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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Rounding Out Rainforest Preserves
4 May 1998 7:30 pm
Cutting corners is a bad idea if you want to help rainforests grow. That's because square tropical forest fragments aren't hospitable to shade-loving seedlings, according to a report in the May issue of Conservation Biology. The finding could help scientists design more effective--and perhaps rounder--rainforest reserves.
Over the last century, logging and farming has turned huge swathes of the Amazon rainforest into a ragged patchwork of disconnected stands. The potential of these leftover patches to shelter rainforest plants and animals is largely unknown. To find out, the Smithsonian Institution and Brazil's National Institute for Research in the Amazon have for two decades led an effort to monitor 11 rainforest patches--from 2.5 to 250 hectares in size--scattered throughout cattle pastures 70 kilometers north of Manaus, Brazil.
As one part of the project, Julieta Benitez-Malvido of the National Autonomous University in Mexico City examined how the square shape of the rainforest fragments influenced the reproduction of shade-loving trees. Like researchers studying other logged forests, she found evidence of an "edge effect": the density of shade-tolerant seedlings decreased within several hundred meters of the fragment edge, where young trees are more exposed to sun, wind, and competition from invading species.
But she found that the edge effect is amplified in corners. In 250-hectare fragments, for instance, Benitez-Malvido found about 25% fewer seedlings growing in the corners than along other edges, and 40% fewer than in the centers. The study indicates that square fragments may shrink over time, she says, with smaller patches shrinking faster.
The "very interesting findings suggest that edge effects are additive--in corners, two create more problems than one," says William Laurance of the Biological Dynamics of Tropical Rainforest Fragments Project in Manaus. To avoid the problem, he says, reserve designers might want to consider planting trees to "round out those edges."