For every Kirtland's Warbler and California Condor — species whose chances at avoiding extinction have improved thanks to conservation efforts — at least six more species have slid closer to extinction in the last two decades, according to new research.
And that's just looking at the world's birds. Mammals and amphibians are moving closer to extinction at even faster rates and have fewer success stories.
An international team of more than 170 scientists analyzed data for more than 25,000 vertebrate species categorized on the International Union for the Conservation of Nature Red List. They report in the journal Science that one-fifth of species are classified as threatened, and this figure is increasing. On average, 52 species of mammals, birds, and amphibians move one category closer to extinction each year.
The researchers identify four drivers of biodiversity loss: agricultural expansion, logging, over-exploitation, and invasive alien species.
"The backbone of biodiversity is being eroded," says ecologist and author Edward O. Wilson of Harvard University. "One small step up the Red List is one giant leap forward towards extinction. This is just a small window on the global losses currently taking place."
The news is not all gloom and doom, however. The authors provide evidence that conservation efforts have worked. In fact, the scientists estimate that overall declines would have been at least 16 percent worse without any conservation actions. Efforts that dealt with invasive species have been more effective than those attempting to address habitat loss or hunting, the researchers report.
Their paper identifies 269 bird species that have moved at least one category up or down on the Red List since 1988. Four birds — Malaysian Whistling-thrush, Woodford's Rail, Plain Pigeon, and Lesser Florican — showed improvements without conservation action, 35 improved due to conservation efforts, and the remaining 230 have moved closer to extinction.
Most of the improvements have come on small islands, where threats to birds are more manageable. "A few decades ago, small islands were the main challenges" for reducing extinctions, says Ana Rodrigues of the Center for Evolutionary and Functional Ecology in Montpellier, France. "And now we see them as relatively easy. They weren't easy. A lot of work went into conserving those species. But in a sense they are now relatively easy because now the wave of extinction has moved from islands to the continents."
Stuart Butchart, global research coordinator at BirdLife International, points to two island nations in the Indian Ocean — Mauritius and Seychelles — as "shining beacons of conservation success."
Six birds from Mauritius and two from the Seychelles have been downgraded on the Red List, giving the two nations 23 percent of the world's recently downlisted birds. (See the full list below.)
"They have implemented actions over the last couple of decades tackling the conservation of a suite of species in both of these island nations that were very close to extinction," says Butchart. "They are inspiring examples of how a country can reverse the fortunes of biodiversity within its borders."
The United States, on the other hand, has a long way to go, despite the success of the Kirtland's Warbler and California Condor. Butchart says that on a global scale, he'd like to see the U.S. "show leadership in the field of biodiversity conservation," and he called out the U.S. for what he called "the appalling extinction hotspot of Hawaii."
"There are a very large number of species that have recently gone extinct and a suite of species that are teetering on the brink of extinction right in America's backyard," he says.
For biodiversity conservation to reverse the extinction crisis, Butchart says funding must be increased ten-fold "so that every country has the resources to implement" the Convention on Biological Diversity, which is currently being negotiated in Japan.
Downlisted birds
Here are the 35 species whose Red List status has improved in the last 20 years thanks to conservation efforts:
Puna Flamingo Argentina, Bolivia, Chile, and Peru
Albert's Lyrebird Australia
Norfolk Island Parakeet Australia
Western Bristlebird Australia
Lear's Macaw Brazil
Red-billed Curassow Brazil
Red-tailed Amazon Brazil
Chatham Petrel Chatham Islands, New Zealand
Asian Crested Ibis China
Black-faced Spoonbill China, Japan, Korea, and other Asian countries
Abbott's Booby Christmas Island (Australia)
Christmas Hawk-owl Christmas Island (Australia)
Christmas Imperial-pigeon Christmas Island (Australia)
Christmas White-eye Christmas Island (Australia)
Yellow-eared Parrot Colombia and Ecuador
Dalmatian Pelican Eastern Europe, Egypt, and east-central Asia
Marquesan Imperial-pigeon French Polynesia
Mauritius Fody Mauritius
Mauritius Kestrel Mauritius
Mauritius Parakeet Mauritius
Pink Pigeon Mauritius
Rodrigues Fody Mauritius
Rodrigues Warbler Mauritius
Black-vented Shearwater Mexico and U.S.
Cook's Petrel New Zealand
Little Spotted Kiwi New Zealand
Madeira Laurel Pigeon Madeira Island, Portugal
Rarotonga Monarch Rarotonga Island of the Cook Islands in the south Pacific
Barau's Petrel Réunion Island in the Indian Ocean
Seychelles Fody Seychelles
Seychelles Magpie-robin Seychelles
White-tailed Eagle Greenland to Japan; strongholds in Norway and Russia
Polynesian Megapode Tonga
California Condor U.S. and Mexico
Kirtland's Warbler U.S., Canada, and Bahamas
--Matt Mendenhall, Associate Editor
Photo: Kirtland's Warbler by Laura Gooch, Creative Commons 2.0
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