Many bird species face extinction

2004-12-14 14:32

Washinton - About 10% of all bird species face extinction by the end of the century and 15% more are on the brink, according to researchers who say such extinctions would have a widespread impact on the environment, agriculture and human society.

"Important ecosystem processes, particularly decomposition, pollination and seed dispersal, will likely decline as a result" of the loss of bird species, said Cagan H Sekercioglu of the Stanford University Centre for Conservation Biology.

The forecast of Sekercioglu and colleagues, published online Monday by Proceedings of the National Academy of Science, comes a month after the World Conservation Union reported a continuing loss of species, including an estimate that 12% of birds are threatened with extinction.

The Stanford estimate was based on a year of study and a computer calculation of three possible scenarios.

The result was a forecast that between 6 and 14 percent of all bird species will be extinct by 2100 and 700 to 2 500 species will be critically endangered or extinct in the wild.

"Given the momentum of climate change, widespread habitat loss and increasing numbers of invasive species, avian declines and extinctions are predicted to continue unabated in the near future," Sekercioglu said.

Such losses, the team said, could have a significant impact in many aspects of society.

For example birds pollinate many plant species and carry the seeds of others to new locations.

"Declines in pollination and seed dispersal as a result of bird extinctions may lead to extinctions of dependent plant species," they concluded. This is particularly important in Australia, New Zealand and oceanic areas where pollination and seed dispersal by birds is more common, they said.

Another problem could occur with the loss of scavenging birds that help dispose of the bodies of large animals by consuming the flesh and leading other scavengers to the bodies, a process that helps limit the spread of disease from decomposing carcasses.

As an example, they noted that a sharp drop in the vulture population in India in the 1990s was followed by a jump in the population of rats and wild dogs, some of which spread rabies.

Birds also eat millions of insects, and a decline in birds could lead to a dangerous increase in damaging pests, the researchers said.

The research was funded by Dr Walter Loewenstern and the Koret and Winslow foundations.

- SAPA