Scientists have long known that habitat fragmentation poses a threat to native species. It can lead to stress on the surviving animals, and weakened genetic fitness due to their smaller breeding populations.
But no one knew just how quickly forest fragmentation could eliminate species. Thanks to a study recently published in Science, we now have an idea – and the results are alarming.
For two decades, biologists have studied fragmented wilderness in Thailand, where in the late 1980s the government flooded a river valley to create a reservoir. As a result, 150 hilltops became isolated islands.
In the early nineties, scientists inventoried mammals on 12 of the islands and found seven different species. In 2012, they repeated the process. This time, none of the original seven species were found. Worse, what they did find was the Malayan field rat, an invasive species that was not present when the islands were formed but now seems to abound.
These findings suggest that habitat fragmentation may lead to the extinction of species in a short period of time. And they echo previous findings on birds in Amazon forest fragments.
“What we find is just the effect that you might expect,” says Stuart Primm, a professor at Duke University. “That small populations go extinct and they go extinct very rapidly. So that species that might survive in continuous forest will quickly disappear from a small fragment, probably because there’s not enough individuals to form a viable breeding population.”
These studies underscore the urgent need to preserve intact forests while we still have the time.
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Web Extra
Full interview with Stuart Primm, a professor at Duke University and the president of Saving Species
[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2014/01/Primm_full_web.mp3|titles=Primm_full_web].
Web Links
Saving Species
In Fragmented Forests, Rapid Mammal Extinctions
Ecological Armageddon: Forest Fragmentation Causing Rapid Extinction Of Mammal Species
Near-Complete Extinction of Native Small Mammal Fauna 25 Years After Forest Fragmentation
http://www.sciencemag.org/content/341/6153/1508
Photo, taken on June 21, 2011, courtesy of NRCS Oregon via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.