Live, or Let Die?
On June 24, the last Galápagos Pinta Island tortoise of the subspecies Chelonoidis nigra abingdoni collapsed during a trip to his watering hole and died. Lonesome George was only 100 years old -- which is actually middle-aged for a tortoise -- and his death (from a heart attack, it was later concluded) shocked and saddened his many fans around the world.
Over the years, millions of tourists had flocked to the Charles Darwin Research Station where George lived to catch a glimpse of this reptile, who had refused to reproduce despite 40 years of matchmaking efforts by his caretakers -- making him literally the last of his kind. George's longtime keeper, Fausto Llerena, described him to the New York Times as a friendly soul who greeted workers each morning by moseying toward them, stretching out his neck, and opening his mouth. "To me," Llerena said, "he was everything." To news outlets from New Zealand to India to Scotland, he was irresistibly symbolic. He had been "a poster boy for conservation and endangered species," Scientific American noted; his death, as the Times put it, gave "extinction a face." Calls rang out for humanity to learn a lesson from his death. "We must all take action," an impassioned editorial in the Huffington Post declared, "so that this situation doesn't happen again."
But can the story of Lonesome George really help us solve the global crisis of extinction? Or is it possible that giving extinction an individual "face" actually prevents us from asking the kinds of uncomfortable questions that might significantly improve our larger conservation efforts?
Staggeringly, of the nearly 64,000 species currently on the International Union for Conservation of Nature's latest Red List of Threatened Species, nearly 20,000 are considered to be hurtling toward extinction: 41 percent of the amphibians, 30 percent of the conifers, 25 percent of the mammals, and 13 percent of the birds. Our epoch, the Holocene, is hosting what many scientists believe to be the world's sixth mass extinction. Scientists recently predicted that were we to lose all of these threatened species in the next 100 years -- as a result of habitat loss, climate change, invasive species takeovers, and hunting -- we would be on track to lose 75 percent of all known species within a few hundred more. As the party responsible for setting in motion this grand-scale extermination, we humans now face the terrifying question of what to do about it.
How do we decide which species should be first in line to receive our limited conservation funds and time? At the moment, we tend to regard as especially "valuable" those animals that, like George, are sizable and easy to anthropomorphize. We gave George a gentleman's name and personality and felt empathetic toward him: he was unlucky in love, amiable, affectionate toward his keepers, noble in his solitude. He looked great on a poster or T-shirt.
But when we donate money to save charismatic species like tortoises -- whether that means putting them behind glass in zoos or roping them off in preserves -- do we risk ignoring entire classes of protection-worthy organisms with lower public profiles? Recent studies suggest, for example, that ocean warming and acidification are threatening some of the nearly invisible phytoplankton that float on the lowest rung of the marine food chain. If you paid to see one, you'd need a microscope to get your money's worth. It would be difficult, to say the least, to conjure sympathetic thoughts or feelings from the plankton's appearance or behavior. But if phytoplankton were to disappear, we'd lose the zooplankton that eats it, the fish that eat the zooplankton -- and every sea creature that relies on fish.
Of course, conservation organizations don't take up the cause of a creature like George just because he's adorable. One of the most powerful pieces of environmental legislation in the United States, the Endangered Species Act of 1973, prioritizes plants and animals that scientists and policy makers have determined, through systematic surveys, to be nearest to vanishing; globally, similar criteria underlie the Red List. But these lists presume that the value of a species lies in direct proportion to its scarcity. Indeed, it was George's rarity as the sole remaining member of his line that helped make him a cause célèbre.
Every species is precious. George represented millions of years of evolutionary honing that's now gone, along with his power to enrich the beauty of nature and any medical secrets his DNA might have unlocked. But in purely practical terms, does fighting hardest for those species that are almost gone do the greatest good for the greatest number? When honeybees began mysteriously dying off in 2006, many were surprised to learn that honeybee pollination is responsible for nearly a third of the food that Americans eat. But pollinators and other insects are difficult to count in the wild -- a major reason they're rarely considered for endangered-species listing. We knew about the honeybees' plight, and were able to search for ways to help them, because we keep domestic colonies and could observe their decline. But are there other threatened populations of insects, fungi, or scavengers out there that similarly don't present us with a clear head count, and consequently don't meet our requirements for an endangered-species listing, but are nevertheless so vital to their ecosystems that they merit action? Wouldn't our limited time and money be better spent trying to figure out which species -- regardless of their numerical status -- are most critical to their respective habitats to begin with?
Recent forays into ranking the importance of species within ecosystems have yielded striking projections. In a 2011 study published in Nature, researchers set up grassland ecosystems with different numbers of plant species in each, observed them at length, and concluded that 84 percent of the species contributed in some indispensible way to the overall effectiveness of the ecosystem -- suggesting that 16 percent of them might be expendable. A review in Science revealed that certain top predators and large herbivores may have disproportionately heavy impacts on the health of their ecosystems compared with other species down the food chain. Thus has the overfishing of sharks along the Atlantic coast, for instance, led to a boom in rays and smaller fish and a corresponding decline in scallop and oyster populations. Similarly, in East Africa, the overhunting of buffalo and wildebeest has let vegetation grow unchecked, fueling more and larger wildfires.
But understanding how our ecosystems work is more complicated than simply knowing who is eating whom, or what. Animals and plants communicate via sounds, smells, and chemicals to relay complex messages we haven't yet decoded. In addition to that, only about 1.2 million species of flora, fauna, and fungi -- approximately one out of every seven species that recent estimates suggest exist on our planet -- have been counted so far. If we want to tag species with an ecological "value," we'll need to understand better the roles each plays in a given environment (see "GPS for Critters").
Which means we'll need to be ready -- and willing -- to recognize that many of our most beloved endangered species may no longer be fit, in the Darwinian sense of the word, to inhabit the places they once did. Currently we're fighting valiantly to save the endangered polar bear, whose Arctic habitat is in imminent danger of disappearing. We hope to win. But what if the unthinkable were to happen, and we lost? What if the Arctic's summer ice is gone within the next 25 years, as is often projected? Are we spending enough time thinking about which species will be best equipped to step into the polar bear's niche in what will by then have become a new Arctic ecosystem?
In the Galápagos, Lonesome George is being stuffed for display in a tortoise museum -- where he'll perform an only slightly reduced role in sustaining his environs than he did during his life. If we can stand to acknowledge that fact, and if acknowledging it buys us the freedom to improve the overall health of the earth's ecosystems, George's death will truly have taught us some valuable lessons. First, that the definition of a vibrant, sustainable ecosystem simply can't be what it was 50 years ago. Second, that we will have to make do with less. And third, that deciding which species we can afford to lose will be complicated, painful -- and necessary.