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The Silence of the Birds
The brown tree snake has wiped out bird life on Guam. Will a new snake virus curb the crisis?
Select text to jump ahead in the clip:
ALDA:
It's a tranquil scene
on the coast.
A couple of guys are
diving...
checking out life
on the lagoon floor.
People are boating.
Actually, I know
who that is out there.
She's Rachel Woodfield, a
marine
biologist, and she's bringing
in
a bag of that weed
the divers were looking at.
Hiya, Rachel.
Hiya.
Hi.
Is that it, there?
This is it right here.
ALDA:
But the weed is not as nice
as it might seem.
We're at Agua Hedionda Lagoon
just north of San Diego
on the California coast.
The divers out there
are trying to get rid
of every last shred of this
stuff that they can find.
It's calledCaulerpa
taxifolia.
It's an invasive weed
that has the potential
to literally smother
California's native
marine life to death.
We know that because
it's already killed off
thousands of acres of coastal
life in the Mediterranean.
Caulerpais a classic example
of the phenomenon that we're
devoting this entire program
to:
alien species.
Remember killer bees?
They're dangerously
aggressive
African bees
introduced to Brazil in 1957.
Now they've spread north into
California and the Southwest
and beekeepers are trying
to figure out
how to cope with them.
South American fire ants
are another alien.
They attack pets and wildlife
and destroy native plants.
Fire ants got to Mobile,
Alabama, in the 1930s
probably in soil
used as ship ballast.
Now they're in 14 states
in the Southeast.
What they all have in common
is that somehow
they've been transported
from their home habitat
to a part of the world
where they did not evolve,
where they're aliens.
It's a great thing
to be an alien
because in your new
environment
there aren't any of
the predators and competitors
that you originally evolved
with
that make your life
a constant struggle.
So you can really run wild
and grow like crazy
and take over the place.
Thousands of plants, animals,
insects, fish and microbes
have moved around the globe
to become aliens.
Almost always, it's humans
who do the moving.
Asian hydrilla, for example
was first brought to the U.S.
in
the '50s as an aquarium
plant.
Now it clogs waterways
all over the South.
People always have carried
things with them, of course
either by accident or design.
But now with global trade
alien species are becoming
an irresistible force.
In the Great Lakes, many of
the
most common species are
aliens
including the notorious
European zebra mussel.
Most are recent arrivals.
New Zealand now has as many
alien plants as native
around 1,700 of each.
Hawaii is the same.
It's thought that right now
the U.S. has about 7,000
alien species of all kinds.
Is that a bad thing?
Sometimes the cost is
obvious.
For example,
20% of California is infested
with Eurasian
yellow star thistle.
It's toxic to horses,
and cattle won't walk on it
so huge areas of rangeland
are now useless.
But ecologists argue
that the greatest costs
are less tangible.
When species get mixed up
in this great global exchange
the sets of plants and
animals
called ecosystems
can fall apart and disappear.
We're going to lk
at four alien species stories
from around the world.
Among them, they display
all the classic ingredients.
There's the 19th-century
Harvard professor
who thought he had the key
to a better silkworm.
There's the disease that
was blown across the Atlantic
to cause havoc in the
Caribbean
in coral reefs and maybe
among people as well.
We're going diving in the
Mediterranean to see
firsthand
the damage that
Caulerpa taxifoliacan do.
And first, the story
of a bird, a snake
and a small island
in the Pacific.
WOMAN:
Okay, this is...
ALDA:
This is the National Zoo
in Washington, D.C.
I'm heading for
the tropical bird house
in the company
of Kathy Brader, the keeper.
So, we have these birds
that are housed inside.
These are all
different...?
ALDA:
There's one particular
exhibit
we're interested in.
Now, this is
our Guam exhibit.
And in here we have
our Guam rail
and our brown tree snake.
He's curled up
on the top.
Oh, yeah.
And he is the cause
of these guys'
problems on Guam.
ALDA:
On the island of Guam
in the western Pacific
the forests are eerily
silent.
Guam has lost all three of
its
unique native bird species.
Six other regional species
are gone;
just three others
are hanging on.
This is the culprit.
You can see all the different
locks and equipment
we have on there to make sure
that he cannot get out.
Sometimes they hide
a key, you know.
(laughing)
Well, fortunately I don't
think we have that problem
with the snake.
And... let's just back up
here a little bit.
For us to have him here,
we had to have a special
permit
and only have males,
so there's no chance of...
If one did get out,
they can't reproduce.
Because we don't
need this problem
here in the United States,
you know, on the mainland.
ALDA:
You can be sure
that if the brown tree snake
did manage to get out
the Guam rail would
make an easy meal.
Guam has no native snakes
so the birds developed no
natural defenses against
them.
Horatio, as he's called,
doesn't even recognize
the nearby snake as a danger.
It's the mealworms
that interest Horatio.
BRADER:
We use them as
a protein supplement
but we also kind of
use them as a treat.
As a treat?
Yeah.
You know, no wonder
these birds are extinct.
Come here, Horatio.
ALDA:
Horatio is descended
from the last 21 Guam rails
that were brought in from
the wild in the mid-1980s
for captive breeding.
ALDA:
Do you hope
to reintroduce them?
BRADER:
Yes, but there's literally
millions of these snakes
and we can't just go
and re-release them
with the snakes still
being the problem.
When we can solve
that problem
is to reintroduce these
birds back into Guam.
We want them
in the wild.
NEWSREEL ANNOUNCER:
Here in the South Pacific
theater
air transport bucks fog,
mountains and Japs
in the routine performance
of its duties.
ALDA:
It was the disruption of war
that led to the devastation
of most of Guam's wildlife--
birds, bats, flying foxes
and small mammals.
The island was occupied
by the Japanese, fought over
and became an important
air-transport hub.
Sometime in the 1940s
a few brown tree snakes
must have stowed away on
flights
maybe from New Guinea
or the Solomon Islands
and made it to Guam-- the
first
snakes ever on the island.
Today, Guam is infested
with brown tree snakes
maybe one or two million
of them--
up to 20 snakes per acre
in some areas.
It's the highest snake
density
in the world
and a major nuisance for
people.
Their bite is only
mildly poisonous--
about like a bee sting-- but
the
snakes short out power lines;
they get into buildings
and attack anything--
wildlife, pets, chickens,
and children, too.
Secured in double cages
at the National Zoo
there's a large research
collection of brown tree
snakes
including females,
collected in Guam
by veterinarian Don Nichols.
He's been bitten
maybe half a dozen times.
You need
to move quickly
once they know
you're here
but I'm just going
to grab the snake
by the head
and secure the head,
which is where all
the weapons are
and then pull it on out.
And as you can see
these are very
long and slender
which is adapted
for life in the trees.
And if my hand were
a tree branch
then it could actually
extend its body out
as much as 67%
out into the air.
With a lot of snakes that are
not adapted to life in the
trees
you can actually
grab them by the tail
and hold them up like this
and the snakes can't get to
you
if you hold it away
from your body.
But this snake
can, huh?
But this snake
has the ability.
Its muscles are so strong
that it can actually come
right back up like this
and if I were
to let go of the head
it could come up
and nail me, or
maybe even...
Or maybe even me.
ALDA:
Guam is still a major hub
so the fear is
the snake could stow away
again
and jump to other snake-free
islands, like Saipan or
Hawaii.
There are rings of traps
around the seaport and
airport.
Cargoes are checked
constantly
but in spite of the
vigilance,
there are leaks.
So far the snake has been
caught
on eight other Pacific
islands
including Hawaii, where 14
are known to have arrived.
One snake was even caught
in Corpus Christi, Texas.
It's only a matter of time
before a new population
gets established somewhere
so the search is on
for some way to control--
even eradicate--
the snakes on Guam.
At the National Zoo
Don Nichols and Elaine
Lamirande
are working on a radical
idea:
find a disease
which just affects snakes.
These samples all came
from snakes that died
from a virus infection.
Called paramyxovirus,
it regularly crops up
in captive snakes
which live close together.
NICHOLS:
This one looks
a little rambunctious
so I'm going
to use the snake hook.
ALDA:
Don Nichols had the idea that
paramyxovirus could be made
to spread among Guam's
dense snake population.
Right now they're seeing
how different strains of
virus
sent here from around the
world,
affect the brown tree snake.
The snake gets
a shot of anesthetic
which takes about
15 minutes to take effect.
NICHOLS:
Now I give it a few jiggles
and make sure
there's no movement.
Yeah.
You can see.
I still will make sure
I got control of her head
but she's... quite asleep
at this stage.
ALDA:
Then a dose of one
of the paramyxovirus strains
is injected into
the snake's windpipe
causing a pneumonia-like
disease
within two or three weeks.
Don says these viruses pose
no risks for people
because they're active
only in cold-blooded
reptiles.
Our high body temperature
kills the virus off.
NICHOLS:
Let the fluid trickle down
into the lung.
ALDA:
So far they've tested 16
strains
of the virus, looking for one
that will kill the snake only
after a delay, so there's
time
for the infection
to spread to other snakes.
There's no getting
around the fact
that this project is about
killing animals-- figuring
out
the best way to give them
a really bad case of
pneumonia.
That's something that
an animal lover like Don
is acutely aware of
but for him,
it's the lesser of two evils.
How do you answer somebody
who questions whether or not
you're being cruel to them?
Well, I mean
it's all a matter
of your priorities
and I'm the first person
to admit...
I actually like snakes, and
I like them where they
belong.
But these things are... are
a pest species in an area
and they're causing
all kinds of havoc.
They're threatening
other islands.
And it may not be the most
humane way to kill them
but it's the only way you
can do it on a broad scale.
ALDA:
There was an attempt on Guam
to persuade people
to eat the snakes.
It never caught on,
and anyway
no approach involving
catching individual snakes
is going to make a dent
in a population of millions.
Don is convinced that only
a biological control agent
that can perpetuate itself--
like a disease or a
parasite--
could have much effect.
But could biological control
carry its own risks?
Don't viruses reproduce
rapidly?
Don't they have
a chance to mutate
and attack other species
eventually?
My biggest concern would be
whether or not it could
adapt...
mutate and adapt
to the native lizards.
ALDA:
Don says
that paramyxovirus has never
been known to jump to lizards
and of course they'll do
tests
before any virus release.
But biological control
inevitably carries risks
and that's a measure
of how difficult it is
to tackle the problems
created by alien species.
The original problem occurred
when some snakes got
on airplanes and flew to
Guam.
Now, if you infect
the snakes in Guam
and an infected snake gets
on an airplane
and flies to some country
where that virus could hurt
those snakes
isn't that a danger?
NICHOLS:
There is a chance
of that happening.
However, one of
the key things is
that these viral diseases are
very density-dependent.
In other words, high
populations, dense
populations--
easy for the viruses
to spread around.
But in the native range
of these things
it's very difficult
to find the snakes.
They're very
low-density, so...
It's not a zero-percent
chance,
I'm not saying...
No, no, I mean,
my mind is racing
because it just seems to me
that every time we do
something
to fix something that
we did wrong 50 years ago
we create a new problem
for somebody 50 years from
now.
ALDA:
The hope, of course, is
that we've learned
how not to create new
problems.
If the virus project is
approved
the small island of Rota,
35 miles north of Guam
may hold the best hope for
the return of Guam's
wildlife.
It's still free of snakes
so there are birds here
that are extinct on Guam.
Over the last few years,
more than 200 Guam rails
bred in zoos from the 21
birds
captured in the 1980s
have been released here.
Two-zero-eight-five.
ALDA:
They're breeding successfully
so they can provide
a wild nucleus
from which Guam itself
can be repopulated
if Don Nichols' virus works.
Guam's wildlife can
never be fully restored
but without snakes,
it can return
to something like the balance
that once existed.
And at the same time, the
threat
of similar devastation
spreading to other islands
can be averted.
Green Invader
Alien algae are smothering native marine life and livelihoods in the Mediterranean. And now it's in San Diego as well.
Select text to jump ahead in the clip:
ALDA:
How long have you been
studying thisCaulerpa?
MAN:
More than ten years.
Ten years.
ALDA:
We're in a small towjust down
the coast from Nice
in the south of France.
Alex Meinesz, a biology
professor from Nice
University
is taking me out fishing.
In those ten years,
how much has it
increased?
ALDA:
As with thousands of places
like
it around the Mediterranean
Sea
this town depends on a mix
of fishing and tourism
for its livelihood.
On peut monter?
FISHERMAN:
Okay.
Okay, thanks.
Bonjour.
FISHERMAN:
Bonjour.
Patrick.
Patrick, Alan.
Alex, bonjour.
Mais alors,
au commencement...
ALDA:
We're on the Verg family
boat.
The waters around here have
been
fished for generations--
until now, that is.
They don't fish here anymore.
We had to persuade them to
set
their net out last night
just so we could film
the result.
And the result is this.
ALDA:
There's some.
MEINESZ:
Caulerpa.
Yeah.
Caulerpa.
Look.
PATRICK:
On arrte un peu, uh?
Look-- and thisCaulerpa
clogs the nets
and the fish see the nets,
and there is no fishes.
Oh, I see.
So it hurts fishing...
it hurts fishing
just because...
They see the nets.
It calls
attention
to the nets.
ALDA:
The weed, calledCaulerpa
taxifolia,doesn't belong
here.
It's a tropical plant
common in the Caribbean
and other warm waters.
The northern Mediterranean
gets
cold in the winter
but somehow theCaulerpais
surviving and thriving--
nothing can touch it.
MEINESZ:
When you broke it, there
comes
a kind of juice out of, you
see?
Does that juice have
anything in it
that keeps away
predators?
Yes, absolutely
that are terpenes,
caulerpenynes.
And this is
a kind of toxic matter
and a repellent matter.
So the fish don't eat it.
So it repels fish,
and does it... so...
in this area, nothing is
a natural predator.
No. You see all
the leaves are entire.
Nothing...
Nothing has been
eating it.
No, no
eating trace.
Yeah.
On y va?
On y va.
(laughing)
Holy moly!
He really jumps in!
ALDA:
Alex took us
into the shallow water
near the town's bathing
beach.
Everything below was covered
by
theCaulerpa:rocks, sand, mud.
There's nothing else down
here--
no other plants, barely a
fish.
It's a classic example of
an alien that just takes
over--
like the brown tree snake
in Guam.
Nothing eats it,
and nothing competes with it.
It's full, huh?
Yeah, there's a lot
of it down there.
All the bottom is covered.
ALDA:
TheCaulerpaarrived here
about nine years ago.
Advancing at an inch a day,
it has ruined the fishing
and it'll soon clog
the town beach.
It's the same disastrous
story
spread out along a thousand
miles of Mediterranean coast.
Caulerpais easily spread.
It's carried along
in fishing nets
and there are millions of
small
boats in the Mediterranean
all with anchors.
MEINESZ:
A little piece like this
I put this in the water
after six months, you have
three square meters
with this little piece.
Any part of this?
Any part, any part.
ALDA:
With its rapid spread
from fragments
and its cold-water survival
Caulerpain the Mediterranean
is behaving
in ways that shocked marine
plant experts like Alex.
After years of investigation
Alex is pretty certain he
knows
how this disaster happened.
This is the aquarium
at the famous Monaco
Oceanographic Museum
where Jacques Cousteau
was once director.
In the early 1980s, the
museum
along with several other
European aquaria
started using a decorative
and easy-to-grow plant
in their tropical tanks.
The plant was
Caulerpa taxifolia.
It's still used here today,
as it is around the world.
Alex believes that somehow
some fragments ofCaulerpa
were released from the tanks
into the sea.
A museum diver
first sawCaulerpa
right outside the building
on the bottom in 1984.
It covered just one square
yard.
By 1989, when Alex first saw
it,
it covered two acres.
By 1990 it was
at nearby Cap Martin
next year Toulon,
a hundred miles away
and now it's found
from Spain to Croatia.
With no natural enemies
to hold it back
theCaulerpahas been
steadily smothering
Mediterranean sea life.
In the shallow areas, there's
normally a complex community
of over a thousand different
species: algae, shellfish,
worms
and fishes, all based
on meadows of native sea
grass.
In the darker depths,
there's a different balance
with the grass giving way
to red sea fans.
This is the steep 100-foot
rock wall off Cap Martin
once a favorite spot
for scuba divers.
The film is from 1996, shot
as theCaulerpawas taking
hold.
Alex has been diving here
every
year since
theCaulerpaarrived.
As the alien plant advances,
it blocks out light--
from the red sea fans,
for example, which die off.
Alex has seen the same
process
repeated all over the rock
wall.
Did this all originate
with the Monaco aquarium?
Genetic analysis has shown
theCaulerpais a mutant strain
unique to aquariums--
including Monaco--
and not found in the wild.
But we'll never know for sure
how it first got loose.
In the summer of 1999
our underwater cameraman swam
down the rock wall at Cap
Martin
to record the progress
of theCaulerpa.
The wall is now
completely covered.
The last sea fans are dying.
The wall is essentially
a biological desert.
Once again, we're looking
atCaulerpa
growing in an aquarium.
But there's something else--
it's a kind of slug
and it's eating the weed.
The result: all over the
tank,
ghostly white fronds of weed
with their toxic juice
sucked right out by the
slugs.
The slugs are being studied
in his lab
at the University of Nice
by Alex Meinesz.
In his view, they represent
the single best hope
for controllingCaulerpa
taxifoliain the
Mediterranean.
We've jumped 4,000 miles
across the Atlantic
to the Indian River in
Florida.
Alex's slugs came from here,
collected by Cecilia Miles
a marine biologist
from Florida State
University.
HereCaulerpais eaten
and controlled
by the highly specialized
slugs
as it is further south
all over the Caribbean.
The hope is that slugs
from Florida--
the northern extreme
of their range--
might be hardy enough to
survive
the Mediterranean winter.
In the summer of '99
Cecilia collected and packed
a batch of Florida slugs
for shipment to Alex in Nice.
The slugs had their own
air supply for the flight
and were escorted
across the Atlantic
by a French grad student.
See you, Cecilia.
Bye-bye. Thank you.
ALDA:
Here you were
a student
ofCaulerpa...
ALDA:
Alex has been studying
different slugs for years.
The Florida batch had been
in residence at Nice
University
for about two weeks
when I visited.
I study on
theCaulerpasince...
ALDA:
His work with slugs
andCaulerpa
is done on a shoestring
budget
in a makeshift lab
behind the biology building.
The Monaco Aquarium
connection
makes this
a very political subject
so research grants have been
hard to come by.
ALDA:
So you've got
a chance to see
who's working out.
Yes, who studies
biology.
Come in, please,
come in.
So... they're in there.
I don't see any slugs.
Yes... here!
ALDA:
Oh, yeah,
yeah, yeah!
Now, is he
eating now?
Yes, I think so.
So these slugs
really like
that toxic stuff.
Yes, ah, yes.
They need the toxic
because they take
the toxins
and they stock it
in them
and then the fishes
doesn't eat it.
Oh...
Oh, I see!
Oh, oh, so the slugs use
the toxins
to keep the fish away
from them!
Exactly, exactly,
exactly.
ALDA:
The slugs have other
highly specific adaptations
toCaulerpa.
They needCaulerpacells
as part of their own
metabolism
and they have a special tooth
which matches
onlyCaulerpacell structure.
Alex argues that the slugs
are so exquisitely adapted
to their one food
that releasing them
into the Mediterranean
to control the invasion
biologically
would present a very low
risk.
I asked him about this.
How do we know
the slugs that you
bring in won't adapt
and find some
other way to live
in addition toCaulerpa?
When the slug have
no moreCaulerpa
they cannot,
in one generation, say
"Ah, we shall change
our tooth, our mouth
our toxin, to eat
other things."
(laughing)
You understand?
That takes a lot
of plastic surgery!
You understand?
Sure, sure!
When there isCaulerpa,
they eatCaulerpa.
No problem, no problem.
When they see there is no
more
Caulerpa,it is too late.
It is too late.
ALDA:
Alex's slugs may be
the only way to go.
All kinds of nonbiological
control methods have been
tried
like releasing poisonous
copper
from underwater electrodes...
or simply
scraping the weed off...
vacuuming it up...
freezing it with dry ice...
scalding it with hot water...
or cutting off its sunlight.
But there's nothing that's
practical on a large scale
except the slugs.
I asked Alex again
is it really smart
to release the slugs
into such a paradise of food?
All of a sudden,
they're dining out every
night.
They're going to Maxim's
every night
and they're doing pretty
well.
Now you're liable to have
some pretty fat, happy,
healthy slugs around
looking for trouble.
No, no.
You ever have
a prairie ofCaulerpa
with many slugs in it
and then they control
theCaulerpa
and it is finished,
that we think.
But what you want?
Do you want to have
a Mediterranean Sea
full withCaulerpa
without any control method?
We must have a predator
for this invader.
Without predator,
theCaulerpa--
that is a risk that we see
now.
We can see, you have see it
when we snorkeling.
You see with the fishermen.
It covered all the bottom
and expands every year.
So what do we do?
Do we nothing
or do we try this?
ALDA:
If you can't get rid of it,
if the slugs don't work
if the slugs are too
dangerous,
if the slugs work
but governments won't let you
use the slugs
what will theCaulerpado?
What will happen
to the Mediterranean?
What happen is exactly
the same that happened
since ten years.
It extends.
It extends every year,
in new country, new regions.
And we think that this algae
is able to colonize
most of the region
of all the Mediterranean Sea.
ALDA:
Now fast-forward two years
and 7,000 miles.
We're back
at the California lagoon
where we began this program.
Just like in France,
the alienCaulerpahere
is untouched
by any natural enemy.
It's capable of smothering
the native eelgrass.
The patch
of bright greenCaulerpa
was first noticed
in the year 2000
suspiciously close
to a storm drain outlet.
Caulerpais widely used
in home aquariums
so someone probably dumped
one
out into a drain
somewhere in the area.
Getting rid of
theCaulerpahere
and in one more spot
near Los Angeles
is now the responsibility
of Rachel Woodfield
who works for an
environmental
consulting firm.
Where did you first find
Caulerpaaround here?
Right out here
in the eelgrass beds.
We were monitoring the
success
of the native eelgrass beds
and came across this bright
green terror growing in
there.
We weren't sure
what it was at first.
We've all heard ofCaulerpa
in the Mediterranean
but to make the relation
that this isthekiller algae--
it took us a little while
to figure it out.
Was it widespread by the time
you first discovered it?
It had spread throughout
this small harbor area.
It covers about five acres.
So we built this boom around
it
to keep all the boats out
and people who might want
to come in and see it
and might potentially spread
it.
ALDA:
They decided to try
killing off theCaulerpa
a few square feet at a time--
something it's too late for
in the Mediterranean.
Portable frames are covered
with plastic tarps
which are sealed to the
lagoon
floor with sandbags.
The underwater tent is then
given a dose of chlorine
and left for a few days.
Everything inside is killed--
Caulerpaand native eelgrass--
but so long as they get
all theCaulerpa
only eelgrass will grow back.
After a year,
it seems to be working.
We're at a manageable point
right now.
We have two infestations.
They're deep back inland
in lagoons.
There's calm water.
We're able to have the luxury
to put these tarps down
and deal with it
and keep an eye out for it
before it gets offshore.
Is this the major threat
or the only threat right now
from an alien species in
this...
in these waters?
This certainly is not
the first exotic species
that this lagoon has seen.
However, this is
the first species
that really has
the potential to cause
some serious, serious harm
to our coastline
and that is at a state
that is manageable.
The Silken Tree Eaters
Scientists wage a desperate struggle to save America's forests from deadly insects.
Select text to jump ahead in the clip:
ALDA:
We're in the New York City
borough of Queens
to witness the death of a
tree.
(chain saw buzzing)
ALDA:
One of the cemetery's prized
mature maples is coming down.
It was doomed anyway,
and this is why.
MAN:
What we have here is a larval
Asian long-horned beetle.
If we just pull him
out of here...
You can see
they're quite sizable.
They have
large mandibles
well suited
for the environment
inside a log
and chewing its way
through the hardwood.
ALDA:
The Asian long-horned beetle
is as big a threat
to America's forests
asCaulerpais
to our marine life.
In late summer
each female distributes
a couple of hundred eggs
around several trees.
The beetles arrived
in the mid-1980s
in wooden packing materials
from China
so as usual with alien
species
they have
no natural enemies here.
Right now they're just
confined
to the New York City
and Chicago areas
but already 7,500 trees have
had
to be destroyed.
The damage is done in the
spring
when the larvae hatch
and eat their way out
emerging as adult beetles
to begin the cycle again.
The tree cannot survive
the process.
You don't see much
on the outside sometimes
and then
when you flip it
you see what
type of damage
this is capable of.
Our goal is
total eradication of this
insect
from North America.
(chain saw buzzing)
ALDA:
Eradication means cutting up
every infected tree
picking out the larvae
chipping the remains
and burning the chips.
And then every apparently
healthy tree within 700 feet
gets a dose
of systemic insecticide
just in case
there are larvae inside.
Like withCaulerpa,
we still have a shot
at halting this alien
invasion.
The dominant hardwood
in the eastern American
forests
was once chestnut
until it was almost wiped out
by chestnut blight--
a fungus from Japan--
in the 1880s.
As a result, oaks took over
but they're being devastated
by the gypsy moth from
Europe.
So now maples are coming
to predominate.
But they're
one of the favorite foods
of the Asian long-horned
beetle.
It would be the worst-ever
pest
of American forests.
It's a pest
of about 18 different species
of hardwood trees
in the northeast forest
including all of your maples,
your elms, horse chestnuts
willows, poplars,
birch, ash trees.
So you're talking
about a sizable percentage
of the natural forest
in the Northeast.
And the possibility of spread
outside of the... if you
would,
the ornamental situation now
from a backyard pest to a
forest
pest, would be catastrophic.
ALDA:
Many people in the Northeast
have firsthand experience
of a continuing
forest catastrophe.
The gypsy moth regularly
defoliates and kills
large swaths of oak forest
in an ever-expanding area.
It's costly and destructive.
It leads to large-scale
pesticide use
and it's plain disgusting,
too.
The gypsy moth has been a
classic story of alien
invasion
for over a hundred years.
This film was made 50 years
after Etienne Trouvelot,
a Harvard astronomer
had accidentally released
a group of gypsy moths
from his home in Medford,
a Boston suburb.
He'd imported the moths
from Europe
in the hope of establishing
an American silk industry.
The first big defoliation
took place in Medford in 1880
ten years after the release.
There were more or less
constant attempts
to prevent the moth
from spreading
including extensive use
of toxic lead arsenate
sprays.
But by the late 1920s
it infested 40,000 square
miles
of New England, New York
and Canada.
Victory was declared
several times
but the gypsy moth
proved unstoppable.
Today, it's all over the
Northeast and still on the
move.
From this lab on Cape Cod
the U.S.D.A. continues
to battle the gypsy moth
as they have
for a hundred years.
Inside labs sealed with
airlocks
they keep gypsy moths
and about 40 other aliens
which might be the next
invader.
They even have some
Asian long-horned beetles
here.
They're determined not to be
caught off guard again.
MAN:
The gypsy moth is fully
entrenched in the United
States.
We will never eradicate it.
The goal now is to slow
that natural spread.
You can eliminate some
pesticide
use and save some dollars
by not letting u