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So Many Species, So Little Space

Thirty years ago, Dr. Tom Lovejoy, the chairman of National Geographic’s Conservation Trust, set up a unique experiment to monitor biodiversity in Brazil. It’s to be repeated in Borneo, conservation biologist Stuart Pimm reports from Borneo for Nat Geo News Watch.

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Photo of oil palm plantation by Stuart Pimm

By Stuart L. Pimm
Special Contributor to NatGeo News Watch

Borneo, Malaysia–The flight from Kota Kinabalu to Lahad Datu across the northern end of the island of Borneo passes south of Mount Kinabalu–at 4,000 metres (13,400 feet) the tallest mountain in southeast Asia. Above it, and towering above us, is a massive thundercloud, threateningly black with its edges backlit by sunlight.

Such storms bring part of the three meters (120 inches) of rain that makes this tropical forest grow.

But exactly the same conditions make the land below a perfect place for oil palms, a crop that has rapidly become the dominant land use in much of southeast Asia. Princeton University ecologists Lian Pin Koh and David Wilcove showed in a paper in Conservation Letters last year that there are now more then 13 million hectares (52,00 square miles) of oil palm.

As we land in Lahad Datu, the land below us is mostly oil palm.

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Photo of oil palm fruits on the way to market by Stuart Pimm

Like most monocultures–cropland where only one species is planted–these oil palm plantations are home to very few species.

Many conservation biologists view the expansion of oil palm as one of the greatest threats to biodiversity. And Borneo is a country that teems with species of plants and animals. (See Pimm’s related story “An Inordinate Passion for Moths.”

Experiences elsewhere in the world tell us that some forest will remain after clearing for crops and cattle grazing.

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Photo of cattle grazing in a Brazilian clearing by Stuart Pimm

It was the threat posed by cattle-grazing–and the need to understand how many species would remain in small fragments–that led Lovejoy and Brazilian colleagues to create an extraordinary experiment in the middle of the Amazon forest thirty years ago.

It’s known as the BDFFP–the Biological Dynamics of Forest Fragments Project.

Lovejoy holds the Biodiversity Chair at the Heinz Center in Washington D.C. and also chairs National Geographic’s Conservation Trust.

The experiment, north of Manaus, used the forest clearing for cattle ranching to establish a set of plots–of one hectare (roughly 100 by 100 yards), 10 hectares, and 100 hectares. Some control plots of the same size were marked out in forest that would remain intact.

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Photo of forest fragments in Brazil by Stuart Pimm

Lovejoy and his team then surveyed the plots for the species they contained and watched, over the years, how they disappeared. “Many and quickly” was the simple answer, from work done with Tom by my former graduate student Gonçalo Ferraz. “We found that even in the largest fragments, many bird species were missing within a decade or so,” Ferraz told me. “The majority of the birds were gone from the smaller fragments in a matter of a few years.”

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Photo of land cleared at the site of Lovejoy’s experiment by Stuart Pimm

Would the same be true for forest fragments in Borneo that would be surrounded by oil palm plantations?

That was the question of a new experiment Dr. Robert Ewers, of Imperial College London, explained to me when I met him earlier this year. We sat in the dingy bar at Silwood Park where faculty and research students have crowded on Friday evenings for decades to discuss ecology’s latest ideas. It seemed a long way from Borneo’s rainforest.

Ewers had lots of good ideas to test–and, of course, the experiences and hindsight of what happened in Brazil. Would such species as orangutans and large birds, such as Borneo’s many species of hornbill be able to survive? I thought not, on the basis of what we’d learned in Brazil.

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Photos of black hornbill (above) and orangutan (below) in Borneo by Stuart Pimm

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The simple comparison of Brazil and Borneo was going to be important — a means to decide whether we really understood what had happened in Brazil and why.

I was looking forward to being in Borneo. When I finally got there, I talked to Dr. Glenn Reynolds, the director of the Royal Society’s Southeast Asia Rainforest Research Programme. The program has been based at the Danum Valley Field Centre since 1985.

He told me that they were about to establish a large forest fragmentation program. Large portions of forest will be planted in oil palm, but some areas will be kept as forest, however.

The sizes of those fragments will be the same as those in Brazil’s Biological Dynamics of Forest Fragments Project.

Working with their local partners in Borneo, the Sabah Foundation, researchers will spend two years surveying the areas for their biodiversity before the forest is cleared. This will establish the baseline.

Then after fragmentation, teams will follow the change.

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Photo of forest cleared for cattle pasture in Brazil by Stuart Pimm

Deciding how large fragments were needed to protect different kinds of animals and plants provided very important advice to managers in Brazil. We now knew that forest fragments had to be large enough if they were to protect biodiversity.

But there were many ecological variables that the Brazil project had not measured. The new experiments in Borneo would give scientists a chance to address so many questions they wished the Brazil project had tested.

“What will you measure?” I asked Reynolds. “Beetles, moths, butterflies–birds certainly,” he explained. “But one of the strategic aims of this project is to set up a platform, so that scientists in different disciplines from Malaysia and around the world can work on this problem.”

Reynolds plans were ambitious–but then there are so many things we need to know about what happens as humanity shrinks Earth’s tropical forests.

Watch Stuart Pimm’s video report and interview with Glenn Reynolds:

Professor Stuart L. Pimm is a conservation biologist at Duke University, North Carolina. A former member of the National Geographic Committee for Research and Exploration, Pimm is the author of dozens of books and research papers, including the book “The World According to Pimm: A Scientist Audits the Earth.”

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Photo Brazilian rain forest by Stuart Pimm

Read earlier blog posts by Stuart Pimm:

An Inordinate Passion for Moths

Florida Panther Fights for Survival Again–This Time in Washington D.C.

Many Mammal Migrations Are at Risk of Extinction, Research Finds

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