How adaptive species became invasive

[Guest guest]

From ANIMAL PEOPLE, October 2007:

 

 

How adaptive species became " invasive "

Commentary by Merritt Clifton

 

" Exotic species, " " alien species, " and " invasive species "

are semi-synonymous terms which to most people may seem

insignificantly different.

Each is a metaphor for species not indigenous to their

habitat: non-native species, to introduce yet another term, less

rich in connotation.

Yet obscure as the distinctions among " exotic, " " alien, "

and " invasive " species may be, the terms are different enough to

have inspired environmental advocacy groups and government agencies

to spend millions of dollars in recent years to bring first " alien "

and then " invasive " into vogue.

Behind the linguistic politics is the belief that terminology

tends to shape attitudes. Thus, at about the same time that the

Natural Resources Defense Council began banging the drums about

" invasive " species, In Defense of Animals began to push use of the

term " guardian " rather than " owner " to describe a person who keeps a

pet.

However, while In Defense of Animals sought from the

beginning of the " guardian " campaign to change the language of laws,

the NRDC and others pushing alarm about " invasive " species merely

introduced their preferred terminology into public discourse. The

idea was to increase support for existing policies and programs

against non-native species, not to turn government in a different

direction. Indifferent and often even favorably disposed toward

" exotic " species, the public was believed likely to become more

concerned about " alien " species, and most likely to view " invasive "

species as a threat.

 

What's in a name?

 

Dave Poulson, associate director of the Knight Center for

Environmental Journalism at Michigan State University, maintains an

online glossary of environmental terms. A careful lexicographer,

Poulson recently asked fellow members of the Society of Environmental

Journalists to help him distinguish the differing shades of meaning

among " exotic species, " " alien species, " and " invasive species, "

as used in news coverage.

Doug O'Harra of Far North Science, in Anchorage, Alaska,

offered distinctive definitions which might not withstand all

critical scrutiny, but were accepted by the discussion participants

as accurately reflecting most contemporary newsroom use.

An " exotic species, " O'Harra pronounced, is any species

living somewhere other than where it originated.

An " alien species, " O'Harra opined, is an exotic species

which was deliberately introduced to non-native habitat.

Neither exotic nor alien species " necessarily threaten the

local ecology, " O'Harra stipulated, but an " invasive species " in

his opinion " threatens the ecology of a local habitat by

out-competing or killing off native species--usually because the

native species lack defense mechanisms, " or because the

alien/invasive species no longer faces the predators or parasites

that held it in balance in the species' original habitat. "

This is more-or-less what is usually taught in biology

classes, nature center visitor lectures, and wildlife

documentaries, but as ANIMAL PEOPLE pointed out, O'Harra's summary

misses a key component of the process by which " exotic " or " alien "

species become allegedly " invasive. "

Typically, the ecology of the habitat has already been

transformed by climate change, cultivation, deforestation, drought,

volcanic eruption, or other events that take away the survival

advantages evolved by the native species through natural selection.

Whatever the native species came to do, that helped them in the

habitat of long ago, is no longer advantageous.

For example, shallow-burrowing native marsupials in

Australia lost much of their habitat to the introduction of sheep.

The sheep compacted the soil, ate the native plants, monopolized the

water, and were attended by bored shepherds who often amused

themselves by killing wildlife. The brushy dry forests of

pre-settlement times, burned to make pasture, gave way to desert.

Eurasian rabbits, who evolved with sheep, were enabled to

take over huge swaths of habitat, along with rabbit predators

including feral cats and foxes. Each moved into habitat niches which

had been made more favorable to them than to the extirpated

marsupials.

Thylacenes, of " tasmanian tigers, " also called 'Tasmanian

wolves, " evolved to hunt marsupials in the dry forest. They crashed

toward extinction, and probably would have drastically declined

anyway, even if they had not been persecuted as suspected sheep

predators, because their habitat was radically altered and their

prey base was reduced. Thylacenes had persisted for about 8,000

years in competition with dingoes, who arrived with the first humans

in Australia, but the coming of sheep irrevocably tipped the

balance. Dingo ancestors had hunted rabbits--and sheep--in Asia.

They rapidly made the transition back to a rabbit-based diet, eating

sheep too when they could, and took over the habitat that thylacenes

could no longer hold.

When the adaptive success of " invasive species " to altered

habitat is understood in context, the insidious implications of the

term " invasive " become much more visible.

 

Invasive language

 

The history of the phrase " invasive species " is illustrative

of a linguistic parallel to the evolutionary process of how species

become " invasive, " demonstrating how a misguided belief can wreak

havoc when the cultural climate favors it, no matter how wrong it

is. " Invasive species " is actually of surprisingly recent origin in

common use, and despite years of deliberate effort to introduce it,

it only gained currency when the U.S. " cultural ecology " changed

abruptly in 2001.

Tracing the rise of the " invasive species " issue, ANIMAL PEOPLE ran

keyword searches of 1,428 U.S. newspapers indexed 1976-2006 at

<www.NewsLib-rary.com>. We proportionally weighted the findings to

compensate for the rising frequency with which newspaper content was

filed electronically during the 30-year sampling.

Before 2002, the relatively neutral term " exotic species "

was the most commonly used collective term for non-native animals and

plants. No other term was even commonly used until 1999. The word

" exotic " is most often associated with " different, " " unusual, " or

even " erotic. " The positive associations of " exotic " long frustrated

ecological nativists, whose environmental philosophy evolved in the

19th century parallel to political nativism.

The basic idea behind both strains of nativism is that

whatever existed in a particular place at a specific time chosen by

the power-holders belongs there, while new arrivals are a threat.

Both strains of nativism have waxed and waned repeatedly in

influence, tending to gain strength whenever and wherever the

dominant culture is challenged by immigration.

For example, California in the 1930s could not legally bar

Dustbowl refugees from entering the state, but it could and did set

up checkpoints at the state borders to minutely inspect immigrants

lest they carry produce that might harbor insect pests.

Ecological nativists sought mostly unsuccessfully until

recent years to rally support for eradicating popular animals whom

they perceived as threats to their own favored species, and often

debatably termed " non-native " as a pretext for extermination.

Time and again, nativists were rebuffed--for example, in

seeking to kill mute swans to expand trumpeter swan habitat,

cutthroat trout blamed for depleting native trout in Lake

Yellowstone, and mountain goats who were accused of eating rare

alpine flowers in Olympic National Park.

Nativist purges of hooved species from the Channel Islands

and of feral cats from many locations were waged mostly against

public opinion, and were often possible only when privately funded

organizations such as The Nature Conservancy bought the land to be

purged, then did the killing before turning the land over to the

U.S. or state governments.

The public has generally supported campaigns against the

likes of the lake weed Eurasian watermilfoil, lampreys, zebra

mussels, and gypsy moths, but even these efforts have been stalled

at times by concern rising ever since Rachel Carson published Silent

Spring in 1963 that the chemicals used to kill so-called pests may be

more harmful, in many instances, than the target animals and plants.

For decades wildlife management publications and conferences

have openly and often discussed ways of persuading the public to

share nativist antipathy toward non-native species. Dire warnings

that popular non-native species might displace seldom-seen native

animals and plants have had little or no effect.

Eventually efforts were made to introduce the use of the term

" alien species " in place of " exotic species. " This was slow to catch

on, and for the first decade or more that " alien species " appeared

in print, it was associated mainly with science fiction and teenage

behavior, rather than ecology and biology.

Ecological nativists eventually began trying to introduce the

term " alien species " in place of " exotic species. " This also failed

to kindle. For the first decade or more that " alien species "

appeared in print, it was associated mainly with science fiction and

teenage behavior, rather than ecology and biology.

Only in 1993 did " alien species " gain even marginal

visibility, and the term has never been used by U.S. newspapers at

more than about a third of the frequency of " exotic species. " 1993

also brought an almost fourfold increase in coverage of " illegal

aliens, " and an almost fivefold rise in coverage of " illegal

immigrants. "

Indicative of which non-natives were of most public concern,

" illegal aliens " were mentioned seven times more often in 1993 than

" exotic species " and " alien species " combined. " Illegal immigrants "

were mentioned three and a half times more often.

 

The impact of 9/11

 

Discussion of " invasive species, " not even mentioned in

print before 1988, likewise rose in 1993, reached statistically

significant visibility in 1995, and achieved a virtual dead heat

with " exotic species " by 2001, coincidental with the first external

attack on Americans on American soil since Pearl Harbor, 60 years

before.

Attention to " invasive species " then nearly doubled in one year,

tripled in two years, and by 2006 occurred at four times the

frequency of " exotic species. "

How that happened appears to have little to do with

increasing recognition of an actual problem, as " exotic species " and

" alien species " were discussed no more often than before. Yet

mentions of " illegal aliens " and " illegal immigrants " surged to

five-year highs in 2001, and rose after 2002. Discussion of

" illegal aliens " in 2006 soared to the highest point in a decade,

while discussion of " illegal immigrants " nearly doubled, far

surpassing the 1994 previous peak.

What this means to animals and public policy appears in the

funding allocated by Congress to support the official U.S. government

extermination agency, USDA Wildlife Services--which originally

focused entirely on killing native predators of introduced livestock.

Ancestrally part of the U.S. Geological Survey, funded to extirpate

wolves from the continental U.S. in the early 20th century, this

agency was moved to the U.S. Fish & Wildlife Service, retitled

Animal Damage Control, and assigned to exterminate coyotes in 1930.

Under the Fish & Wildlife Service, coyotes were massacred in

record numbers year after year, yet spread from the southeastern

quadrant of the U.S. to all 48 states plus Alaska. Amid indications

that the Fish & Wildlife Service had become uncomfortable with the

predator control mission, and under pressure from western ranchers

to kill even more coyotes, former U.S. President Ronald Reagan moved

Animal Damage Control to the USDA in 1986. The USDA renamed the

agency Wildlife Services to try to shake the murderous reputation

established by Animal Damage Control, but without success.

Wildlife Services, with a 1998 budget of $28.7 million, was

nearly abolished in June 1998 by the House of Representatives. A

motion by Peter DeFazio (D-Oregon) that would have in effect

disbanded Wildlife Services actually cleared the House on first

reading, strongly supported by pro-animal organizations and some

environmental groups, who recognized the mandate of exterminating

predators as inherently anti-ecological, and especially mistrusted

the use of chemical sprays and poisons. The DeFazio motion,

unfortunately, was defeated on a second vote after frantic rancher

lobbying.

Ecological nativists then joined with ranchers in racheting

up alarm about " invasive species, " managing to nearly triple

coverage during the next year.

At instigation of then-U.S. Vice President Albert Gore,

then-U.S. President Bill Clinton in February 1999 reinforced and

enormously expanded the role of Wildlife Services by creating the

Invasive Species Council, whose continuing existence is reauthorized

by the so-called REPAIR Act passed by the House of Representatives on

October 23, 2007. The main stated goal of the Invasive Species

Council is to eradicate such non-native " nuisance species " as kudzu

weed, gypsy moths, zebra mussels, and fire ants-by hiring Wildlife

Services.

In the fine print, however, the anti- " invasive species "

mandate extends to practically any species hated by anyone

influential.

The strategy of preserving Wildlife Services by aligning it

with the nativist philosophies of many major environmental groups

succeeded bigtime. Under current U.S. President George W. Bush, the

USDA Wildlife Services budget has expanded to $78 million in fiscal

2007, nearly three times the 1998 budget. Since the Bush

administration in 2004 pushed through Congress an amendment to the

1918 Migratory Bird Treaty Act that stripped more than 100 bird

species of protection, Wildlife Services can kill animals with less

restraint than at any time since the 1973 passage of the Endangered

Species Act.

 

Bio-xenophobia

 

And there is no longer much opposition to the killing from

most of the environmental community. Many of the biggest

environmental organizations are now preoccupied with human

immigration issues, ranging from the effects of increased human

population to the question of how fencing the U.S. border with Mexico

may affect jaguars and pronghorn. The Gray Ranch, a Nature

Conservancy property in southern New Mexico, includes routes often

used by illegal immigrants. The Sierra Club has been deeply and

bitterly split by debate over member resolutions, so far not

approved, opposing immigration.

Ecological issues associated with human immigration are real

and must be addressed, not least because they are probably only

beginning. The most recent projections of the effects of global

warming suggest that huge movements of humanity are inevitable, as

result of droughts, floods, fires, rising seas, and possible

famines. The human movements will be only one symptom of

environmental changes that are already starkly evident in the

receding snowcaps on most high mountain ranges, worldwide. Species

evolve in response to habitat, not points identified by a Global

Positioning System, and the habitat that many North American species

prefer is already several hundred miles north of where it was just a

few decades ago.

Climate change and ecological transformation are inevitable,

even if the global warming trend is reversed well short of the

worst-case scenarios. In view of that circumstance, rigidly

defining " native " v.s. " non-native " species is an exercise in

futility, no matter what names are used for them. Nature, not

human intervention, will decide where animals and plants " belong "

and thrive.

Bio-xenophobia looks more and more like just another symptom

of plain old-fashioned xenophobia: the fear of anything exotic or

alien, invasive or not.

 

 

--

Merritt Clifton

Editor, ANIMAL PEOPLE

P.O. Box 960

Clinton, WA 98236

 

Telephone: 360-579-2505

Fax: 360-579-2575

E-mail: anmlpepl

Web: www.animalpeoplenews.org

 

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