Sitting in the stern of his sturdy gray lab boat, David Lodge
is sexing crayfish.
Reaching into a white plastic bucket, he plucks a rusty crayfish
from the tangled mass of scratching, frothing, gnawing crustaceans.
The angry critter waves his pincers in futile menace as the Notre
Dame ecologist applies his calipers with practiced ease.
Jody Murray sits amidships, clipboard ready. The rookie Notre
Dame grad student is on her first crayfish roundup, where the
numbers of northern crayfish and the invasive crayfish called
rusties are being tallied in Lake Ottawa on Michigan's Upper Peninsula.
She swiftly tallies as Lodge calls out carapace length, sex, molt
status and the occasionally indignant "Ow!" when a claw makes
it through his defenses. "All rusties," he declares after the
last one, then revs the motor and bears down on the next buoy.
It may be an overcast July day in the Upper Peninsula, but skimming
across the light chop on Lake Ottawa it's hard to avoid the seductive
tune of this little gem of a northern lake. Martial spruce, shimmering
aspen and bright maple rim the bluish green water, which is clear
to a depth of 20 feet. The bottom is a jumble of rocks and the
occasional log, and it seems each crevice conceals yet another
crayfish.
Forty traps were set yesterday, each baited with a half pound
of beef liver. Pulling the next, Lodge keeps a hopeful eye for
the northern crayfish, the native in these parts. In 1931 a survey
of northern Wisconsin and Michigan found no rusties, but by 1960
the Ohio Valley rusty was common.
Most people can't tell the rusties from the northern crayfish,
but they can see the difference in lakes invaded by the rusty.
A 1937 study of Lake Ottowa, for example, detailed an underwater
tapestry of submerged plants, 14 species in all. These floating
nurseries were hearth and home to countless game fish striving
for eventual big-fish status. That refuge was shredded in the
last decade as the rusties became dominant; only a single species
of submerged plant holds on in a small bay. Drop live bait and
you're as likely to pull up a rusty crayfish as bass or walleye.
According to Jerry Edde, fisheries manager for the Ottowa National
Forest, such invasive species as the rusty crayfish are the single
biggest threat to this legendary fishing landscape.
By day's end we've loaded two coolers. The score: invasive species
1871; native species 0. The invasive species can't go back in
the lake, so science steps aside for the culinary arts. We cull
out the big ones and make a shopping list: garlic, butter and
-- as a precaution -- more ice. The rusties are plenty cool for
food safety, but Lodge wants them comatose before we get back
to the protected lakes at the University of Notre Dame Environmental
Research Center (UNDERC). The research center is on the Wisconsin-Michigan
border, and there are no rusty crayfish in any of the 30 lakes
on the site. Lodge intends to keep it that way.
* * *
Trapping crayfish brings David Lodge back to his roots. In 1983
he was a young post-doc at the University of Wisconsin, a freshly
minted Rhodes Scholar in search of a research topic. His adviser
suggested the rusty crayfish, and Lodge began the trapping that
continues today. "You got to see a lot of lake, and you didn't
have to think too much," the ND professor of biological science
recalls. "Except for the time I thought I was going to die on
Trout Lake. It was one of those summer thunderstorms. I could
see it coming; I just couldn't go fast enough."
He escaped, of course, bringing his crayfish work to Notre Dame
in 1985 and delving ever deeper into the burgeoning field of invasion
ecology. Ecologists identify a handful of major threats to global
biodiversity: climate change, nitrogen pollution, and overharvesting
of forests and fisheries, among others. Also high on the list:
invasive species. These are organisms that have colonized new
territory to devastating biological effect, displacing native
flora and fauna and remaking natural systems in their image. "There
is a strong consensus among ecologists that this should be one
of the major environmental concerns of our day," says Lodge.
But it's a difficult problem to grasp. Each invasive species
is a fresh face, traveling via different pathways and affecting
different terrain in different ways. "In aggregate, the effect
is an enormous change," explains Lodge. Invasions are a natural
part of evolution, but modern transportation has radically increased
the rate at which organisms are being moved around, the distances
they can move and how fast they get there, alive. "Invasions and
other environmental things tend to have built-in delays," he says.
"It's often hard to know what the result is going to be for 10,
20, even 100 years."
The effects are varied too. For example, the native crayfish
in Lake Ottawa are widespread; their absence here does not even
begin to threaten extinction. Yet invaders can significantly alter
our experience of place.
"I've always loved snorkeling in patches of underwater plants,"
Lodge says, thinking of Lake Ottawa. "It's sort of the aquatic
equivalent of a walk in the rainforest. That's where the biological
action is in lakes. Plants create this forest, this structure,
food for all the other organisms to eat. Any angler knows that's
where you go fishing. The rusty crayfish clearcut that underwater
forest, which has an immediate effect on one of the things that
people value about lakes. If you have grown up in a place, or
lived in a place for a long time, you appreciate whatever is unique
and distinctive about where you live. That includes the plants
and the animals and the way the lakes look."
The overall price tag is huge, and the economic impacts varied.
In 1999 Cornell ecologist David Pimentel estimated annual damage
in the United States at $123 billion. Alien weeds clog wetlands
and western rangeland at a cost of $35.5 billion; these figures
include reduced productivity of pasture for livestock and of wetlands
as fish and wildlife nurseries. Foreign insect pests cost $20
billion in direct damage to crops and property. Organisms causing
human disease run a $6.5 billion tab for prevention, monitoring
and lost productivity. Beyond the economic damage, more than 40
percent of species on the U.S. Department of the Interior's endangered
or threatened species lists are there because of invaders.
With that kind of money at stake, the Clinton administration
finally took note, issuing an executive order in 1999 for cabinet-level
coordination of the battle against invasive species. On a visit
to the capital that year Lodge stopped by the coordinating office
to see how things were going; the next year he was selected as
the first to chair the scientific advisory committee. He remains
a member today.
In an era of sharp partisan conflict over environmental issues,
Lodge seems almost relieved to report that where invasives are
concerned traditional enviro-political boundaries do not apply.
"The full support that both the Clinton and the Bush administrations
have given this issue reflects how serious it is."
"He's made some really important contributions in bringing the
science of species invasions together with the policy for dealing
with them," says former Notre Dame colleague Steve Carpenter,
a highly decorated lake ecologist now at the University of Wisconsin.
"That's not easy to do."
Still, warns Lodge, "There is not enough being done on any level:
local, state, federal or internationally." New Zealand, Australia,
South Africa and Norway are all more advanced. The American political
system makes implementation of safeguards different and harder.
"It will require collaboration of local communities, states and
the federal government," says Lodge. The federal government can't
-- and shouldn't -- do it alone, but it does need to provide the
coordination and start-up resources to states.
And while ecologists bring a special expertise to bear on the
problem, Lodge is not asking for final say. "I want to tell people
about how the world works, about what organisms have lived here
in the past, and haven't lived here, and what effects might occur
if you introduced, for example, bighead carp into the Great Lakes.
But once I've told people that bighead carp came from Asia and
that they might cause great damage in the Great Lakes, it doesn't
follow immediately or inevitably that bighead carp shouldn't be
allowed into the Great Lakes." Somehow, society must weigh the
net effects. "That's what our political system is all about."
* * *
En route to UNDERC, Lodge detours to Boulder Junction, Wisconsin,
the nearest town center. Housing is tight at UNDERC, so some students
are renting a home next to the Flambeau River, where they've located
another invader, the Chinese Mystery snail. How did a Chinese
delicacy wind up in a wild Wisconsin river? Probably from the
booming live food trade. "If you go into any major American city
you can buy all kinds of things that are alive," says Lodge. "It
will blow your mind." Riverside, he pulls a few off the dock pilings,
but they're small. Spying some larger specimens across the way,
he strips off his shirt and wades in to collect the second course:
escargot.
Back at his cabin, the edibles are deposited in the kitchen
while the smaller crayfish are immediately placed in deep freeze
in the lab. Once dead, they'll be disposed of off-site. The Notre
Dame facility, with 30 lakes behind lock and key, makes a perfect
reference site for Lodge's work. With access strictly controlled,
the lakes are not likely to be invaded, and Lodge doesn't want
that to change.
After a few Internet searches on the preparation of snails,
the crayfish are ready for the pot. Lodge's crew -- three graduate
students and their summer assistants -- begin to arrive, bearing
bread, salad, Alfredo sauce and spaghetti. Soon bowls of steaming,
lobster-red crayfish reach the table and body parts begin to fly.
They're on the small side, but once extricated, the kernels of
white flesh are as succulent as their Maine and their Louisiana
cousins, which Southern locals call crawfish.
The students are relaxed in the company of their boss and mentor,
though a few remain suspicious of the main course; fewer sample
the snails. It could be worse. While in Kenya to study the impacts
of Louisiana crayfish, Lodge treated his Kenyan technicians to
a crayfish lunch. "I thought it would be fun, but they refused
to even take a bite," he says, confirming another complication
of invasives: One man's trash is another man's treasure. "The
idea of eating crayfish was so repulsive to them, they couldn't
do it."
Louisiana crayfish in Africa provide another wrinkle to the
invasive tale. Brought in by British colonials, now they're being
explored as possible biological controls for the snails that harbor
schistosomiasis. There are more than 200 million people with this
devastating tropical disease; 10 percent die every year.
Despite the promise, Lodge's work indicates there could be unintended
consequences. East Africa's Lake Victoria has already lost untold
species to invasive -- and ravenous -- Nile perch. "There is so
rich a biological heritage in Lake Victoria that we should put
a high value on protecting it from yet another species," says
Lodge. "On the other hand, it's awfully difficult to weigh those
kinds of damages against the potential benefits of reducing disease."
This tension is writ large on the American landscape. Of the
30,000 exotic plants, animals and microbes already in the United
States, only a tiny percentage are considered invasive and harmful.
Many more provide net economic benefits. In the absence of a comprehensive
strategy or policy, thousands more enter every year without forethought
or review.
"There are environmentalists that say we have to reduce the
risk to zero, but I think this is neither a practical nor theoretical
option," says Lodge. It's simply too expensive. As lead investigator
on a $3 million National Science Foundation grant, Lodge is trying
to refine a cost-benefit analysis to help simplify policy choices.
For example, given a freshwater lake with a power plant drawing
cooling water, what is a rational investment to prevent the spread
of zebra mussels into the lake? Over five years, the answer is
nothing; the likelihood of a damaging invasion is too small. But
use a 25-year time horizon and it becomes rational to invest heavily
in protection.
"Our political system, for all it's unbelievable strengths,
tends to lead people to take a short-term perspective," argues
Lodge. "One of the things I think ecologists and environmentalists
often bring to the table is a long-term perspective." Consider
homeland security. A biological attack -- anthrax or smallpox,
perhaps -- is really just a subset of the invasive species problem.
Whether you're talking about weaponized smallpox or zebra mussels,
they all grow and spread governed by the same biological rules
and processes.
"We've been suffering from biological damage from other nations
for centuries, and increasingly so in recent decades," notes Lodge.
That's why the Centers for Disease Control ad Prevention has the
power of quarantine against threats like SARS and monkeypox, while
agricultural authorities can burn entire groves to stamp out citrus
canker. But protecting native ecosystems is just not on the radar.
"We are suffering death by 1,000 nicks from invasions that happen
every day, that are both intentional commercial activity and unintentional."
As we invest heavily in homeland security, says Lodge, we should
focus not only on the "risk to human health, but to things that
pose a threat to our natural ecosystems as well, which we value
in the long run just as highly. If you're looking for packages
the size of a dirty bomb, it should be equally easy to look for
organisms, things that are not intentionally a threat or a weapon
but, nonetheless, are likely to cause great damage."
* * *
There is a certain calm that envelops many people on a northern
lake, a sense of well-being, of life well-lived, a sneak peak
at paradise. The sky reflected atop bottle green depths. The clean,
enveloping water. Air scented with pine and a hint of fresh fish.
A gentle chorus of birds and frogs and wind in the leaves.
This is what many would call a sense of place. By the end of
your visit you're thinking like a fish, a loon, an otter. Other
landscapes provide different input, but the effect is the same.
Unless.
Twenty years and 150 lakes later, Lodge sees the patterns and
timing of invasions and senses another landscape slipping away.
Only now he hopes his science can intervene. Though the pace of
action at the federal level can be frustratingly slow, he believes
a clear consensus is emerging. "Even industries that depend on
the live organism trade are beginning to realize the extent of
the problem," he says.
"In the same way that there is a strong emotional, spiritual
and cultural connection to historical buildings and urban parks,
the plants and animals of the rural and wild landscape, especially
those unique to an area, are very important," says Lodge. "The
beauty, the smell, the changes over the seasons are part of the
connection to family, social traditions and God. Maintaining the
existence of the local and regional flora and fauna is as important
as the preservation of historic buildings. Seeing the Alabama
woods I used to walk in as kid, for example, grown over with kudzu
and Asian honeysuckles, and the lizards I used to catch replaced
by lizards from other countries, is a blow to my identity."
Lodge's dire words continue: "The things we do now will determine
what will happen, or the kind of ecosystems that we'll leave our
children and grandchildren," he says; "Invasion is forever."
* * *
When not fishing the northern lakes by canoe, Erik Ness writes
about science and the environment from his home in Madison, Wisconsin.
(January 2004)
