket gopher mounds encountered by early pioneers. California’s settlers waged war on the gophers as vermin, though they remain abundant in some areas.
* This is made possible by a compact body that powers long, lightweight legs, a physiological design described by one pronghorn expert as “four chopsticks in a bratwurst.”
† Asia also has cheetahs; they once ranged over a huge territory from the Mediterranean coast to India, but now survive only as a critically endangered species in Iran. In Africa, they were formerly numerous and widespread; they’ve lost 76 percent of their historical range on that continent.
* It also happens to be the historical “plant badge” of my own ancestors, the Clan MacKinnon.
Chapter 7.
UNCERTAIN NATURE
In around 1620, a Flemish artist named Frans Snyders completed a painting called Fish Market for the wall of a tax collector’s house in the Netherlands. The canvas is unlikely to make you want to swim in the waters off Antwerp. Dead things of the sea lie heaped upon a table, and there are pincers and tentacles and many, many eyes. To one side stands a fishmonger—a portrait of a man among monsters.
Look awhile longer, and you begin to see that all those terrible creatures are only ordinary animals: cod, herring, halibut, a bottlenose dolphin, lobsters. It’s just that nearly everything is oversized. There probably never was any actual fish stall in the Netherlands with such a madcap sprawl of seafood; at the same time, the image is far from fantastical. Every species but one that Snyders depicted was once fished in the Wadden Sea off the Netherlands coast. The lone exception is a red-footed tortoise, a native of South America that must have made it to Europe on a Dutch trader’s ship.
It was thought at one time that artists had better vision than the rest of us—that through painstaking hours attempting to capture the outrage in a squid’s eye,* a painter like Snyders could develop magnifying vision. Science ultimately showed that it was impossible to improve eyesight through repetitive exercises, though George Perkins Marsh, for one, couldn’t bring himself to believe it. Struggling with bouts of near-blindness as a boy, he was unable to read books and instead studied the landscape around him. How well your eyes worked, he discovered, mattered less than knowing what you were looking at. “Sight is a faculty,” Marsh wrote. “Seeing is an art.”
It is the same with the natural world today. We cannot hope to look at a wild landscape and see its history with our eyes; only the mind’s eye can capture it. The living world has been depleted, but it has also been transformed. This is the reality that Heike Lotze, a marine ecologist at Dalhousie University in Nova Scotia, sees in Snyders’s painting.
Lotze grew up on the Wadden Sea and is one of those people who seems to carry an ocean breeze in her pocket wherever she goes. Her childhood home near Norden, Germany, was just behind a low berm that centuries earlier had been the first dike in the area to claim land from the sea, and is now a roadway with a name that translates roughly as Carrot Street. The high tide has not kissed the Carrot Street dike for a long, long time. By the time Lotze was born, the coast was five kilometres away from her family’s home, and the sea was held back by an eight-metre-high wall.
Thanks to Lotze, the historical ecology of the Wadden Sea is now one of the most exhaustively studied on the planet. The sea is a long, narrow strand of water that separates mainland Netherlands, Germany and Denmark from a chain of barrier islands known as the Frisians. The Wadden is the world’s largest intertidal area, meaning there is no other place on earth where so much water gives way to land, and vice versa, between the tides. At high tide it is a shallow sea, and at low tide mainly a mud flat.
The Wadden formed about 7,500 years ago, at the end of the last ice age, and the first human settlers arrived not long afterward. It was probably a welcoming, if muddy, home. Despite receiving silt from several of Europe’s major rivers, including Germany’s longest, the Rhine, the Wadden Sea is thought to have had clear water, filtered in part by the stillness of its coastal wetlands and in part by a constellation of filter-feeding life forms. It was a strangely soft place—the Wadden has almost no natural rock besides erratic boulders set down here and there by retreating glaciers. The only hard surfaces on the ocean floor were produced by living things: huge beds of beach oysters and blue mussels, along with the strange, soda-straw reefs of Sabellaria spinulosa, a sea worm. Above all else, the Wadden was a true sea: a nearly complete natural system in and of itself.
Historical ecologists have a maxim for what typically happens when human beings move onto a new landscape: we eat the big ones first. The earliest Neolithic hunters and gatherers fed themselves mainly from the land, hunting boar and deer, beaver and otter, and looking to the sea mainly for ducks, seals, porpoises and stranded whales.* By the time of the Roman Empire, nearly every living land animal was on the table. Voles—rodents similar to mice—were an important food, but so was such unusual fare as foxes, wild cats, hawks and crows. Yet it wasn’t until the Middle Ages, about 1,500 years ago, that the people of the Wadden shore, struggling to feed themselves from an increasingly empty landscape, finally focused on fish. Even then, they drew mainly from freshwater lakes and rivers. It took another seven centuries before the stocks of salmon, sturgeon and pike were in decline. Once again, human adaptability provided a way forward, with a hard turn toward the sea.
It was an extraordinary moment—a kind of rebirth. The wild abundance of the land was gone and forgotten. Yet in the sea there was wealth beyond imagining, and that treasury would help fuel the European empires that would go on to reach around the globe. It was a time of such strange sights as sailing ships designed not only to keep sea water out, but also to store it inside the hull, so that fish could be delivered, alive, to distant ports. It was a time when a baker might rise before dawn, light lamps fuelled with the rendered fat of whales and seals, and start cracking eggs taken from seabirds—thirty thousand eggs a year were gathered on the Wadden Sea’s barrier islands for the Amsterdam bakeries alone. The markets were full of wild waterfowl, and the Netherlands’ first cookbook featured a recipe for porpoise pepper steak. The arrival of the harbour porpoise was considered as sure a sign of summer weather as flights of swallows were the heralds of spring.*
The first marine species to disappear from the Wadden Sea were the whales. By the early 1700s, the entire Atlantic Ocean population of grey whales had been wiped out, and the northern right whale could no longer be found anywhere in Europe. A pattern was quickly established: in the beginning, t
otal plenitude, and within a few centuries, near eradication. Whales, dolphins, porpoises, seals, seabirds, haddock, houting, cod, rays, plaice, sole, dab, herring, anchovies, sprat, salmon, flounder, eel, lobster, even peat moss, even seagrass: nearly 90 percent of the Wadden Sea’s major species are now classified as depleted. More than a fifth have been extirpated entirely.
Diking has shrunk the Wadden Sea to half its original size, to the point that the Rhine River is no longer said to flow into it. The delicate blurring of land and water is gone. Until one thousand years ago, settlers on the Wadden lived on mounds raised above the marshes or built temporary villages among shifting dunes. Today, the Wadden is a hardened coast, with more than seven hundred kilometres of human-built stone or concrete shoreline. The oyster and seaworm reefs are gone, and the eelgrass meadows have largely been replaced by an invasive species, cordgrass, that was planted to help stabilize the shore against erosion. The Wadden is so changed that its waters have not been clear in living memory; so changed that the remaining porpoises make their appearance not in summer but in winter; so changed that not one of the species that appears in Snyders’s Fish Market—not a single one—is still commercially fished on the same coast today. So little remains of a natural system that was once nearly self-contained that at least one biologist has suggested the Wadden Sea should no longer be considered a sea at all.
For Lotze, the older Wadden Sea is a place she knows only from history and statistics, like a memory at the tipping point between remembrance and forgetting. Today, much of the Wadden is protected in national parks. With its fishing days all but done, the economic linchpin of the Wadden is tourism: people come to witness what they see as a wild ocean. Even the remaining fishermen, who bring in fish barely longer than their hands, often refuse to believe the history that Lotze tells them. “People think I’m just making things up,” she says. “They are determined that there were never bigger fish in the Wadden Sea.”
Recently, residents have become concerned that something strange is happening in their local waters. Fully protected from hunting, the Wadden’s harbour seal population has rapidly boomed from scarcity to twenty thousand animals or more. In the past, the sea was home to twice that many seals, but to people today, it’s like nothing they’ve ever seen. They describe the return of the seals as “unnatural.”
There are places where the human impact is overwhelming; no one expects that all eighty species of fish that once lived on or around the island of Manhattan, for example, might somehow still be swimming through the sewers of New York. But how deep is the overall scale of change, and how wide?
To begin to get a sense of this, imagine African elephants moving across a savannah dotted with trees. The scene is wondrous, the herd seeming to move more to the rhythm of clouds than to the hurried pace of human beings. The poet John Donne called elephants “the only harmless great thing,” but then, Donne was not a botanist. A clan of two hundred African elephants will eat or otherwise destroy more than sixty tonnes of vegetation per day—an equivalent weight of hay would feed a herd of more than five thousand cattle. Of course, elephants aren’t eating hay. They’re eating almost anything green they can find, and if that means tearing down a fifteen-metre-tall tree to reach its highest leaves, then that is what they will do.
In the late 1800s, elephants were almost totally wiped out by ivory hunters in the Serengeti region of Central Africa. Today, the Serengeti is familiar from nature documentaries and the pages of National Geographic as a great, grassy plain—but that’s not what the region used to look like. In the 1930s, much of it was a dense forest. Colonial administrators set the area aside as parkland in large part because it was sparsely inhabited—Maasai herders had abandoned the region because the bushy landscape harboured the tsetse fly, which can carry potentially lethal sleeping sickness. Then, in 1955, elephants began to return. Almost immediately, the forest started to disappear.
As the elephant population recovered in various locations across Africa, the same pattern repeated itself: woodlands went into retreat, and grasslands began to advance. For years, this was referred to as “the elephant problem” and considered unnatural—the outcome of too many elephants. Today, it is more often looked to as an example of how different a complete ecological system can be from one that is missing key species.
Elephants are known as ecosystem engineers, one of a list of animals—from beavers and sea turtles to earthworms and humans—that radically reshape the landscapes they live on. The large-scale changes these species create trickle down. Forests mauled by elephants are home to larger numbers and more varieties of lizards, for example; the Parker’s dwarf gecko prefers these woodlands so strongly that they abandoned their home trees when scientists experimentally repaired the elephant damage. Most herd animals and antelope also prefer elephant savannahs, which provide few places for predators to hide and where the broken trees sprout new shoots close to the ground. Even elephant droppings are useful, offering moist hideaways for frogs in the dry season and, in one unenviable study of dung piles in Cameroon, spreading the seeds of ninety-one species of plant. Elephants also produce waterholes—I once watched a fully grown female work her way down into the mud of a wallow until only the tip of her trunk stuck out like a snorkel—and in at least one case are even known to make caves. On Mount Elgon in Uganda, elephants have been scraping away at salt deposits for perhaps twelve thousand years, resulting in caverns that reach as much as 120 metres into the hillside and are used as shelter by animals ranging from leopards to bats. They do most of their salt mining in the dead of night.
Remove just this single species, elephants, and you end up with a different environment. Now consider the fact that Africa was once home to ten million elephants, or twenty times as many as live there today. Note that, at the end of the last ice age, elephant-like animals roamed every continent except Antarctica and Australia. There were even dwarf pachyderms on many islands, from the Channel Islands of California to Wrangel Island in Arctic Russia.* Elephants, mammoths, mastodons and the like have disappeared from 90 percent of their Pleistocene range, and they probably affected their habitats in much the same way as modern elephants do in Africa and Asia. One mystery that ecologists struggle with, for example, is why there are grasslands in many parts of the world that have adequate soil and rainfall to support forests. A possible explanation is that elephants and other plant-eating megafauna kept the trees from encroaching and allowed prairie ecosystems to take hold. Even the far north, today a world of wet tundra, was once widely covered with a dry, grassy steppe—which may have depended for its existence on heavy grazing by mammoths. Supposing ancient mega-herbivores shaped only the world’s grasslands (there’s little reason to imagine their influence stopped there), we are already talking about nearly half of the earth’s terrestrial surface.
One other species may have benefited in extraordinary ways from elephant engineering, and that is us. Among the most durable findings in the field of environmental psychology is that people prefer natural settings over the built environment. Among natural landscapes, however, we show the greatest preference for open spaces dotted with trees, with a little water nearby—picture the views from the high-rises that famously border Central Park in Manhattan; as the biologist E. O. Wilson puts it, “to see most clearly the manifestations of human instinct, it is useful to start with the rich.” This predisposition has proven true in experiments across cultures and generations with a consistency that has given rise to the “savannah hypothesis,” which suggests that we value such places because they resemble our ancestral home—the plains of Africa where human beings evolved.
Those plains are also precisely the type of landscape that elephants create. Indeed, we now know that the Maasai herders who had largely abandoned the Serengeti by the time it was declared a protected area had in fact lived there when it had elephants and returned with their cattle as the elephant population recovered. The most pronounced marks that elephants leave behind are their trails, tamped hard
underfoot and perfected over centuries to find the line of least resistance through hills and valleys. Within memory, an elephant route that stretched across much of northern Uganda was considered the best road in that country, and, as with the buffalo trails in North America, some such ancient pathways have gone on to become modern highways or railroads. Archaeologists continue to argue about how it is that early humans spread with such remarkable speed around the globe once they finally left Africa. It’s not hard to imagine that, often enough, we followed in the footsteps of elephants and other animals. The first human beings to arrive in these new worlds thousands of years ago were perhaps similar in at least one way to the European explorers who came in the age of sail: they discovered a world that had already been engineered by its inhabitants, and would forever be changed by the new arrivals.
There is probably no species that doesn’t leave behind a shadow as it burns out of existence. Even small animals can be ecosystem engineers. Indian crested porcupine burrows shape Middle Eastern deserts, for example, and even appear to affect relations between people and lions, tigers and leopards, which if injured in an encounter with a porcupine are more likely to start hunting humans; the infamous Leopard of Gummalapur, which killed forty-two people in India, was found to have two quills stuck in one paw. Honey bees, which are not native to the Americas or Australia, are endlessly promoting plants with flowers that they can pollinate at the expense of less accommodating species. Such ripple effects have come to be known as “cascades,” and some of the most potent involve those flesh-eating animals we call predators.
The Once and Future World Page 10