Splinters of the Amazon

Decades after Thomas Lovejoy isolated fragments of the Brazilian rainforest in a grand experiment, researchers are building on his legacy around the world.

Published online on April 17, 2013, in Nature.

Ecologist Thomas Lovejoy tucks his trousers into his socks with a casual warning about chiggers and then hikes off into the Amazon jungle. Shaded by a tall canopy and dense with ferns and underbrush, the old-growth forest looks healthy, but Lovejoy knows better. Three decades ago, the surrounding forest was mowed down and torched as part of a research project, and the effects have spread like a cancer deep into the uncut area. Large trees have perished. The spider monkeys have moved out, as have the army-ant colonies, and many of the birds that depend on them.

Lovejoy and his team have been studying this 10-hectare fragment of forest since the late 1970s as part of the largest and longest-running experiment in tropical ecology. In collaboration with ranchers, they cleared the trees around this and ten other plots of varying size to create islands of intact forest. The researchers have been monitoring the plots ever since, documenting how deforestation harms the adjacent untouched forest as specialist plants and animals gradually give way to generalists and pioneer species that prefer disturbed habitat. “We are chronicling the simplification of these forests,” says Lovejoy, a professor at George Mason University in Fairfax, Virginia.

Covering roughly 1,000 square kilometres in an area north of Manaus in the central Amazon, the experiment was set up to test fundamental theories about the viability of small, disconnected ecosystems. By documenting pervasive changes in the forest fragments, Lovejoy and his co-workers provided the first hard data that conservationists needed to promote the preservation of extensive areas of intact forest. “It’s the most important ecological experiment ever done,” says Stuart Pimm, a conservation ecologist at Duke University in Durham, North Carolina, who has collaborated on the project. “We knew that small and isolated was bad, but we needed to know how bad.”

The researchers are now exploring the long-term effects of habitat fragmentation, but the ecological record there is ironically threatened by forest that is taking over abandoned pastures. Although Lovejoy has struggled to maintain financing for long-term monitoring, the US National Science Foundation is breathing new life into the project by funding the team to isolate some of the plots anew.

The experiment has also helped to train and inspire a generation of ‘fragmentologists’, who are working around the world to understand the cascade of ecological impacts that follow human development. Most notably, in early April, an international team started chopping down trees in Borneo as part of an nearly £6-million (US$9-million) experiment that replicates and extends the Brazilian one.

“The Amazon experiment changed the game,” says Rob Ewers, principal investigator on the Borneo project at Imperial College London. “I like to think of our project as the next step.”

The ambassador

“Welcome to Camp 41,” says Lovejoy, beaming at a group of guests he invited to tour the experiment — and do a little bird-watching — over New Year’s Eve, an annual tradition. Fit at 71, he has a slight paunch, a crop of thinning hair and pale skin that is a touch reddish from the heat and the hike to his forest base. Lovejoy offers a quick tour of the open-air shelters that house hammocks and dining facilities as well as the bathrooms, showers and a makeshift pool down a trail by the stream. Over the years, he has entertained a long list of high-profile guests here, ranging from Al Gore (when he was a senator) to actor Tom Cruise and high-ranking Brazilian officials.

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