Nature - At Least Half Of All Terrestrial Bird Species Face Extinction Threat In Study's Worst-Case

[hatrack]

With wild eyes and a dishevelled hairdo, Africa's white-crested hornbill (Tropicranus albocristatus) has a distinctly disgruntled look. Whatever is doing the disgruntling, though, has so far not been seen as life threatening. The bird is numerous and secure enough to have been declared of "least concern" by the conservation group BirdLife International. But that may be about to change. In a new study, ecologist Walter Jetz of the University of California, San Diego, and his colleagues have predicted the fate of 8,750 non-marine bird species in a world in which continuing climate change and new patterns of land use by humans transform Earth's landscape.

Over the next century, they found, the white-crested hornbill and almost 1,000 other species may lose more than half of their favourite feeding grounds, pushing them well beyond the "least concern" stage. More than 50 of those species could potentially be pushed to extinction. That's higher than the current predictions made by the IUCN, the World Conservation Union;of the 80 species facing extinction at the upper end of Jetz' estimate, only 41 are currently listed as "threatened" by the IUCN.

The results, reported this week in PloS Biology1, add to the deluge of reports predicting the impact of climate change on wildlife. But this study is unique in its consideration of both climate change and changing human land use. While everyone leaps onto the climate-change bandwagon, Jetz hopes the report will serve as a reminder that the age-old problems of deforestation and land conversion are still critical.

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The findings are based on models created by the Millennium Ecosystem Assessment (MEA) project, a United Nations-commissioned report on upcoming ecological changes that included scenarios for land-use change. Jetz and his colleagues trawled through bird guides and handbooks to find range maps for 8,750 species of birds, which was as many as they could get. They then overlaid these ranges on the MEA's vegetation maps, and measured the change in vegetation over each bird's range. Those losses were dramatic. In the MEA's relatively benign 'Adapting Mosaic' scenario, in which environmental problems are handled proactively, about a quarter of the Earth's land was transformed by 2100: 16% due to climate change and 9% due to land-use changes. In another scenario, one in which little proactive environmental planning took place, habitat loss in tropical regions was approximately twice as high. Overall, Jetz projected the number of threatened bird species to increase by 19-30% by 2050, and 29-52% by 2100.

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http://www.nature.com/news/2007/070604/full/070604-2.html

[JohnF]

1. And it's not just birds

In fact, E.O Wilson and others are concerned about a loss of 50% of all species by the end of the century:

http://growthmadness.org/2007/02/22/the-specter-of-mass-extinction/

Current estimates have species loss happening at 100 to 1000 times normal background rates.

"While everyone leaps onto the climate-change bandwagon, Jetz hopes the report will serve as a reminder that the age-old problems of deforestation and land conversion are still critical."

That's a key quote, and we can go one more step: People need to realize it's actually a whole array of environmental issues including the collapse of fisheries, the global spread of chemical toxins, desertification from overgrazing, etc., all of which are linked to varying degrees, btw, with corporate economic growth and population growth. Add in, as well, resource depletion (oil, ground water...). There are a number of issues, any one of which may have profound impact. Together, well, people need to realize there's a global ecological crisis.

[NMDemDist2]

2. welcome to DU JohnF

and the scariest forum around here too

:hi:

[JohnF]

3. Thanks!

Hey thanks, AZ/NM. :thumbsup:

We must face our fears. :yoiks: