By JON CHRISTENSEN
Conservationists call them hot spots — habitats that cover just 1.4 percent of
the earth's land surface but are so rich in biological diversity that preserving
them could keep an astonishing number of plant and animal species off the
endangered list.
Since 1988, when Dr. Norman Myers and his colleagues began describing these hot
spots in a series of scientific papers and arguing for their protection, they
have become a focus of worldwide conservation efforts. Private organizations and
government agencies, including the World Bank, have made preserving 25 such
ecological arks — from the Atlantic rain forest of Brazil to the semiarid
Karoo region of South Africa — a top priority for financing and protective
legislation.
But a growing chorus of scientists is warning that directing conservation funds
to hot spots may be a recipe for major losses in the future. Just as an investor
should maintain a balanced portfolio, the scientists argue, conservationists
should avoid putting all of their eggs in one basket.
Hot spots are top performers in one dimension, these scientists say: the number
of unique species that live in them. Of species that live on land, nearly half
of all plants and more than a third of all animals are found only in the hot
spots. But they do not include many rare species and major animal groups that
live in less biologically rich regions ("cold spots").
And the hot-spot concept does not factor in the importance of some ecosystems to
human beings, the scientists argue. Wetlands, for example, contain just a few
species of plants, but they perform valuable service by filtering water,
regulating floods and serving as nurseries for fish.
This debate has been simmering quietly among biologists for years. But it is
coming to a boil now with the publication of an article in the current issue of
American Scientist arguing that "calls to direct conservation funding to
the world's biodiversity hot spots may be bad investment advice."
"The hot-spot concept has grown so popular in recent years within the
larger conservation community that it now risks eclipsing all other
approaches," write the authors of the paper, Dr. Michelle Marvier, a
professor of biology at Santa Clara University, and Dr. Peter Kareiva, an
associate at the university and a scientist with the Nature Conservancy, a group
that has increasingly focused on hot spots.
"The officers and directors of all too many foundations, nongovernmental
organizations and international agencies have been seduced by the simplicity of
the hot spot idea," they go on. "We worry that the initially appealing
idea of getting the most species per unit area is, in fact, a thoroughly
misleading strategy."
Other prominent ecologists have grown critical of hot spots. "Focusing all
of our attention on hot spots is just nuts," said Dr. Paul Ehrlich,
president of the Center for Conservation Biology at Stanford University.
"The hot-spot approach was a good one when it was proposed by Myers way
back when," Dr. Ehrlich said. "It attracted important attention to the
distribution of species diversity. Now it's clear that saving a few percent of
the earth's surface to preserve species will not accomplish what needs to be
accomplished."
Even if people succeeded in preserving a single viable population of every
species on earth, he said, the human race would die out unless it managed to
protect the ecosystems that support broader populations of plants, animals and
people too.
"One has to balance the necessary attempts to preserve species diversity
with what may be much more important," he said of "the preserving of
population diversity and in the process the preserving of ecosystem
services."
But hot spots have their ardent defenders, notably Dr. Myers, a fellow at Oxford
University, and Dr. Russell Mittermeier, president of Conservation
International, a nonprofit organization that has made hot spots the centerpiece
of its global strategy.
Dr. Mittermeier says hot spots have been successful at attracting attention and
financing for conservation in tropical countries. "And that has been
good," he said. "No one is suggesting that one invest solely in hot
spots, but if you want to avoid extinctions, you have to invest in them."
By definition, hot spots contain many species that exist nowhere else on earth
and that are under threat because more than 70 percent of their habitat has been
destroyed. Conservation International is still working on expanding the hot
spots list, Dr. Mittermeier said, with 10 new ones to be announced later this
year.
And the organization puts a high priority on protecting five vast wilderness
areas that have many unique species and are still relatively intact. They
include the world's largest tropical rain forests, the Amazon, the Congo forests
of central Africa and the island of New Guinea, as well as the Miombo-Mopane
grasslands and woodlands of southern Africa, and the deserts of northern Mexico
and the American Southwest. These areas still have more than 75 percent of their
natural habitat and fewer than 13 people per square mile, said Dr. Mittermeier,
but they will become hot spots if they are not protected,
Dr. Myers said that since he wrote his first paper on hot spots, $750 million
had been committed to protecting them, including a $261 million donation to
Conservation International from the Gordon and Betty Moore Foundation, the
largest single gift ever to an environmental organization. Still, he said, the
hot spots need more attention and more money — "a lot more," he
said.
Dr. Agnes Kiss, an environment specialist with the World Bank, acknowledges that
when it comes to spending money on conservation, hot spots loom large. "Put
it this way," she said. "When we're trying to justify a project, if
it's a hot spot, basically it's a shoo-in."
The World Bank and its Global Environment Facility, which makes grants in
addition to the bank's traditional loans, is halfway through a five-year $125
million Critical Ecosystems Partnership Fund to invest in protecting hot spots,
along with the MacArthur Foundation, the Japanese government and Conservation
International.
Still, Dr. Kiss said, the bank also takes other factors into account, including
the commitment of governments and local communities to preserve biodiversity and
their track records with previous projects.
In a world where funds are limited, that is just the kind of approach that is
needed, Dr. Marvier and Dr. Kareiva assert in their American Scientist article.
In a coming paper in Ecology Letters, written with their student at Santa Clara
University, Casey O'Connor, they propose a "return on investment"
model to determine which countries provide the best opportunities for preserving
biodiversity. Their analysis compares the feasibility and cost-effectiveness of
conservation efforts in different countries, alongside biological diversity and
the threat of habitat destruction.
When factors like the costs of doing business, the reliability of governments
and pressure from population growth are taken into account, they write, some
countries on Conservation International's list of the 17 most "megadiverse"
countries — Colombia, Ecuador, Indonesia, and Venezuela, for example — drop
off the priority list. And some other countries not found on the list emerge as
priorities, including Argentina, Bangladesh, Mozambique and Vietnam.
Still others appear on every list, no matter which priority-setting model is
used: China, India, Madagascar, Papua New Guinea and South Africa.
Dr. Marvier and Dr. Kareiva say the largest conservation organizations — the
Nature Conservancy, the World Wildlife Fund and Conservation International —
have many offices concentrated in countries with hot spots, but are understaffed
in countries with vast biological resources, like Argentina and Russia.
Since no one strategy is enough, they argue, conservationists need a way to make
explicit trade-offs. Preserving 1,000 species in a "cold spot" like
Montana, they argue, would be more important than preserving 1,000 species in a
hot spot like Ecuador because in Montana 1,000 species represents a third of the
total, while in Ecuador it represents just 5 percent.
"Conservationists widely accept the need for some sort of triage,"
they argue, "whereby limited funds go to places where the greatest good can
be done."
Dr. Kareiva acknowledged that there would never be one magic equation everyone
would accept. "But we can all get more sophisticated by focusing on
different variables," he said. Biological diversity, he said, "should
be one variable in the equation; it shouldn't be the end-all or be-all."
Dr. Kiss, the World Bank environmental specialist, agreed. "The basic
principle that biology isn't everything is quite sound," she said. But Dr.
Mittermeier of Conservation International worries that focusing on "return
on investment" could lead to bad decisions in the long run. Colombia, for
example, demands conservationists' attention despite the uncertainties raised by
its guerrilla war, he said, adding, "If a country is rich in diversity it's
very dangerous to write it off because of temporary difficulties."
Dr. Thomas Lovejoy, president of the H. John Heinz Center for Science, Economics
and the Environment in Washington, called the debate "useful, but somewhat
academic."
"The real issue here is not the sort of fine-tuning of what is the best way
to set priorities from organization to organization. It's about changing the
scale of the funding," he said. "In the real world, there is a real
need for a diversity of approaches in the field of conservation."
Hot-spots research "highlighted that there are certain places where the
fire engines ought to go right away," Dr. Lovejoy said, "whereas other
places under less pressure can wait a few years, if you have to do them in
sequence."
"But you'd better not wait too long," he added.
http://www.nytimes.com/2003/07/01/science/earth/01COLD.html
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