The main driver of wildlife extinction is not climate change but humanity's rapacious harvesting of species for food and trophies, along with our ever-expanding agricultural footprint, said researchers pleading for a reset of conservation priorities.

In an analysis of nearly 9,000 "threatened" or "near-threatened" species, the scientists found that three-quarters are being over-exploited for commerce, recreation or subsistence.

Demand for meat and body parts, for example, have driven the Western gorilla and Chinese pangolin to near extinction, and pushed the Sumatran rhinoceros -- prized in China for bogus medicines made from its horn -- over the edge. 

And more than half of the 8,688 species of animals and plants evaluated are suffering due to the conversion of their natural habitats into industrial farms and plantations, mainly to raise livestock and grow commodity crops for fuel or food.

By comparison, only 19 percent of these species are currently affected by climate change, they reported in a study published in the peer-reviewed journal Nature.

Conservation budgets, the researchers argued, must reflect this reality.

"Addressing the old foes of overharvesting and agricultural activities are key to turning around the biodiversity extinction crisis," said lead author Sean Maxwell, a professor at the University of Queensland in Australia.

These threats, rather than climate change, "must be at the forefront of the conservation agenda," he said in a statement.

A group of 43 top conservation experts, meanwhile, issued a public appeal recently to save the world's dwindling terrestrial megafauna, from big cats to elephants to giant apes. 

"They are vanishing just as science is discovering their essential ecological roles," they wrote in BioSciences. Unless funding to save them increases at least tenfold, they "may not survive to the 22nd century," they added. 

The provocative appeal in Nature -- which elicited sharp reactions -- comes a month before a crucial meeting of the International Union for Conservation of Nature (IUCN), a policy-oriented umbrella grouping of governments, industry and NGOs that meets every three or four years.

The IUCN also manages the gold-standard Red List of endangered species, tracking and cataloguing the health of Earth's flora and fauna. 

- Mass extinction event -

Climate change has overshadowed more traditional conservation priorities over the last decade, siphoning limited resources -- and cash -- away from more urgent needs, the authors argued.

In December, 195 nations inked the Paris Agreement, the first global pact to curb greenhouse gas emissions and help poor countries cope with global warming impacts such as rising seas, drought and superstorms.

The agreement -- which could be ratified as early as this year -- calls for the mobilisation of hundreds of billions of dollars in the coming decades.

The Nature analysis acknowledges global warming could become an increasingly dominant menace for biodiversity in the coming decades.

"But, overwhelmingly, the most immediate threat comes from agriculture and over-exploitation," said co-author James Watson, a biodiversity expert at the Wildlife Conservation Society. 

"Unless we tackle these problems now, many species may disappear by the time the full impacts of climate change really kicks."

Earth, he pointed out, has now entered a "mass extinction event" in which species are disappearing 1,000 to 10,000 times more quickly than a century or two ago.

There have only been six such wipeouts in the last half-billion years, some of them claiming up to 95 percent of all life forms.

"It is hard to exaggerate just how dramatic the threat to Earth's species really is," Watson said.

Other conservationists were critical of both the Nature analysis, and the accompanying appeal.

"There is no need to see tradeoffs among different conservation priorities -- we need them all," Peter MacIntyre, an expert on the ecology of fresh-water systems at the University of Wisconsin, told AFP.

MacIntyre illustrated that very point in a study, published this week, that fingered climate change, as well as over-fishing and pollution, for the depletion since 1950 of fish stocks in central Africa's Lake Tanganyika, a vital source of protein for millions.

"What good is it protecting a habitat that becomes oxygen-deprived or too hot for its current species due to climate warming, or where lake levels drop due to changes in precipitation patterns?", he asked.

It does not, in other words, makes sense to look at different problems in isolation.

Christopher Wolf, an expert on large carnivores at Oregon State University, agrees with the Nature analysis, noting that hunting and habitat loss are -- at least for big cats and wolves -- much greater dangers in the near term.

But all the pressures closing in on Earth's biodiversity do have one thing in common, he added: "all threats faced by species are caused by man."

Source: AFP