Conservation for the World We Want

Protecting Biodiversity Because We Can, Not Because We Must

When next you’ve a few spare moments to daydream, I recommend a visit to one of the Internet’s most fantastical sites: Wikipedia’s entry on what scientists call the “Late Pleistocene extinction event.”

The Pleistocene refers to the epoch between 2.6 million and 11,000 years ago, during which glaciers alternately expanded and contracted across the Earth’s surface. Arguably, the current geological epoch, the Holocene, is simply the latest episode of Pleistocene glacial contraction. However, the transformation that followed as ice sheets retreated and Homo sapiens proliferated certainly sets the Holocene apart.

Hundreds of species, most of them exceptionally large-bodied by present standards, ceased to exist. Giant armadillos and truck-sized sloths, woolly rhinoceros and land-dwelling crocodiles vanished. Camels and mammoths no longer trod North America. Hippos stopped wallowing in the British Isles. Vultures with 20-foot wingspans disappeared from South American skies. On and on the list of lost creatures goes, their legacy surviving only in museum dioramas and fairy tales—and, perhaps, in subtler ways.

After those animals went extinct, something strange appears in the fossil record, again and again, around much of the terrestrial world: a layer of charcoal. It doesn’t seem to be a coincidence. According to some paleoecologists, the sudden absence of big plant-eating animals made many of Earth’s landscapes more fire-prone.

Those animals, say the scientists, consumed fire-fueling woody debris. They grazed in patterns that created natural firebreaks. By rooting through the earth, they buried plant material that might otherwise have become tinder. Their countless incremental actions and interactions gradually made Earth a gentler, more life-filled place. This is still just a theory, to be sure, but a compelling one. And if giant sloths are now just an evolutionary memory, the big plant-eaters who remain — elephants and musk ox, moose and wildebeest, and so on — must still influence fire dynamics.

I wrote about this last fall for Anthropocene Magazine in connection with a research article that urged conservationists to consider protecting large herbivores as a landscape-scale fire prevention strategy. Just a few days earlier, the World Wildlife Fund released its latest Living Planet Report, a biannual review of Earth’s ecological status and humanity’s role in its diminishment. According to the report, wild animal populations have declined by an average of 60 percent in just the past several decades.

Its authors posit that climate change is partly to blame. Mostly, though, it’s human activity that’s fueled this obliteration, especially short-sighted development, food production, and overconsumption. And this loss is tragic, stresses the World Wildlife Fund, not only because something immeasurably special is lost when species dwindle, but because human well-being is affected, too. “Our health, food and security depend on biodiversity,” the report counseled. “All economic activity ultimately depends on services provided by nature.” Mike Barrett, one of the report’s coauthors, told The Guardian newspaper that wildlife declines are “actually now jeopardising the future of people. Nature is not ‘nice to have’ — it is our life support system.”

The WWF is not the first to make this argument. “Our food, our water, our livelihoods — they all come from nature,” proclaims the People Need Nature section of Conservation International’s website. “[S]aving nature is the only way to save ourselves.” Similar sentiments are expressed regularly in environmental circles, as when (to pick an unremarkable but emblematic example) a sustainable development manager at retail giant Marks & Spencer warned palm oil producers that “we need nature in order to survive as a species.”

Broadly speaking, these pronouncements can be understood as a public-facing distillation of decades of research on the relationships between the identity and functions of organisms; the biogeochemical patterns and processes their activities produce; and human interests. There’s no question that nonhuman nature does support human well-being; one oft-repeated estimate puts the total value of all ecosystem services at $125 trillion, and while that calculation’s particulars can be debated, it gets at the general principle. Yet there is something disconcerting, even problematic, about the slogan version of people needing nature.


A slogan’s purpose, of course, isn’t to capture nuance. But there are ways in which this save-it-or-die framing rankles, beginning with the fact that, at precisely the same time as so many wild lives are imperiled, billions of people are enjoying historically unprecedented prosperity and health. That is not to say that economic well-being automatically flows from nature’s destruction, or that future well-being requires it, but simply that it has not yet precluded human flourishing.

Returning to megafauna and fire, Earth is more fire-prone than it once was, but people have managed — not without suffering, often with difficulty, but managed all the same. The depletion of whale populations and terrestrial megafauna reduced nutrient flows from the deep sea and across landscapes to a trickle, but the consequences were not catastrophic for us. Indeed, the state of nature that conservationists hope to protect, and present in terms of human self-interest, has already been radically transformed from just a few thousand years ago — not just because of the late Pleistocene mass extinctions, but also because of the dwindling of what and who remains.

Global turtle populations, to pick one little-appreciated example, have collapsed. Not long ago they existed in densities that, in terms of total per-hectare biomass, often outweighed that of African savannah herbivores like elephant and giraffes. Now turtles “are struggling to persist in the modern world,” as a recent scientific review described their plight. “Their ecological roles are now greatly diminished,” and “The impacts of their lessened roles are poorly appreciated and inadequately understood.” Perhaps the loss of all that habitat engineering (many turtles dig burrows that are used by other creatures and contribute to long-term soil enrichment), seed dispersal, and nutrient cycling has diminished human well-being in significant ways, but it’s a hard argument to make right now.

It is possible, of course, that the effects of turtle decline — and amphibian decline and bat decline and insect decline and megafauna decline, and on and on — have not yet been fully realized, and that human societies are running on a biological “surplus” banked over hundreds of millions of years. By this light, just as people will eventually run out of fuels derived from whole geological epochs’ worth of fossilized plankton and vegetable matter, so might we exhaust soils nourished by organismal activity or air filtered by forest communities now missing animals who once planted their seeds.

Alternatively, one could argue that although even a diminished biosphere was enough to sustain human prosperity, the current 7.7 billion humans and 70 billion domesticated animals they exploit for food have pushed that sustenance to its limits. Taking these precautionary approaches, however, is not quite the same as directly equating human health, security, and prosperity with a recent snapshot of nature — especially when that version of “nature” is implicitly equated with biological diversity and abundance, and even as so much of what we take from the biosphere comes from simplified ecosystems.

Tree plantations still sequester carbon dioxide and exhale oxygen while generating wood. Defaunated wetlands still filter water and buffer against storms. Most of the food we eat comes from comparatively low-diversity croplands. Restoring, say, soil biodiversity to the plains of central North America, the world’s most productive agricultural landscape, is more about reducing chemical use and changing farming techniques to ensure their long-term productivity than returning them to their former prairie glory.

To be sure, these human-directed systems are often less multifunctional than higher-biodiversity systems. Monoculture tree plantations store less carbon than wild forests, and defaunated wild forests store less carbon than those with intact animal communities. But conceiving of engineered ecosystems in terms of resource yield and a few other metrics is terribly reductionist.

Arguably, the greatest service of all is the long-term stability that intact ecologies provide. Species interactions and functional redundancies help ecosystems — and ultimately the biosphere itself — adapt to environmental fluctuations, regrouping and supporting complex arrangements of life even when Earth’s climate changes or an asteroid strikes.

Yet that particular service isn’t one that maps neatly onto short-term human interests in wood production, clean water, or fisheries yield. And to casually say those benefits come from “nature” erodes, or at least blurs, what conservationists want to protect: forms of nature in which communities and processes found in the absence of humans remain largely intact, and where human activity doesn’t divert their yields without nourishing more nonhuman life in return. To view, say, the pollination of commodity crops by managed honeybees trucked cross-country as an example of nature’s bounty would be to diminish nature.


This critique is not intended to downplay the hardships caused by nature’s decline and destruction. The recent Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) report, which estimated that one in eight species of plants and animals is now threatened with extinction, enumerates them well. Nature indeed “sustains the quality of the air, fresh water and soils on which humanity depends, distributes fresh water, regulates the climate, provides pollination and pest control and reduces the impact of natural hazards,” and the impacts of ecological disruption are felt most by people who possess the least.

Ultimately, though, human ingenuity can substitute for many of nature’s services. The results might be unpleasant in many ways — I’d much rather rely on bats and earthworms than pesticides and fertilizers — but they’re rarely an existential threat to human societies. The vast, fertilizer-fueled Gulf of Mexico dead zone is a horrible, shameful thing and has inflicted hardship on many people, but southeastern U.S. coastal communities have not collapsed because of it.

Some people, such as those who work in small- and large-scale fisheries, or the roughly two billion people who rely on subsistence-harvested wood for fuel, do depend intimately on various forms of rich nature. But many more do not. Protecting nature in order to support the well-being of those nature-linked communities is essential — both as a matter of human decency and because, at least for the foreseeable future, an abundant Earth will necessarily contain large swaths devoted simultaneously to human sustenance and natural richness. However, this is only part of the solution.

The IPBES report rightly calls for “transformative changes across economic, social, political and technological factors.” A central challenge, though, is not to protect natural richness so that human societies might prosper, but to disentangle prosperity and economic well-being from resource consumption so that natural richness can remain abundant.

This isn’t a matter of simply increasing efficiency and productivity, but of envisioning economic growth and prosperity that isn’t resource-intensive. It means envisioning a society that is not so reliant on displacing and consuming other lives. Claiming that “all our economic activity ultimately depends on nature,” as does the WWF, normalizes a biosphere-impoverishing state of affairs and threatens our ability to imagine other ways of thriving. Just imagine if commercial whaling were defended on the grounds of fuel security.

All of which is uncomfortable to say. It’s unpleasant to consider that we don’t necessarily need biodiversity, at least not in such a simplistic way. The convergence of human interests and the biosphere’s flourishing makes for a seemingly powerful argument — one that doesn’t require a change of heart in people who don’t already care much about nature. Arguing instead that a nature-rich Earth will require most people to divorce economic growth from resource consumption while accommodating a few traditional-use cultures and low-yield, high-biodiversity systems (such as timber farms managed to mimic climax forests) isn’t nearly so simple or inspiring. But it is perhaps closer to the truth.

And I worry that oversimplifications could backfire. What happens when the last northern white rhinoceros dies but nothing seems to change? Can anyone really argue convincingly that we’d be healthier and wealthier if Steller’s sea cows and ivory-billed woodpeckers still existed? Also, there is something disconcertingly ahistorical about the emphasis on nature’s primacy to human well-being.

When I read that modern society owes everything to nature, I think of people who risked their lives to fight for living wages and humane working conditions. And what of the incredible sacrifices underlying modern liberal democracies, with their hard-won social safety nets, proscriptions against racial and sexual discrimination, contract law, and institutions? Or more fundamentally, their ethics of forgiveness, generosity, and open inquiry? I doubt that anyone who preaches nature’s importance to humanity would insist that such social progress relies more on biodiversity than on human struggle. Still, that’s what a literal reading of the slogans implies.

It’s far better, I think, to argue that Earth’s inhabitants, human and nonhuman alike, deserve to flourish simply because they’re wondrous: because they’re alive, and each lineage, each life, is valuable and good and deserves to be. And when our own well-being intersects neatly with biological diversity and abundance, then by all means we should embrace that — but in a clear-eyed way.

Which brings us back to the notion that big plant-eating animals make landscapes less flammable. The study I covered was part of an entire journal issue devoted to scientists considering the benefits of rewilding landscapes with lost animals, or at least their relatives. The researchers suggest that, in addition to regulating fire, those animals could help ecosystems sequester more carbon, reduce the impact of human-transported invasive species, fertilize streamside forests, enrich soils, and regulate unpredictable responses to climate change. And although it wasn’t covered in these studies, one could also have added biodiversity’s disease-regulating effects. Biologically rich communities often slow the spread of pathogens and their vectors.

All these aspects of biodiversity might make humans more prosperous. They would certainly make Earth more hospitable, and more lovely, even if our survival did not depend on it. In the end, humanity may actually flourish on an Earth with many fewer plants and animals — we are nothing if not adaptable. But that would be a barren and squalid place indeed.