Friday, June 29, 2007

Untouched by man?

Wilderness almost non-existent on planet Earth: study

Humans have domesticated the planet to such a degree that few untouched spots remain, researchers report in a review article published in the journal Science.

Earth is so tamed that conservationism should shift focus from protecting nature from humans to better understanding and managing a domesticated world, the authors said.

"There is no such thing as nature untainted by people," writes Peter Kareiva, chief scientist at the Nature Conservancy, a US-based non-profit group. "Facing this reality should change the scientific focus of environmental science."

As of 1995, only 17 percent of the world's land area remained truly wild -- with no human populations, crops, road access or night-time light detectable by satellite, the authors reported.

Half of the world's surface area is used for crops or grazing; more than half of all forests have been lost to land conversion; the largest land mammals on several continents have been eliminated; shipping lanes crisscross the oceans, according to the paper.

In Europe, 22,000 kilometers of coastline are paved.

Due to extensive damming, nearly six times as much water is held in artificial storage worldwide as is free-flowing, according to the article.

Beyond the obvious signs of human influence, other, more subtle changes are evident everywhere, Kareiva said.

Natural selection has been supplanted by human selection, meaning that certain species -- such as companion pets -- thrive, while others -- such as river trout -- have been altered specifically for human consumption, often to their detriment.

In the African nation of Namibia, overfishing has allowed large jellyfish to bloom. Prior to 1970, fishermen rarely snared large jellyfish in the Benguela ecosystem off the northern coast of Namibia.

Today, three times more jellyfish are caught than commercial fish in this region, according to the paper.

Altering ecosystems leaves them vulnerable to disturbances and less resilient, Kareiva said.

Carving out parkland hasn't worked either, the authors argue.

Protecting nature through national and state parks has only domesticated these regions. The Nature Conservancy's leading mission is protecting private lands.

The Fuji-Hakone-Izu Park in Japan, among the world's most popular parks, for instance, has more than 100 million visitors a year and includes spas, hotels, golf courses and trams.

Heavy human traffic in the worlds' protected areas has changed them forever, introducing non-native species, air pollution and trash, according to the article.

"In the modern world, wilderness is more commonly a management and regulatory designation than truly a system without a human imprint," Kareiva wrote. This trend will only accelerate with human population growth, he said.

In light of this, conservationists need to look more closely at trade-offs among ecosystem services, such as increased food production leading to overuse of antibiotics in animals, "so that nature and people simultaneously thrive," the authors concluded.

Original article posted here.

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