Stanford Report, February 16, 2001
BY LOUISA DALTON
Plants have
no respect for boundaries. Nor, for that matter, do zebra
mussels, crazy ants or Nile perch. When alien species
invade, they wreak havoc on economies and ecosystems
across the globe. Curbing the problem is an international
task, says Harold A. Mooney, a Stanford biologist who
helped design a global plan to deal with the invaders.
“If we have a fire, then we send for the fire truck.
People respond right away. But we have no strategy for
invasive species,” says Mooney, the Paul S. Achilles
Professor of Environmental Biology. On Friday, he
outlined a 10-point strategy to curb invasive species at
the American Association for the Advancement of Science
(AAAS) conference.
Salvinia
molesta, or "Kariba Weed", an invasive plant
species, in Lake Kariba, Zimbabwe
Photo: H.A.B. Simons
Mooney spoke
on behalf of the Global Invasive Species Programme
(GISP), an international collaboration of scientists,
lawyers and policy makers that has been working for three
years to come up with an effective and globally
acceptable plan.
Behind habitat destruction, alien invasion is the second
greatest cause of species extinction worldwide. On
islands, alien invasion is the number one cause of
extinction, says Laurie Neville, project officer for
GISP.
When the small brown tree snake arrived on the coast of
Guam, it entered an island with 13 species of forest
birds, 12 types of lizards and three bat species. Today,
only one bat species remains, three forest birds and six
native lizard species.
Biodiversity loss, though devastating, is not the only
issue. More than one million nocturnal brown snakes now
inhabit even the smallest spaces on Guam. They cause
blackouts by crawling on power lines, hunt in family
chicken coops and slide into homes through bathroom
vents.
Guam may sound extreme, but many examples rival the
plague-like status of the brown tree snake. The invasive,
hardy water hyacinth strangled the ecosystem and
economics of Lake Victoria in Africa until a
multimillion-dollar international control program was put
into effect. Crazy ants form supercolonies in the
rainforests of Christmas Island, changing the habitat and
preying on the animals of the forest floor. The alien
star thistle outcompetes native desert grasses of
California. “The rangelands of the west are being
taken over by noxious weeds causing enormous financial
loss,” Mooney says.
The human propensity to travel – carrying plants,
animals and bacteria – is essentially taking our
ecosystems back some 200 million years, when the
Earth’s land masses consisted of a supercontinent
called Pangea. During that era, plant seeds and animals
could move freely across the land, since they were not
yet separated by thousands of miles of ocean. Mooney
dramatizes the long-term consequences of alien invasion
by holding up a picture of the continents as Pangea once
again.
Currently there is no global network set up to deal with
or prevent future ecosystem invasions. “We’re
looking at designing something like the CDC [Centers for
Disease Control],” says Mooney. “We need
something comparable for invasive species.” He
introduced the 10 elements of the GISP global strategy
-– a “framework for mounting a global-scale
response” – at the AAAS symposium.
Mooney described the need for a “rapid response
mechanism” – a fire truck for invasive species.
If nations develop the resources to react immediately to
an invasion, they will save money and time by controlling
the invasive species before it establishes itself.
Mooney also addressed the crucial need for developing
international financial checks and balances. “If you
import something, and it gets away, you should help
pay,” Mooney says. He suggests adopting a type of
bond, or insurance system, where those who do the
importing contribute to a fund set aside to fight harmful
invasive species. The GISP strategy also recommends
considering the actual cost of invasives and
incorporating that cost into a financial code of conduct
for the importers.
One of the most controversial areas, Mooney says, is the
legal arena. “There are a lot of holes and
inconsistencies” in current national and
international law touching invasive species, he notes.
The goal is to create consistent laws, whether in the
export country, the import country, or both, that help
minimize the introduction of alien species.
To synthesize three years of research and finalize the
10-point global strategy, Mooney met with other
biologists, along with economists, lawyers and policy
makers from around the world in Cape Town, Republic of
South Africa, this past September. “This is a
consensus,” Mooney says.
Whereas in the past, the invasive species issue has
partitioned people in agriculture, shipping and
government, “that meeting in South Africa was a
coming together,” notes Mooney. “It was a
breath of fresh air.”
Louisa Dalton is a science writing intern with Stanford
News Service.
The human propensity to travel -- carrying plants, animals and bacteria -- is essentially taking our ecosystems back some 200 million years, when the Earth's land masses consisted of a supercontinent called Pangea. During that era, plant seeds and animals could move freely across the land, since they were not yet separated by thousands of miles of ocean. Graphic: Anna Cobb
