A new study published last week in Current Biology: Catastrophic Declines in Wilderness Areas Undermine Global Environment Targets, by James Watson et al. and reviewed in Science asserts that we’ve destroyed one-tenth of the Earths wilderness in just two decades.
Conservation certainly includes protecting declining wild fauna and flora, however, Watson thinks we’re missing the big picture. Large regions of wilderness are also in need of protection. The study compares the extent of Earth’s wilderness areas in 1993 and 2009, documenting almost a 30% loss in South America and a 10% loss globally.
Similar estimates in the past focused on deforestation, but this new study looks at the disappearance of a broader range of wild landscapes. “This is the first time that anyone has put a number on the loss,” says Tim Newbold, a conservation biologist at University College London whose own work shows that wilderness areas contain the world’s most undisturbed biodiversity. Such unspoiled regions, scientists argue, are also critical for allowing the planet to cope with climate change.
Watson, a conservation bio-geographer with the Wildlife Conservation Society based at the University of Queensland, St. Lucia, in Brisbane, Australia, and his colleagues earlier determined the extent of the “human footprint” on Earth by incorporating maps and data on crop lands, pastures, night lighting, railways, roadways, navigable waterways, population densities, and “built” environments, which includes urban areas and other settlements. For most of these threats to wilderness, they had satellite and other data from the early 1990s and for the late 2000s. All but two of these pressures have increased in that time, Watson and his colleagues reported in a study last month in Nature Communications. (Roadways and waterways haven’t expanded noticeably.)
Wilderness is defined as pristine landscapes mostly free of human disturbances, including roads. Watson’s team adjusted the wilderness detected in satellite images to exclude places experiencing these human pressures to come up with the total area of wilderness. They also excluded Antarctica and similar “rock and ice” habitats, the oceans, and large lakes.
By 2009, about 23% of Earth’s land remained as wilderness—about 30.1 million square kilometers spread mostly across North America, North Asia, North Africa, and Australia—that’s 3.3 million square kilometers less than in 1993, an area about twice the size of Alaska—Watson says. South America lost almost 30% of its wilderness in that time and Africa lost 14%. The losses included the total devastation of several large strips of forest and swamp in the Congo and in New Guinea.
One reason for the trend, Watson and others say, is that governments and conservation organizations often prioritize their protection efforts on habitat that is severely threatened or degraded. But left unguarded, remote land is vulnerable to homesteading farmers and claim-seeking miners.
Work on remote coral reefs drive home why pristine places are important to biodiversity and suggests why other types of wilderness areas need protection. Stéphanie D’agata, now with the Wildlife Conservation Society in Antananarivo, found that even the oldest, best managed marine protected area lacks the variety of organisms “that we find in wilderness areas,” she says. In June, she reported that she can’t find organisms common in remote reefs in marine protected areas close to human influences.
Harvard University biologist Edward O. Wilson is now arguing for the preservation of half Earth’s land (even if it’s not all wilderness) and oceans and Mittermeier and others think that protecting that fraction of forests can be “50% of the climate change solution.”