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FOREST CONSERVATION NEWS TODAY

Deforestation Linked to Regional Weather Change

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Forest Networking a Project of Forests.org, Inc.

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10/19/01

OVERVIEW & COMMENTARY by Forests.org

Widespread forest clearance disrupts regional climate reports the

journal Science. Long hypothesized, events in Costa Rica, West

Africa and elsewhere are making it abundantly clear that habitat loss

disrupts weather for long distances. Destruction of terrestrial

ecosystems ripples through climatic, marine and aquatic ecosystems.

Attempts to conserve species, including our own, are meaningless

unless widespread natural ecosystems are preserved and restored.

g.b.

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Title: Deforestation Far Away Hurts Rain Forests, Study Says

Source: Copyright 2001 Los Angeles Times

Date: October 19, 2001

Byline: GARY POLAKOVIC, TIMES ENVIRONMENTAL WRITER

Weather itself is changing in the lush cloud forests of Costa Rica

because of deforestation many miles away, scientists say in a new

study published today in the journal Science

The changes threaten diverse plant and animal communities as well as

assumptions behind an effort to save the world's best remaining rain

forests. Up to now, the changes have been blamed on El Nino or global

warming. But the latest findings indicate that as trees on Costa

Rica's coastal plains are removed and replaced by farms, roads and

settlements, less moisture evaporates from soil and plants, in turn

reducing clouds around forested peaks 65 miles away.

At risk is an ecosystem atop a Central American mountain spine that

provides valuable services to people and nature. It is home to the

Monteverde Cloud Forest Reserve, one of the world's most famous cloud

forests and a linchpin of the nation's tourist economy. A realm of

moss and mist, the woodland in the clouds--a type of rain forest--is

home to more than 800 species of orchids and birds, as well as

jaguar, ocelot and the Resplendent Quetzal, a plumed bird sacred to

the Mayans. It is also a watershed that supplies farms, towns and

hydropower plants in the lowlands. The findings are consistent with

similar localized weather changes seen in deforested parts of the

Amazon region. Scientists say that cloud forests in Madagascar, the

Andes and New Guinea are also at risk. Those environments account for

a small portion of the Earth, but they harbor a disproportionate

share of the planet's plant and animal species.

"These results suggest that current trends in tropical land use will

force cloud forests upward and they will thus decrease in area and

become increasingly fragmented and in many low mountains may

disappear altogether," the scientists conclude.

The findings are the work of a team of researchers at the University

of Alabama and Colorado State University.

"It's incredibly ominous that over such a distance deforestation can

alter clouds in mountains. This is a very serious concern," said Gary

S. Hartshorn, president of the Organization for Tropical Studies, a

consortium of rain forest researchers at Duke University.

"This is confirmation of what we have predicted for a long time,"

said Stanford University ecologist Gretchen Daily. "The implications

are very serious for the tropics and other parts of the world."

Using data collected from satellites and computer models, scientists

examined how forest clearing along the Caribbean coastline--more than

80% of lowland forests there have been cleared for farms and towns--

influences weather downwind in the Cordillera de Tilaran mountain

range. Evaporation from lowland vegetation is a principal source of

moisture for the 4,000-to-5,000-foot mountains during the dry season

of January to mid-May.

The researchers found that the moisture content of the clouds over

the mountains has declined by about half since intensive land

clearing began in the 1950s. Also, the cleared land is warmer,

pushing the base of clouds nearly a quarter of a mile higher on some

days, meaning they pass over the mountain range dropping little

moisture. In contrast, clouds were more abundant over forested

lowlands just across the border in Nicaragua, where forest still

blankets much of the coastal plain, the study says.

"Deforestation has effects which may be much broader than the

immediate deforested areas. Mountain forests that are protected may

be affected by what's happening some distance away," said Robert

Lawton, tropical rain forest ecologist at the University of Alabama.

Each year about 81,000 square miles of tropical forests are cleared,

Hartshorn said.

The findings in the study complicate a worldwide effort to save the

most biologically diverse and most threatened remaining tropical

forests. Many scientists have endorsed a plan to save 25 of the

world's biodiversity "hot spots." Those regions, which include parts

of Southern California, Africa, the Amazon and Asia, constitute just

1.4% of the Earth's land mass. Yet they are believed to harbor about

60% of the world's plant and animal species. Washington-based

Conservation International, a nonprofit group leading the campaign,

says protecting those lands will cost an estimated $24 billion.

However, the study in Science suggests that even protected lands

seemingly removed from human encroachment are vulnerable to localized

climatic shifts. The problem is also compounded by global warming,

which many scientists agree is being caused in part by fossil fuel

burning.

"This is going to be a big problem," said Gustavo Fonseca, vice

president of science for Conservation International. "We can't only

hold these tiny pockets of native habitat and hope they will survive.

We have to look at these areas planned for protection and realize

that unless we change our use of the landscape we could still lose

them."

More research is planned in Costa Rica. In the next phase, scientists

using a $480,000 grant from NASA plan to fund a three-year follow-up

study, which will include installing instruments to measure rainfall,

inventorying plants and animals in the cloud forest and studying the

impacts on the Pacific side of the mountain range.

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