End of Alaotra Grebe Is Further Evidence of Sixth Great Extinction
Species are vanishing quicker than at any point in the last 65 million years
One more step in what scientists are increasingly
referring to as the Sixth Great Extinction is announced today: the
disappearance of yet another bird species. The vanishing of the Alaotra
grebe of Madagascar is formally notified this morning by the global
conservation partnership BirdLife International - and it marks a small
but ominous step in the biological process which seems likely to
dominate the 21st century.
Researchers now recognise five earlier
cataclysmic events in the earth's prehistory when most species on the
planet died out, the last being the Cretaceous-Tertiary extinction event
of 65 million years ago, which may have been caused by a giant
meteorite striking the earth, and which saw the disappearance of the
But the rate at which species are
now disappearing makes many biologists consider we are living in a sixth
major extinction comparable in scale to the others - except that this
one has been caused by humans. In essence, we are driving plants and
animals over the abyss faster than new species can evolve.
Birds species alone now seem to be disappearing at
the rate of about one per decade, and the extinction of the Alaotra
grebe is announced in the BirdLife-produced update to the Red List of
threatened bird species maintained by the International Union for the
Conservation of Nature (IUCN).
A handsome bird
not dissimilar to our own little grebe or dabchick, it inhabited a tiny
area in the east of Madagascar, and declined after carnivorous fish were
introduced into the freshwater lakes where it lived, and fishermen
began using nylon gillnets which caught and drowned the birds. Its
demise brings the total number of bird species thought to have become
extinct since 1600 to 132.
Moreover, the new
edition of the Red List shows that 1,240 species of birds (around an
eighth of the 10,027 total) are themselves now in danger of
disappearance - which is a rise of 21 from last year's assessment.
"The confirmation of the extinction of yet another
bird species is further evidence that we losing the fight to protect the
world's wildlife," said Dr Tim Stowe, international director of the
Royal Society for the Protection of Birds. "Although there are some key
successes, overall the trend is downward, bringing more species year on
year to the brink of extinction and beyond."
only in Madagascar, and chiefly from Lake Alaotra, Tachybaptus
rufolavatus was probably incapable of prolonged flight, so may never
have occurred very far from the lake itself. None have been seen since
1999 and the most recent surveys in the region failed to find any
"No hope now remains for this species,"
said Dr Leon Bennun, BirdLife's director of science, policy and
information, announcing the change in its classification from critically
endangered to extinct. "It is another example of how human actions can
have unforeseen consequences. Invasive alien species have caused
extinctions around the globe and remain one of the major threats to
birds and other biodiversity."
species suffering from the impacts of introduced aliens is the Zapata
rail from Cuba, whose status has now been moved up 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, an American
ornithologist and the source for the name of Ian Fleming's famous spy.
(The real James Bond was the author of Birds of The
West Indies and Fleming, himself a keen birdwatcher, had a copy of the
book in his Jamaican hideaway, Goldeneye, where he wrote the Bond
In fact, BirdLife says, wetland birds
everywhere are under increasing pressure. In Asia and Australia, numbers
of once-common wader species such as the great knot and Far Eastern
curlew 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 per cent decline in the world population of great knot.
There is, however, a little good news in the new Red
List. The Azores bullfinch, has been downlisted from Critically
Endangered to Endangered as a result of conservation work to restore
natural vegetation on its island home of Sao Miguel; the Chatham
albatross from New Zealand has also been downlisted from Critically
Endangered to Vulnerable following an improvement in the bird's status,
and the Laysan albatross is removed from the list following a similar
Earth's Five Great Extinctions
65 million years ago (mya)
Cretaceous-Tertiary (K-T extinction). Did for the dinosaurs. May have
been caused by a meteorite hitting what is now Yucatan, Mexico; 75 per
cent of species disappeared.
Triassic-Jurassic extinction. Did away with competition for the
251mya Permian-Triassic (the
worst of all). Known as "The Great Dying." About 96 per cent of marine
species and 70 per cent of land species disappeared.
360-375mya Late Devonian. A prolonged series of
extinctions which may have lasted 20 million years.
440-450mya Ordovidician-Silurian. Two linked
events which are considered together to have been the second worst
extinction in the list.