26 March 2013

Human Colonization in the Pacific Resulted in the Extinction of 1300 Bird Species


The takahē is a large flightless rail (a land-based relative of our familiar coot and moorhen) from New Zealand.
Researchers found that human colonization in 41 tropical islands in the Pacific such as Hawaii and Fiji has resulted in the extinction of around 1,300 species of birds.

Human colonization has a major impact on nature. Natural habitats of birds are disturbed, extended hunting of these species and also deforestation to reclaim land are some of the factors that affect the population of birds.

The most famous of extinct species of birds is the dodo bird. It is a flightless bird found in the island of Mauritius, east of Madagascar in the Indian Ocean. It is the first species that has gone extinct that is directly attributed to humans. Because of the lack of predators of the dodo in Mauritius, the dodo is said to be easily hunted.

Aside from the dodo, countless species has gone extinct due to the expansion of human civilization. On December 28, 1973, US President Richard Nixon signed into law the Endangered Species Act. It ensures that endangered species are given protection and conservation. The law also covers and protects the ecosystems that these species depend on.

Far More Bird Species Gone Extinct Than Previously Speculated

Research carried out by the Zoological Society of London (ZSL) and collaborators reveals that the last region on earth to be colonised by humans was home to more than 1,000 species of birds that went extinct soon after people reached their island homes.

The paper was published today (25th) in the journal Proceedings of the National Academy of Sciences USA.

Almost 4,000 years ago, tropical Pacific Islands were an untouched paradise, but the arrival of the first people in places like Hawaii and Fiji caused irreversible damage to these natural havens, due to overhunting and deforestation. As a result, birds disappeared. But understanding the scale and extent of these extinctions has been hampered by uncertainties in the fossil record.

Professor Tim Blackburn, Director of ZSL's Institute of Zoology says: "We studied fossils from 41 tropical Pacific islands and using new techniques we were able to gauge how many extra species of bird disappeared without leaving any trace."

Video: Australian birds fast becoming extinct

They found that 160 species of non-passerine land birds (non-perching birds which generally have feet designed for specific functions, for example webbed for swimming) went extinct without a trace after the first humans arrived on these islands alone.

"If we take into account all the other islands in the tropical Pacific, as well as seabirds and songbirds, the total extinction toll is likely to have been around 1,300 bird species," Professor Blackburn added.

Species lost include several species of moa-nalos, large flightless waterfowl from Hawai'i, and the New Caledonian Sylviornis, a relative of the game birds (pheasants, grouse, etc) but which weighed in at around 30kg, three times as heavy as a swan.

Certain islands and bird species were particularly vulnerable to hunting and habitat destruction. Small, dry islands lost more species because they were more easily deforested and had fewer places for birds to hide from hunters. Flightless birds were over 30 times more likely to become extinct that those that could fly.

Bird extinctions in the tropical Pacific did not stop with these losses. Forty more species disappeared after Europeans arrived, and many more species are still threatened with extinction today.

RELATED LINKS

Zoological Society of London
Proceedings of the National Academy of Sciences
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