Tag Archives: cao

Gold Mining Ravages Perú

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Washington, DC—For the first time, researchers have been able to map the true extent of gold mining in the biologically diverse region of Madre De Dios in the Peruvian Amazon. The team combined field surveys with airborne mapping and high-resolution satellite monitoring to show that the geographic extent of mining has increased 400% from 1999 to 2012 and that the average annual rate of forest loss has tripled since the Great Recession of 2008. Until this study, thousands of small, clandestine mines that have boomed since the economic crisis have gone unmonitored. The research is published in the online early edition of the Proceedings of the National Academy of Sciences the week of October 28, 2013.

The team, led by Carnegie’s Greg Asner in close collaboration with officials from the Peruvian Ministry of Environment, used the Carnegie Landsat Analysis System-lite (CLASlite) to detect and map both large and small mining operations. CLASlite differs from other satellite mapping methods. It uses algorithms to detect changes to the forest in areas as small as 10 square meters, about 100 square feet, allowing scientists to find small-scale disturbances that cannot be detected by traditional satellite methods. (more…)

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Airborne Technology Helps Manage Elephants

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Washington, D.C. – For years, scientists have debated how big a role elephants play in toppling trees in South African savannas. Tree loss is a natural process, but it is increasing in some regions, with cascading effects on the habitat for many other species. Using high resolution 3-D mapping, Carnegie scientists have for the first time quantitatively determined tree losses across savannas of Kruger National Park. They found that elephants are the primary agents—their browsing habits knock trees over at a rate averaging 6 times higher than in areas inaccessible to them. The research also found that elephants prefer toppling trees in the 16-to-30 foot (5-8 m) range, with annual losses of up to 20% in these height classes. The findings, published in Ecology Letters, bolster our understanding of elephant conservation needs and their impacts, and the results could help to improve savanna management practices.

“Previous field studies gave us important clues that elephants are a key driver of tree losses, but our airborne 3-D mapping approach was the only way to fully understand the impacts of elephants across a wide range of environmental conditions found in savannas,” commented lead author Greg Asner of Carnegie’s Department of Global Ecology. “Our maps show that elephants clearly toppled medium-sized trees, creating an “elephant trap” for the vegetation. These elephant-driven tree losses have a ripple effect across the ecosystem, including how much carbon is sequestered from the atmosphere.” (more…)

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