MORE than two-fifths of Earth鈥檚 land surface is still wilderness, according to an unprecedented global survey published this week. This means it could be relatively cheap to preserve much of the world鈥檚 pristine wild habitats.
The report鈥檚 authors found that 44 per cent of Earth鈥檚 surface is little affected by human habitation, including great swathes of Siberia, Africa, North and South America and Antarctica. Although some of these vast areas support relatively few species, they could be a conservation bargain, since such sparsely populated land can be bought up and protected cheaply.
Even more attractive, the scientists say, are the 8.9 million square kilometres that contain the highest species diversity. Priority should be given to protecting these regions, which include New Guinea and the Congo forests of central Africa.
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鈥淲e were surprised how much of the planet remains relatively little impacted by people,鈥� says Tom Brooks of Washington DC-based charity Conservation International, a lead researcher for the survey published online in Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.1732458100).
The findings come just a month before governments and conservation experts convene for the 5th World Parks Congress in Durban, South Africa, a 10-yearly meeting to decide how to best protect the world鈥檚 wildlife and its wild habitats.
The researchers from the US and Brazil who conducted the global survey defined 鈥渨ilderness鈥� as large contiguous areas with no more than five people per square kilometre. Territories also had to contain at least 70 per cent of the same kind of habitats they had 500 years ago.
In all, 65 million square kilometres in 24 different areas qualified as wilderness (see Map). They include humid and dry tropical forests, tropical grasslands, warm and cold-winter deserts, mountains, temperate rainforests, tundra and Arctic deserts. Together, these areas are home to just 204 million people, or about 3 per cent of the total global population.
Only about 18 per cent of all known plant species and about 10 per cent of all known terrestrial vertebrate species are endemic to these wilderness areas. Nevertheless, low-biodiversity areas are worth conserving, the researchers argue. They can be bought cheaply 鈥� for about $10 per hectare, or about $50 billion in total. They also provide services for the entire planet, such as nitrogen fixation, pollination and carbon sequestration, as well as destinations for ecotourists. 鈥淔inally, there are strong aesthetic, moral and spiritual values of wilderness permeating all cultures and religions and providing a firm imperative for its conservation,鈥� the authors argue.
The wilderness proposal is meant to be considered alongside the biodiversity 鈥渉ot spots鈥� proposal first made by Norman Myers of the University of Oxford 3 years ago. Myers claimed that only 1.4 per cent of Earth鈥檚 land area contained 44 per cent of all plant species and 35 per cent of land vertebrates (快猫短视频, 26 February 2000, p 12). Conservation International and others have since argued that hot spots should be a conservation priority, but critics say that could lead to the neglect of other areas worth preserving.
The new proposal says that alongside these specific biodiversity hot spots, conservationists should prioritise the five areas of wilderness with the greatest biodiversity. These are Amazonia, the Congo forests of central Africa, New Guinea, the Miombo-Mopane woodlands of southern Africa, and the North American desert. They make up 6.1 per cent of Earth鈥檚 land area, but contain 17 per cent of all plant species and 8 per cent of all vertebrate species.
Critics worry that the wilderness protection vision is politically naive, however. Peter Raven, a botanist and director of the Missouri Botanical Garden in St Louis, says the wilderness survey does not take into account how conservation efforts work in the real world: 鈥淎 lot of these discussions are played out as though somebody is sitting there with billions of dollars they are going to dole out.鈥� He believes the only realistic way to conserve wild habitats is to reduce poverty in the developing world and make it possible for countries to protect their own environments.