Up a Tree

We’re killing off the animals that make tropical forests great carbon sinks.

December 22, 2015
A properly-functioning forest ecosystem, with large animals

Illustration courtesy of Mauro Galetti

Tropical forests are called the “lungs of the earth” for good reason—these ecosystems store about 40 percent of the world’s carbon. So deforestation is obviously bad news for the climate, but a new study identifies a lesser-known threat to these massive carbon sinks: hunters.

See, the big trees that suck up the most CO2 depend on big animals to disperse their seeds for them. But hunting, the illegal wildlife trade, and habitat loss increasingly threaten those helpful fruit eaters. Without as many tapirs and toucans around, as the figure below shows, a less carbon-hungry forest emerges. Speaking for the trees is important, but its not the whole picture.

A forest ecosystem without large animals

Illustration courtesy of Mauro Galetti

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