Inheritors of the Earth Page 6

  So, here we have an Anthropocene conundrum. Borneo’s elephants were almost certainly introduced a couple of hundred years ago, they eat and squash a lot of native vegetation, cause trouble when they emerge from the forest into oil-palm plantations and farmers’ fields and leave huge mounds of dung whenever they walk on the roads. Given these possible ‘negative impacts’, it could be argued that Bornean elephants meet the international definition of an ‘invasive alien species’, which means that they should, in principle, be controlled or removed.29 The counter-argument is that there have probably been elephants of one kind or another in Borneo in the distant past, that the ‘normal’ state of the world’s vegetation is to have very large animals blundering around in it and that Borneo’s proboscideans are genetically unique.30 The sultan’s gift probably originated from an elephant population that no longer exists, most likely from Java. If so, they represent the sole surviving population of Javan elephants. According to Prithiviraj Fernando from the Centre for Conservation and Research in Sri Lanka, they are vital to elephant conservation and must be protected. Elephants also attract tourist income. They simultaneously have both beneficial and negative impacts.

  Elephants were introduced, or reintroduced in the case of Pilanesberg, to the only two places where I have come face to face with so-called ‘wild’ elephants. It seems that it is time to stop yearning for a pristine, wild world. We are living on a fundamentally human-altered planet, and there is no longer any such thing as human-free nature. That stopped millions of years ago in Africa as hominids evolved, over a million years ago in southern Asia once Homo erectus arrived, hundreds of thousands of years ago in Europe and the remainder of Asia, where Neanderthals and Denisovans roamed, ten thousand to fifty thousand years ago on most of the rest of the continents with the spread of our own species, and many hundreds of years to several millennia ago on most of the world’s islands. We cannot reverse time. Instead, we should appreciate changes that are positive as much as we regret any losses. Yes, we have caused the extinction of most of the world’s largest land mammals but the American bison is back within the confines of where we allow them to roam. Elephants are doing well in Danum. The grey whale is again migrating in impressive numbers along the western seaboard of North America. Deer and foxes are in our backyards. Nature is fighting back.

  3

  Never had it so good

  The hares and rabbits are nowhere to be seen, perhaps on account of the buzzard hunched up on the fence post and the lingering scent of the fox that visited in the night. The rabbits rarely venture far from the security of their underground burrows. The fresh droppings of brown hares adorn the summits of old ant mounds, but they hide in the long grass in the daylight, avoiding the preying eyes of the buzzard. The buzzard is more interested in earthworms, or at least accepts that worms are easier to catch. Wagtails and starlings accompany ponies in the meadow; black and enamel-red burnet moths zoom past on a blur of wings; pink clovers grow in profusion; damselflies navigate the reeds like miniature helicopters; hawthorn flowers cover the hedgerow with their musky scent; scarlet poppies shimmer in the barley field beyond. It is a quintessential rural British scene, although it happens to be on my own land.

  There is nothing particularly unusual about any of these species. None of Britain’s rare butterflies live here, nor do any of the rarer dragonflies or damselflies, and there are no unusual bumblebees. Instead we have the sorts of species that you can see anywhere in the countryside. Some of the birds are scarce, but not many of them. Half a dozen tree sparrows, quite rare in Britain but abundant human companions in Tokyo and in the towns and villages of Borneo, are chirping in a bush. As for the ponies, wild horses may be endangered these days but 58 million of their domesticated descendants are still alive. Scanning my land, a naturalist might glance and then move on: these are just ordinary species that you might find anywhere else in Britain.

  So, how many are there? I have counted twenty-two butterfly species, fifteen types of dragonflies and damselflies, ninety-two bird species and nineteen different kinds of mammals living on the land, or at least visiting occasionally. For each of these groups, these numbers amount to between 30 and 40 per cent of all the species regularly found in Britain, which is remarkable, considering that the area of the land is only just over two hectares, or 5.5 acres in old money. That is to say, a third of all British species can be observed in a plot one-millionth of the area of Britain. If we want to go global, four out of every thousand species on the planet can be seen on a billionth of the world’s land surface. What is odd about this is that all these species are living in a thoroughly human-changed landscape that bears almost no resemblance to the pre-human habitats that used to be here.

  Instead of primeval forest inhabited by straight-tusked elephants and rhinoceros, I have hedgerows, a shelter-belt containing a mixture of tree species that I planted in the year 2000, three small meadows that are grazed by ponies and cut at different times of the year, some bushes, an occasionally dry ditch, a regularly mown lawn, flower beds and three small ponds created using butyl liners. The surrounding countryside is the Vale of York landscape of wheat, barley and oilseed rape. It is a human-dominated world. It seems quite extraordinary for such a small piece of land that is so unlike any ‘natural’ vegetation that might once have existed in the region to support such a high proportion of the country’s animal species, and a surprisingly high proportion of the whole world’s species. And few of them are the same species that would have lived in the original forest. This corner of Yorkshire is populated by opportunists of the Anthropocene.

  Before drawing any general conclusions about the extent to which species are surviving, and thriving, in human-altered habitats, we need to contemplate other parts of the world. And where better to start than in a tropical forest? A blur of red, yellow and blue stands out in sharp contrast to the green forest trees, as scarlet macaws squabbling over the flowers of a balsa tree screech like drunken teenagers. Capuchin monkeys cautiously reach to pluck fruit from the slender branches of nearby guavas, caterpillars of brightly painted Heliconius butterflies nibble tendrils of granadilla passion vines whose exquisitely purple-filamented flowers hang like aerial jellyfish, and banana-like clumps of ‘lobster-claw’ plants glimmer and buzz with hummingbirds. Malodorous peccary herds pass by, sniffing out the fruits that the capuchins dropped, while lolloping cane toads guard the toilet block. I observe this tropical scene from the comfort of a deckchair, sitting on the veranda of the Sirena ranger station in Corcovado National Park in Costa Rica, one of the world’s great wild places. It’s an ideal spot to sit and admire the wildlife, sticky-tape in hand, dabbing off the ticks acquired from a day in the forest. It is hardly surprising that Sirena’s 310-strong bird list is over three times longer than my own from home: a full 3 per cent of the world’s bird species in one place. The park’s 140 mammal species also constitute some 2.6 per cent of the world total. It seems like an almost unnecessary diversity, in an apparently more natural environment.

  At the height of the wet season in November, Corcovado is humid enough for your clothes to moulder and smell as you suspend them under the roof in the vain hope that they might dry, which I did when I became stranded there just over thirty years ago, an unshaven, mirror-deprived graduate student with the wispiest of beards. On this particular visit, bottle-green wild muscovy ducks paddled in the shallows of the waterlogged landing strip, the deluge rendering Sirena’s airborne supply route unusable for weeks. The trail to Los Patos was a twenty-kilometre quagmire, impassable for the park’s ponies, which stood forlornly, soaked, licking their wounds. The vampire bats had been at them again in the night. The rivers along the coast were in full spate and blocked our way to the north, but we did not fancy a trip south, where bands of illegal gold miners were in occupation. With all exit routes barred, we sat it out, ‘we’ being a small group of PhD students from the University of Texas, as well as Don Nilo and several other park guards. We could cope for a while, on a diet of ri
ce, beans and spaghetti, until the beans ran out, and then the spaghetti, and then it was white rice alone. As our energy levels dropped, we entered a state of diet-induced lethargy. Finally, one of our number, Taiwanese student Peng Chai, had had enough.

  Starting at dawn, Peng’s first task was to catch insects to feed to his hand-reared jacamars, the subject of his doctorate. These astonishing birds sport a coat of shimmering, metallic green feathers and a rusty belly. Their outsized tweezer-like bills are used with great dexterity first to capture flying insects and then to disarm wasps of their stings, to remove the indigestible wings of dragonflies and to inspect butterflies before deciding whether they are sufficiently tasty to consume. With his avian babies fed, Peng marshalled the troops, handing out instructions for gathering fruit: guavas, two types of passion fruit, oranges, plantains, palm fruits and relatives of the chilli pepper of dangerous potency. There was also a relative of black pepper to be found growing beneath the forest canopy, ginger to be dug, crayfish to be netted from the stream, snails from rock pools and fish from the Rio Sirena, where you had to dodge the odd crocodile and bull shark. Add to these ingredients Taiwanese culinary skills, and an array of exciting concoctions was spread before us. Our spirits were lifted, like a miracle.

  None of us did any research that day, mind you. So, how did a bunch of inexpert foreigners do, when asked to become hunter-gatherers for the day? We all knew the forest well, but our lack of expertise was all too apparent. Peng and his motley crew managed to gather enough food to repay the energy of collecting it, but only because there was a ready supply of guavas, granadilla passion fruit, citrus, plantains, ginger, palm fruits and coriander, all remnants of the former life of the Sirena station. We were living in a forest that used to be a farm.

  Sirena brims with wildlife, but it is not pristine. A previous owner of the main finca–the wooden, colonial-style farmhouse that subsequently became the park-ranger station we inhabited–had kindly planted out most of the bounty that we harvested. Sirena’s abundant wildlife was living in a landscape with a past history of hunting, active farming, livestock grazing and cutting of timber. Fewer of those fruit trees survive today as the farmland is gradually swallowed and reclaimed by the encircling forest, but the vegetation and its associated animals reflect this history.

  Wild passion vines that benefit from extra sunshine at the human-cut forest edges are sought out by butterflies looking for somewhere to lay their eggs. Fruits of the granadilla passion vines, which had initially been fostered by the farm, are consumed by agouti, long-legged rodents with exceedingly sharp teeth. The planted guavas attract monkeys, peccaries and eye-spotted forest butterflies that suck juices from fallen rotting fruits. Fast-growing balsa trees spring up on the farm’s former pastures, feeding the macaws, beneath which coral-orange lobster-claw flowers form an iridescent under-storey, whirring with hermit hummingbirds. The crumpled leaves of willowy, light-demanding Cecropia trees that sprout by the side of the human-maintained runway are unfurled by squirrel monkeys seeking tasty insect morsels. Some species, like the macaws, just visit to snack in the former farmland, but the squirrel monkeys, some of the wild relatives of capsicums and their associated clear-winged butterflies, and striped zebra butterflies that are beloved by keepers of butterfly houses in North America and Europe, are barely seen at all in the denser forest beyond. Numerous species owe their presence–or at least their abundance–to the habitats created by the previous human presence.

  There is a long history of human occupation in this region. Up to two metres wide and fifteen tonnes in weight, the remarkable stone spheres that were left by the ancient Diquís culture were hewn from dense gabbro rocks. No one knows quite why they were created, but whatever their original function, they speak to us of a pre-Columbian culture in this part of Costa Rica that was capable of monumental feats. These feats included farming the river valley directly inland from Corcovado National Park for a thousand or more years.1 The Diquís bordered on the maize-growing Aguas Buenas and, later, Chiriquí cultures of western Panama and southern Costa Rica, which were established from AD300 onwards. Farming is not a recent event in this part of the world, or in most other places. Far from being a pristine rainforest, the human-associated wildlife that we enjoyed at Sirena has been adjusting to disturbance by humans for thousands of years.

  The same is true elsewhere. Agriculture developed in Mexico as early as ten thousand years ago. Over the following several thousand years, cultivation was established throughout Central America and in a band across the northern parts of South America.2 By six thousand years ago, agriculture was practised in the Andes and southern Amazonia. Millennia later, the conquistadors rode through farmers’ fields more often than they hacked their way through virgin jungles. Tilling the land and pastoralism began between thirteen thousand and ten thousand years ago in the Middle East, and has also been widespread in Europe and northern Africa for many thousands of years. Cultivation of broomcorn millet started in the Huang He basin of China around ten thousand years ago, and the inhabitants of Southeast Asia later transformed entire landscapes into terraced wetlands for the cultivation of rice. Further east, the mountain tribes of New Guinea have cultivated their farms and gardens for nine thousand years, surrounded by the forests where they still hunt. In Africa, too, agriculture has a long history. Ethiopia was home to a succession of humanity’s distant relatives, culminating in the evolution of our own species two hundred thousand years ago. Despite millions of years of hominid history, and despite having been an important centre for the domestication of crops for thousands of years, Ethiopia is still rich in animals and plants found nowhere else on Earth.

  Not only are these transformations ancient but they are truly global. North American hunters used fire to manage forests and grasslands, as did Australian Aboriginals. The coastal forests of Okomu National Park in Nigeria are strewn with historical artefacts of previous human occupation; what was once thought to have been pristine forest has regenerated in the past seven hundred years, growing on a bed of charcoal. Fast-forward to soya farms in Brazil, agricultural prairies in Kansas, wheat fields in parts of Russia, enormous Australian sheep paddocks and silage production in sown pastures in northwestern Europe. Humans have created a cornucopia of new habitats, and have done so for millennia across six continents. This has created a world of new opportunities for those animals and plants capable of seizing them.

  That so many species now live alongside us in human-modified environments, whether on intensive farmland in Britain or in regenerating forest in Costa Rica, is not to say that any human society, past or present, has ever lived in ‘harmony’ with nature. This is absolutely not the case. The harmonious coexistence of humans and the rest of nature in the distant past is a romanticized and largely fictional notion. Present-day conservation often attempts to re-create these idealized ecosystems, for example by the reintroduction of hunter-gatherer-style burning of vegetation in America, Africa and Australia, and by reinstating now uneconomic medieval farming and forestry practices in Europe and Asia. In truth, our relationship with nature is, and always was, less romantic. We eat nature. We take up space that wild nature would otherwise occupy. We have used whatever technologies have been available to us at a particular time to consume or oust wild creatures, often with great success. As a consequence, we are living through a time of extinction.

  It is important to consider these losses of wildlife, particularly those associated with the conversion of so much of the world’s surface to human ends, if we are to put the successes of the opportunists into perspective. Once we convert the previous vegetation to cereal fields and concrete, there is less space left over for the rest of nature. One way to estimate the impact of these changes is to apply the so-called ‘species–area relationship’ to the loss of the original habitat. This relationship tells us that the number of species declines when the area of any habitat is reduced; for example, relatively few forest birds live on the smallest wooded islands that can be found off
the coast of Brazil.3 These islands became isolated from the mainland when water levels rose at the end of the last ice age, 11,650 to 7,000 years ago, and so they provide insight into how many forest-dependent birds might survive in the long run, if we were to convert a continuously forested landscape into one in which there are ‘forest islands’ surrounded by an ocean of sugar-cane fields and pastures. This is, of course, exactly what we have done. The species–area relationship tells us that we can normally expect somewhere between 29 per cent and 44 per cent of species to disappear if 90 per cent of the original habitat is destroyed.4

  Armed with such species–area graphs, Tom Brooks from the International Union for the Conservation of Nature and Andrew Balmford of the University of Cambridge took on the challenge of estimating how many species might become extinct because of forest loss in the Atlantic region of Brazil. These Atlantic forests form a wet coastal fringe from the north-east to the southern limits of Brazil, extending into northern Argentina and Paraguay, and separated from the humid Amazonian forests by the dry, savanna-like ‘cerrado’ vegetation, which is inhabited by termite-eating giant anteaters and maned wolves. The cerrado is too dry for most Amazonian and Atlantic trees, so these two great forests and their inhabitants are kept apart, their long history of separation allowing the animals and plants of coastal Brazil to evolve into species that live nowhere else in the world. The golden-lion tamarin, woolly spider monkey, buffy tufted-ear marmoset, yellow-breasted capuchin, Barbara Brown’s titi, Southern brown howling monkey and Northern muriqui head up a long list of monkeys that are entirely confined to these forests. It is also the home of most Brazilians–São Paolo and Rio de Janeiro are bang in the middle of it. Not surprisingly, therefore, some 93 per cent of the forest has been cleared, principally for agriculture, and the region holds one of the world’s greatest concentrations of endangered species.