sábado, 29 de maio de 2010

Wetland aliens cause bird extinction


BirdLife International has announced, in the 2010 IUCN Red List update for birds, the extinction of Alaotra Grebe Tachybaptus rufolavatus. Restricted to a tiny area of east Madagascar, this species declined rapidly after carnivorous fish were introduced to the lakes in which it lived. This, along with the use of nylon gill-nets by fisherman which caught and drowned birds, has driven this species into the abyss.

"No hope now remains for this species. It is another example of how human actions can have unforeseen consequences", said Dr Leon Bennun, BirdLife International's Director of Science, Policy and Information. "Invasive alien species have caused extinctions around the globe and remain one of the major threats to birds and other biodiversity."

Another wetland species suffering from the impacts of introduced aliens is Zapata Rail Cyanolimnas cerverai from Cuba. It has been uplisted to Critically Endangered and is under threat from introduced mongooses and exotic catfish. An extremely secretive marsh-dwelling species, the only nest ever found of this species was described by James Bond, a Caribbean ornithologist and the source for Ian Fleming's famous spy's name.

And it's not just aliens. Wetlands the world over, and the species found in them, are under increasing pressures.

In Asia and Australia, numbers of once common wader species such as Great Knot Calidris tenuirostris and Far Eastern Curlew Numenius madagascariensis are dropping rapidly as a result of drainage and pollution of coastal wetlands. The destruction of inter-tidal mudflats at Saemangeum in South Korea, an important migratory stop-over site, correlated to a 20% decline in the world population of Great Knot. Huge flocks of these birds once visited northern Australia, but annual monitoring by scientists have found corresponding declines in numbers.

"Wetlands are fragile environments, easily disturbed or polluted, but essential not only for birds and other biodiversity but also for millions of people around the world as a source of water and food", said Dr Stuart Butchart, BirdLife's Global Research and Indicators Coordinator.

Fonte: http://www.birdlife.org/news/news/2010/05/red-list-for-birds-2010.html

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