SEPTEMBER 16, 2015
NATURE IS IN TROUBLE — thanks to humans trampling over its domain, poisoning and felling it, and messing with the climate. But how much trouble? And how should we respond to help “nature” fight back? Should we cut ourselves off from nature or find ways to better integrate ourselves within it?
Ecologists Gerardo Ceballos and Paul and Anne Ehrlich insist nature is under siege and must be protected from us. This is war. “Humanity has unleashed a massive and escalating assault on all living things on the planet,” they begin The Annihilation of Nature. We are in the midst of the “sixth great extinction” — the worst ecological crisis since the asteroid hit that killed the dinosaurs and much else 65 million years ago. It is a tragedy that “may also be a harbinger of the end of our global civilization.”
Their heavily illustrated and lavishly produced book catalogs the plight of dozens of birds and mammals that are either in trouble or already extinct. A sorry tale, rich in detail, it acquaints us with the last moments of several species: the final Falkland island fox was killed on the South Atlantic islands in 1876; the Tasmanian tiger — a coyote-like marsupial from Australia — disappeared when its last survivor succumbed behind bars in 1936. We even learn that the final passenger pigeon, which died in a Cincinnati zoo in 1914, was called Martha.
The authors make an unabashed and heartfelt plea for going into battle on behalf of nature. No holds are barred. “To gain support for conservation initiatives […] it seems essential to communicate to the public and politicians the emotional side of the plight of biodiversity and to connect that predicament to human well-being,” they say.
But could their call to arms, and their frank appeal to “the emotional side,” be hurting their case?
Older readers will perhaps remember that almost half a century ago co-author and longtime Stanford stalwart Paul Ehrlich introduced us to the human “population bomb.” His book of that name, which sold millions of copies, warned that “billions will die in the 1980s” as food supplies ran out. It never happened because, even as he was writing those words, scientists were developing “green revolution” crops that kept pace with population growth, doubling world food production in a generation.
Maybe he is at it again. In truth, we have very little idea about the rate at which species are being lost, or the threat this may pose to how nature works. Scientists at the UN Convention on Biological Diversity, using modeling studies, put the loss at up to 150 species a day — out of a total species stock estimated at several million. But according to a database compiled by the International Union for the Conservation of Nature (IUCN), only about 800 actual extinctions have been recorded over the past 400 years. That is one every 150 days, rather than 150 every day.
If anything, recorded losses are diminishing. Most of the major extinctions happened before modern times. The megafauna of North America and Australia were wiped out thousands of years ago; the hundreds of species of land birds of the Pacific went extinct hundreds of years ago. The number of birds and mammals that are known to have gone extinct between 1980 and 2000 is just nine. This year, the IUCN reported no further extinctions of any species, though last year it confirmed the demise of a Malaysian snail and an earwig on the Atlantic island of St. Helena. This hardly constitutes a holocaust.
Of course the records are very incomplete. Many insects and other smaller critters are doubtless disappearing unremarked. But just as Ehrlich’s population warnings have proved ill-founded, so have the predictions of many ecologists.
In the 1980s, ecologists developed a simple formula they called the “species-area relationship.” They argued that the number of species in a particular habitat could be derived from the area of that habitat. Big areas held more species, and if you halved the area, half the species would disappear. This formula became the basis for apocalyptic warnings about the impact of the massive destruction and fragmentation of rainforests, where a large proportion of the world’s species are thought to live.
Half the world’s rainforests have now disappeared; but, despite the predictions, half the world’s rainforest species have not disappeared. As Australian ecologist Nigel Stork has pointed out, “there are almost no empirical data to support estimates of current extinctions of 100, or even one, species a day.”
In other words, species appear to be much more adaptable than supposed. Faced with the loss of their patch of forest, they don’t necessarily roll over and die; they adapt or move, finding new food sources and shelter. Claude Martin, who ran the environment group WWF International for more than a decade until 2005, noted in his recent book On the Edge that while El Salvador has lost 90 percent of its forests, only 3 percent of its 500 forest bird species have disappeared. A similar diminution of the giant Atlantic forest in Brazil has seen no bird species losses at all — making nonsense of the claim in this book that “one-third of the tree species in Brazil’s Atlantic forest may go extinct in the future, due to the loss of avian dispersers.”
In their desire to underline the urgency of species loss, Ceballos and the Ehrlichs seem to be in denial about such findings. To be sure, they may be right that some species are in terminal decline as a result of lost habitat. But, as Smithsonian forest ecologist Stephen Hubbell says of his own researches, “more species always remained than were expected from the species-area relationship.”
Instead of reappraising their alarmist take, the authors resort to hectoring and anti-scientific rhetoric. “Some people claim that the seriousness of the extinction crises is overestimated — intellectually the equivalent of claiming that a beach eroding away before one’s eyes isn’t disappearing because the number of grains of sand on it […] haven’t been counted.” No, “counting the grains” is doing sound science.
Perhaps a little hyperbole is acceptable if the future of nature is at stake. But I believe it can be dangerous, and even defeatist, because it reinforces a false antagonism in which we humans are seen as the enemy of nature. “More people equals fewer species,” the authors say. From this perspective, the assumption is that the only way to protect nature is to sequester it behind fences in national parks where conservationists are king and the rest of us are excluded.
But in the Anthropocene — the era we have now entered, in which humans dominate the planet — this “fortress conservation” approach is neither feasible nor, I believe, desirable.
For one thing, much as we might like to believe it, very few areas of the planet are remotely pristine. Even the Amazon rainforest, accounting for our most cherished image of the virgin jungle, turns out to have been transformed by pre-Colombian societies that built cities, mulched and drained soils, and planted millions of palms and nut and fruit trees. “Few if any pristine landscapes remained in 1492,” Charles Clement of Brazil’s National Institute of Amazonian Research concluded recently. “Many present Amazon forests, while seemingly natural, are domesticated.” What we see today is the world’s largest overgrown garden.
We might bemoan this transformation, but surely the good news is that keeping us apart from nature is not as important as it once appeared. If the Amazon remains, as ecologists claim, just about the most biologically diverse place on the planet, then that says a lot for how humans and nature can co-exist.
Most of the planet’s ecosystems are what some ecologists now term “novel ecosystems” — mixtures of native, planted, and invader species. These thriving ecosystems challenge the conventional vision of nature as made up of unimaginably complex systems of interdependent species that have evolved together over long periods of time.
It seems that most of nature is not perfected and fragile; it is temporary, haphazard, and adaptable. Arguably, change is what drives nature to innovate.
Ceballos, whose research base is the National Autonomous University of Mexico, briefly recognizes this. He notes at one point that “flux is the natural state of the world.” But he does not follow the logic. If change is the essence of nature, he cannot be right to argue that any extinction is “catastrophic” simply because “the universe is unlikely ever again to see that particular collection of genes.”
Conservation that sees its overarching goal as protecting individual species and allegedly pristine ecosystems is little more than ecological antiquarianism. In the Anthropocene, we instead need to develop a new vision of conservation that acknowledges nature’s dynamism and ability to change and adapt. How else do we expect nature to get by in an era of climate change?
This new approach will find its rationale in how nature prospers in human landscapes, including our densely populated cities, with their many different niches and habitats, some unlike anything found beyond a given city’s limits. In my native England, most bees and butterflies are now urbanites. One derelict oil terminal near me contains 1,300 species per hectare, more than any nature reserve. Yet conventional conservation ignores such places.
We catch glimpses of the potential of such Anthropocene ecologies in this book. For instance, it narrates how the famous mountain gorillas of Rwanda live not in remote jungle but within earshot of villages where dogs are barking and radios blaring. Ceballos calls this conjunction “a strange mixture.” But it is far from unique. Many of Sumatra’s last tigers roam among plantations of oil palms, and European wolves are colonizing the suburbs of Germany. This is the new normal, and one we should embrace. The urban jungle may turn out to be more than a metaphor.
New ecologies of this sort also require us to rethink our antipathy to alien species that thrive outside their “native” habitats, often after being transplanted by humans. Ecologists such as Ceballos call them the second greatest threat to nature, after habitat loss. The aliens stand accused of causing widespread extinctions among native species. But this, too, is simply not true.
Yes, there are horror stories, like the brown tree snakes eating their way through the bird populations of Guam. But as I argue in my book, The New Wild, species introductions almost always add to local biodiversity. Ceballos notes in horror that in the grasslands of California, introduced animals and plants comprise 60 percent of biodiversity. But so what? Across America, the arrival of some 4,000 plant species from Europe has increased US plant biodiversity by a fifth, with only a single recorded native extinction.
In fact, by offering new adaptive possibilities for ecosystems, alien invaders may prove to be nature’s salvation in the 21st century. To take one small example: Climate change has deprived migratory birds in New England of their favorite autumn food, because the hot summers make native blueberries and huckleberries ripen early and die off weeks before the birds are due to head south for the winter. So now the birds rely on alien honeysuckles and oriental bittersweet, which fruit for longer.
Finally, I believe fortress conservation is mistaken because it turns people into enemies of nature. In the cause of conservation, millions of native people and forest dwellers have been thrown off their lands in recent decades to make way for protected areas. Yet the evidence is that such people are mostly better at protecting nature — by living alongside and nurturing as well as exploiting it — than state parks that frequently become lawless places, overrun by loggers, miners, and others.
Take the Brazilian Amazon. In the past quarter-century, the government there has established about 300 indigenous territories where tribes can use their forests for their own needs, and can exclude outsiders. Today, deforestation in indigenous areas is only a tenth of that outside these areas, because tribes such as the Yanomami and Kayapo have successfully defended their forests against invasions.
This “use it or lose it” approach to conservation offers huge potential dividends for nature. A forest with people in it may not be the “pristine” environment that many ecologists yearn for. But it is where nature and its biodiversity will thrive in the 21st century. By promoting a siege approach to conservation, in which humans are the enemy, books such as The Annihilation of Nature are part of the problem, rather than part of the solution.