Invasive Species Costing U.S. Over $130
land, put down firm roots
09/12/2002 , 2002 Page A9
Globe and Mail
YELLOW QUILL MIXED GRASS PRAIRIE PROJECT,
MAN. -- Gene Fortney has been driving
through southern Manitoba now for almost three hours,
and he's finally come to a piece of unbroken short-grass
He points from the rolled-down window of his '87 Chevy
to a subtle haze of yellow in the field in front of him.
"This is it. This is the ugly stuff," he says.
It looks innocuous enough up close, just a regular bunch
of leaves and forlorn yellow petals on a wiry stem.
But Mr. Fortney is a biologist with the Nature Conservancy
of Canada, and this plant, Euphorbia esula or leafy spurge,
has been his sworn enemy for a decade. It is killing the
little that's left of North America's wild prairie.
Leafy spurge is an invasive alien species, one of thousands
of biological intruders that have jumped from their home
turf to new parts of the planet -- including Canada --
and have done terrible damage.
Ten years ago, when world leaders at the Earth Summit
vowed to tackle the dangers facing the planet, invasive
alien species merited no more than a mention in the final
communiqué. The big issues then were extinction and
And while the warnings from Rio on those issues have
come horribly true over the past decade -- the climate
has officially changed as ever more greenhouse gases are
put into the air, and more species are on the brink of
extinction than ever before -- the threat of pest species
has turned out to be far greater than anyone imagined.
Invasive alien species are acknowledged to be a serious
and growing scourge that is wiping other species off the
face of the Earth.
Scientists call them biological pollution, or even biological
tumours because of their power to destroy other forms
of life. These intruders are plants, mammals, insects,
fish, mollusks and even viruses and fungi that have been
transported by design or accident into parts of the world
where they have no natural enemies. That puts the ecosystem
wildly out of balance.
"It's a litany of woe and misery. It's quite astonishing,"
said Bill Freedman, an ecologist at Dalhousie University
in Halifax who has written widely on this subject.
The most recent studies put the costs of damage from
just a handful of alien species in the U.S. at $137-billion
(U.S.). The costs to industry alone of Canada's most famous
alien species, the dreaded zebra mussel (Driessana polymorpha),
which has invaded the Great Lakes and some European water
systems, is roughly $1-billion since 1989 and counting.
Some of the aliens that have just arrived, or are inexorably
on the way, could inflict even more expensive damage.
Asian carp, which, like the snakehead fish, can make its
way across land if it needs to, is nearing the Great Lakes.
The brown spruce longhorn beetle, found in Halifax, would
devastate the boreal forest if it got the chance. And
the West Nile virus, already found in four provinces just
two years after it arrived in Canada, could be deadly
to some humans and livestock.
Though species have been imported as long as humans have
travelled (their invasions peak when human armies are
on the march), scientists did not begin to understand
the international scope of the problem until about five
years ago, Jeff McNeely, chief scientist of the World
Conservation Union (IUCN) said from his office in Gland,
Switzerland. Dr. McNeely is the world's leading scientist
on this topic.
The moment of truth came when the scientists looked at
birds and mammals that have gone extinct over the years.
"The No. 1 cause, where the cause is known, is invasives,"
Dr. McNeely said. They're also responsible for putting
a raft of species on the endangered lists, the biggest
cause worldwide next to habitat destruction.
The problem is becoming dramatically worse as global
trade ramps up. Canada, as one of the countries heavily
tied to international trading regimes through the General
Agreement on Tariffs and Trade and the North American
free-trade agreement, is one of the countries seriously
It's a costly problem.
Some of the direct price tag stems from the loss of productive
cropland and waterways to alien creatures that can't be
killed off. Other costs come from the price of chemicals
used to keep them at bay. Not to mention the unknowable
costs of destroying the native species that an intact
biological system needs to thrive.
Of all these tenacious and destructive species, leafy
spurge is a particularly worthy adversary, as Mr. Fortney
knows all too well.
He's standing on part of the 830 hectares of the Yellow
Quill project that he and Manitoba's Department of Agriculture
painstakingly assembled for the Nature Conservancy of
Canada over the past four years. It's one of the rare
and best swatches of native mixed-grass prairie left in
North America. Leafy spurge is eating it alive.
He's ticking off a list of what doesn't work to eradicate
the spurge. Eradicate, heck. Even slow it down.
You can't burn it out because it just grows back stronger,
he recites. It's not slowed down by mowing. The best known
herbicide for it, 2,4-D, hardly touches spurge but does
kill everything else that isn't a grass.
The spurge's complex tentacles of roots give off a toxin
lethal to every plant but itself, making it one the prairie's
worst neighbours and best spreaders.
No one has found a way to make money from the plant itself.
Cattle, the big-money livestock, avoid it like the plague.
Sheep and goats, the only livestock that can stomach its
corrosive sap, have little market value.
What if you rip it out of the ground?
"That just makes it mad," Mr. Fortney said.
Leafy spurge is an epidemic throughout the Great Plains.
So far, it infects more than 2 million hectares in North
America, including 35 states and most Canadian provinces.
In Manitoba alone, which is the worst affected part of
Canada, leafy spurge has all but taken over 136,000 hectares,
which means the land can support 16,500 fewer cattle.
Saskatchewan is nearly as afflicted, and British Columbia,
New Brunswick, Nova Scotia and a tiny chunk each of Ontario
and Quebec all have leafy spurge infections.
The plant probably came to the prairies with pioneers
in the late 1800s in oat seed brought from Russia, crossing
the evolutionary boundaries within which the plant had
developed over millions of years. The original infection
point for Manitoba is just a few miles from the Yellow
Quill conservation site in the tiny town of Wawanesa,
near the mouth of the Souris and Assiniboine Rivers.
By 1911, it had spread to Manitoba's wild prairie. Its
range has been doubling every 10 years since. Then, nobody
thought of it as a huge problem. The whole idea was to
conquer the wild prairie, root out the native species
and grow food.
Now, less than a century later, there's so little native
prairie that some of Canada's unique plants and animals
are in danger of disappearing. That's what Mr. Fortney
and the Nature Conservancy are trying to prevent.
There's a terrible irony in the history of this piece
of prairie. The Nature Conservancy bought its section
from the Mooney family, pioneers who had fled Ireland
to escape famine in the 1840s caused by the potato fungus
(Phytophthora infestans). That fungus, taken to Ireland
from North America, was one of the most infamous invasives.
Some of the worst mass killings of humans through history
have been caused by alien invasives. The bubonic plague
that killed 25 million Europeans during the 14th century
came from Central Asia, carried by invasive rats from
The great Inca and Aztec civilizations were destroyed
in part by the smallpox and measles viruses that the Spanish
brought to the New World in the early 16th century.
While those millions of people were helpless to fight
the invasives, scientists today are trying to do better.
Mr. Fortney and his crew have a full-time cowboy to herd
goats on the project, leading them to the worst spurge
spots where they gobble up the flowers and leaves.
The crew has let loose some beetles from the spurge's
home habitat in Eurasia. They eat out the spurge, at least
for a while. And the team is deliberately trying to spread
a type of moth that binds the spurge's leaves together
to form a cocoon and prevent it from spraying its seeds
throughout the prairie. They've got a line on a new herbicide
that might work.
All of this is experimental, though. It's not clear that
any of it will beat back the alien.
Similar biological fights are going on throughout Canada
and the United States against both old and new aliens.
They can be dramatic. The federal government leaped into
action recently to cut and burn about 5,000 red spruce
trees in Point Pleasant Park, an urban natural area in
Halifax, because they were infected with the brown spruce
longhorn beetle. The beetle attacks and kills healthy
spruce trees and could spread to Canada's vast boreal
forest if left unchecked, Prof. Freedman said.
It is thought to have arrived in Canada from Eastern
Europe about a decade ago in wood packing material.
More recent is the arrival of the West Nile virus from
Africa, carried by the culex mosquitoes. Ten horses in
Manitoba have died from the virus so far this year. Birds
throughout Southern Ontario and Quebec, and one in Saskatchewan,
have tested positive for it.
The virus, which can lead to fatal encephalitis in humans,
is thought to have been carried to North America in 1999
by infected birds. Mosquitoes feed on the infected birds
and pass the virus to other healthy mammals and birds.
As for the starling, the most abundant bird in the world,
it came to North America in the late Victorian era when
a gentleman's club in New York decided to do what it could
to make sure every species mentioned in the works of Shakespeare
could be enjoyed on this side of the pond, Prof. Freedman
said. It took several attempts, but the determined club
mates succeeded in introducing the starling, which quickly
began to kill off native birds by taking their nesting
"We're very, very naive about the ecological effects
of most of our actions," said Prof. Freedman, adding
that introductions of alien species often happen for whimsical
While it's clear that acting quickly to stop the spread
of an alien is one key way to fight it, prevention is
the best medicine, the scientists say, and it is a long
way from being universally prescribed.
New Zealand, with its fragile island ecosystem, has taken
the lead to protect its own borders with the Biosecurity
Act of 1993. Canada has done little to keep the harmful
species out, given the scope of the problem here, Prof.
"There are no substantive plans for dealing with
Globally, conservation experts are pushing for greater
controls on the deliberate and accidental movement of
Alien species invade North America
Located below are a few of the thousands of alien species
doing damage to North America. Unlike in their native
habitat, there are no natural predators here to control
these alien populations.
1. Purple loosestrife
Flowering plant came from Eurasia in early 1800s. Takes
over wetlands and farmlands.
2. Zebra mussels
Came from the Caspian Sea in the mid-1980's in the ballast
of a ship. They eat plankton so voraciously that there's
little left for other species.
3. Asian carp
Imported from China by fish farmers in the U.S. in the
1970's. Eats and reproduces so well it shoves out other
species. Great Lakes threatened.
4. West Nile virus
Came from Africa to North America in 1999, spread from
infected birds to healthy birds and mammals by mosquitos.
Can cause lethal encephalitis.
5. Common buckthorn
Arriving from Eurasia in the late 1800s, it was prized
as an ornamental shrub. Produces a poison in the soil
that keeps away native plants.
6. Brown tree snake
Originally from Australia, Indonesia and Papua New Guinea,
it arrived on military planes in 1940s. Eats eggs of native
7. Asian long-horn beetle
Arrived inadvertently from China as larvae in wooden
packing crates in mid-1990s. Infects and kills healthy
8. Snakehead fish
Came from Asia as aquarium fish and food in restaurants.
Can get across land, attack humans and eat small animals.
Takes over ecosystems.
9. Leafy spurge
Herb arrived from Russia in late 1800s as stray seed
in grain seed. Takes over endangered landscapes and reduces
10. Chesstnut blight
Fungus imported to the U.S. on Japanese chestnut trees
in 1876. Has destroyed millions of hectares of the once
abundant native chestnut.
11. Starlings (entire map)
Brought over from Europe by Shakespare fans wishing
to fill N. America with species from his plays. Spreads
wildly, taking other birds' nesting space.
The road from Rio
Canada and the environment, 10 years after the Rio Earth
-*Today: Attack of the alien species
-*Monday: Fish depletion: Our great biological
-*Tuesday: A Canadian city's bid to save the