Herd of elephants crossing a river in Kenya. Photo by: Rob Roy.
Scientists have long known that African elephants (Loxodonta africana) are talented tree-topplers, able to take down even large trees in order to gobble out-of-reach leaves. However the extent of his behavior across a large area has been difficult to quantify. But a new study in Ecology Letters has used a bird’s-eye view—with 3-D—of Kruger National Park in South Africa to determine the impact of elephants on trees.
“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,” says lead author Greg Asner of Carnegie’s Department of Global Ecology in a press release.
Asner and his team employed their Carnegie Airbone Observatory (CAO), a airplane mounted with a Light Detection and Ranging (LiDAR) model, creating incredible 3-D images of vegetation using lasers. Monitoring over 50,000 trees, the researchers found that elephants were responsible for about 20 percent of downed trees between 5 and 8 meters tall (16-30 feet).
“Our maps show that elephants clearly toppled medium-sized trees, creating an ‘elephant trap’ for the vegetation,” Asner explains. “These elephant-driven tree losses have a ripple effect across the ecosystem, including how much carbon is sequestered from the atmosphere.”
Elephant tree-toppling is of course a natural impact that has been going occuring for millions of year. However greater insight into the pachyderms’ behavior will help the government manage the region.
“Knowing where increasing elephant impacts occur in sensitive landscapes allows park managers to take appropriate and focused action,” noted Danie Peinaar, South African National Parks’ head of science.
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