Global warming could make 30pct of land-bird species extinct by 2100

December 7th, 2007 - 4:15 pm ICT by admin  

Washington, Dec 7 (ANI): With habitats fast shrinking due to global warming, a new study warns that climate change will accelerate the rate of extinction among birds and animals.

The finding is based on a study, led by Cagan Sekercioglu, a senior research scientist at Stanford, which reported that by 2100, climate change could cause up to 30 percent of land-bird species to become extinct worldwide.

Land birds constitute the vast majority of all bird species.

”Of the land-bird species predicted to go extinct, 79 percent of them are not currently considered threatened with extinction, but many will be if we cannot stop climate change,” said Sekercioglu.

In the study the researchers modelled changes to the elevational limits of the ranges of more than 8,400 species of land birds using 60 scenarios.

The scenarios consisted of various combinations of surface warming projections from the 2007 IPCC report, habitat loss estimates from the 2005 Millennium Ecosystem Assessment (an evaluation of the planet’s ecosystems by 1,360 experts around the world), and several possibilities of shifts in elevational range limits.

The worst-case scenario of 6.4 degrees Celsius surface warming combined with extensive habitat loss produced the estimate of 30 percent of land bird species going extinct by 2100. Increasing habitat loss exacerbates the effects of climate change because organisms seeking more suitable conditions will be less likely to find intact habitats. Even with an intermediate 2.8 C warming, 400 to 550 land-bird extinctions are expected.

”Vegetational shift is the key issue here. Birds will follow the shift in habitat, Sekercioglu said.

Once the summit of a mountain becomes too hot for a species or its preferred vegetation type, the habitable area is reduced to nothing.

”It’s like an escalator to extinction. As a species is forced upwards and its elevational range narrows, the species moves closer to extinction,” Sekercioglu said.

The study also has shown that sedentary birds, which comprise over 80 percent of all bird species, are much more likely to go extinct from climate change than are migratory birds.

”To effectively monitor the rate of change as warming progresses, especially in the species-rich tropics, we need a lot more data on birds’ distributions and on the speed and extent of birds’ elevational shifts in response to climate change,” Sekercioglu said.

The finding will be published online in Conservation Biology. (ANI)

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