Study Predicts a Bleak Future for Many Birds
By Jim Robbins
A just-published analysis of some 200 separate studies of the impact of climate change on birds is grim.
There are about 10,000 bird species globally and most of them live on land. Based on the middle range of the Intergovernmental Panel on Climate Change’s projection of warming—3.5 degrees Celsius or 6.3 degrees Fahrenheit by the year 2100— 534 to 800 tropical land bird species could become extinct, out of a total of 7,565 species. Worldwide, of all of the 8,500 or so land bird species, as many as 600 to 900 could disappear.
And for each degree of climate warming above that, the experts say, another 100 to 500 birds might go extinct.
“It’s yet another wake-up call,” said Cagan H. Sekercioglu, an assistant professor of biology at the University of Utah and one of the authors of the study, which was published online in Biological Conservation. “Birds are sentinels of what’s happening to the planet, the canary in the coal mine,” he said. “If this is happening to birds, and they can migrate, then for other organisms, it’s going to be worse.”
The other authors of the study, “The Effects of Climate Change on Tropical Birds” are Richard Primack, a biologist at Boston University, and Janice Wormworth, an ecological consultant in Australia.
The loss of birds could be mitigated somewhat, the scientists write, by conducting more research into the subject, by restoring degraded habitat and by protecting more land.
The wide range of numbers on possible extinctions is because of the wide range of human decisions that have yet to be made that could affect outcomes. Will temperatures be mitigated by reductions in carbon output? How will rainfall patterns shift? How much more habitat loss or habitat protection will there be? What diseases will emerge or become more virulent?
Those birds most at risk include tropical mountain-dwelling birds, which to survive are forced higher in elevation to stay in their habitat. But eventually there is no habitat because vegetation moves higher in response to climate and then disappears. Ducks, geese and waders may lose their habitat as sea levels rise and reaches shoreline without habitat because of highways, homes and other developments by people.
Birds will be missed. Beyond their role as a sentinel, an indicator of what is happening in the environment, birds are crucial for other reasons, Dr. Sekercioglu said. Farmers, hunter-gatherers, nomadic herders and others, especially in less developed countries, depend on a healthy environment, and birds are important for ecosystem services like seed dispersal and insect control.
One study in Jamaica found that several birds, including the red-billed streamer tail and the Jamaican mango, both hummingbirds, ate more than half of the most damaging pests that live on coffee plants, worth about 12 percent of the total value of the crop.
Copyright © Copyright © 2012 The New York Times.
This article originally appeared here.
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