Source:Current Biology, Volume 20, Issue 12, R493-R495
The last tortoise
The Last Tortoise Craig B. Stanford The Belknap Press of Harvard University Press. ISBN: 978-0-674-04992-5
The UN used World Environment Day earlier this month to launch a report highlighting the problems facing the conservation and management of biodiversity in the face of the many assaults humans are making on the natural environment.
The report — Dead Planet, Living Planet; Biodiversity and Ecosystem Restoration for Sustainable Development — highlights not only the preservation of natural ecosystems but the value of investment in degraded systems that can bring about economic benefits.
The report marks the year 2010, which was the target for a range of biodiversity goals set almost two decades ago by the UN's Convention on Biological Diversity.
The achievements are generally disappointing, with just individual success stories lightening the assessment (see page R496–R497). And what is becoming increasingly apparent is the lack of haste in the face of ever-quickening environmental and ecological change. Under current circumstances, two decades of unsatisfactory results is time that can barely afford to have been lost. Some researchers are now talking about a sixth wave of mass extinctions, almost wholly the result of man's activities, and one group of animals highlights this prospect and the wider problems worldwide that face conservationists.
A new book, The Last Tortoise, by University of Southern California biologist, Craig Stanford, looks at the lessons these often neglected animals present for researchers. “Tortoises and turtles are at the forefront of the global battle to prevent an imminent mass extinction,” he writes. Every year more than 10 million tortoises and turtles change hands in Asia — tens of thousands per day.” Most of these are taken from the wild or smuggled openly across the borders between the nations of southeast Asia and China. They may have been smuggled first from Indonesia or Malaysia into these border countries. “The border, so ironclad when it comes to military issues, is just a porous membrane when illegal trade in wild animals or their parts is involved.”
The trade in live turtles bound for the Chinese food markets is worth an estimated 700 million dollars annually. And such is the effort of gatherers, there are several varieties of turtles in China that have never been seen in the wild; their existence is known only from the few of the last surviving individuals that are spotted in markets. “A conservationist who visited one such market in the late 1990s estimated at least ten thousand turtles, most of them taken from the wild, for sale in that market alone,” he writes.
Stanford is plangent in celebrating the extraordinary biology and evolution of these fast-disappearing animals. “They have managed the astounding evolutionary feat of relocating their shoulders and hips inside their ribcages and placing a huge protective shield upon their back. Following this radical achievement of anatomical shape-shifting, they have stuck with the program for more than 200 million years. There is no other backboned animal that combines such a unique set of adaptations with a stay-the-course approach to evolutionary success.”
Tortoises have among the most extraordinary life cycles of any animal on earth. Few if any backboned animals live longer — more than a century and a half. “They may remain as physically spry and reproductively able at a hundred as at twenty, a feat that scientists are struggling to understand. Although the giant tortoise species typically live the longest, even small turtles and tortoise species routinely live more than a half-century,” he says. “This life-in-the-slow-lane approach is one of the factors that has made existence precarious for tortoises and their kin. A slow reproductive strategy may have advantages in the wild under the right circumstances, but when people are collecting you, eating you, and cutting down your habitat, it's an albatross around the neck.”
Although eating turtles and tortoises is an ancient practice in many East Asian countries, in recent years the combination of explosive population growth and newfound consumer cash has created an environmentally destructive force. A practice that may have been sustainable amongst scattered peasant or gatherer communities has now translated into big business. “Wholesale food companies in China have standing orders in Indonesia, Malaysia, and other countries for thousands of pounds of turtle and tortoise meat per week,” he says.
Those species that are not gathered for food or the pharmacy shelves are taken by the thousands for the global pet trade. “Some of the trade is perfectly legal, if inadvisable, the result of the developing world's eagerness to turn a profit on its natural resources,” he says. But much of the trade is black, illegal. “A villager in Madagascar for whom a dollar is a day's salary can take a radiated tortoise, resplendent in its starburst shell, and sell it at a profit of five dollars to a local middleman. That tortoise will be smuggled in a suitcase or false-bottomed crate to a distribution point in Asia, perhaps Singapore or Bangkok, and then onward, to be bought by a collector in Europe, North America or Japan for five thousand dollars.”
Such enormous sums only increase the pressure on these species and increasing rarity only adds to their value. “Turtles and tortoises have become a global trade item. In the case of the rarest and most beautiful species — and therefore the most valuable — the black market profits to be made may in some cases rival those from the global trade in narcotics.”
Stanford warns of the speed and extent of loss of these animals in the face of such onslaughts. And even where they are not being directly targeted, habitat loss is adding additional pressure. “There are many countries in Southeast Asia that have for millennia been centres of biodiversity which are now emptied of their entire tortoise and turtle fauna. Vietnam is almost devoid of its many species of native tortoises and freshwater turtles — they've all gone to markets in China. Laos, Cambodia, Myanmar and Indonesia are close behind,” Stanford says. Conservationists refer to China as the “black hole” of wildlife conservation for its ongoing appetite for the animals of the entire Asian continent. A nation and an industry hungry to supply an ever more affluent society of tortoise eaters and pet-keepers will not be denied.
People often worry about the legacy, environmental and otherwise, they will leave their children and grandchildren. Stanford makes clear that several tortoise species are unlikely to last that long and will be driven to extinction in a shockingly few number of years. But he points at a few glimmers of hope. Thais, like other Asians, have traditionally eaten tortoises, but there is some encouragement from the Kaeng Krachan National Park in the south-west of the country. This park is one of the largest in southeast Asia and is almost pristine. It is home to the largest population of tigers within a reserve anywhere, plus elephants and every other large Asian mammal species. But it is also a stronghold of the Asian forest tortoise, the largest Asian tortoise, which lives in the mountainous wet forests from eastern India through to Indonesia.
Middle-class Thais have embraced ecotourism on the western model, and visit the park to camp during the cool winter season, where sight of a tortoise, or any other species, is all that is sought.