Eight Little Piggies (4 page)

The attempted solution, like the horse ingested to catch the fly, created greater havoc than the original problem. Biological control is a good idea in principle—better a natural predator than a chemical poison. But predators, particularly when introduced from alien places and ecosystems, may engender greater problems than the creature that inspired their introduction. How can you know that the new predator will eat only your problem animal? Suppose it prefers other creatures that are benign or useful? Suppose, in particular, that it attacks endemic species (often so vulnerable for lack of evolved defenses in the absence of native predators)?

Biological control should therefore be attempted only with the utmost caution. But, speaking of folk songs and citing a more recent composition than the old lady and the fly, “When will they ever learn?” In my personal pantheon of animals to hate and fear, no creature ranks higher than
Euglandina
, the “killer” or “cannibal” snail of Florida.
Euglandina
eats other snails—with utmost efficiency and voraciousness. It senses slime trails, locks onto them, and follows the path to a quarry then quickly devoured.

Euglandina
has therefore developed a worldwide reputation as a potential agent of biological control for other snails. Yet, despite a few equivocal successes, most attempts have failed, often with disastrous and unintended side-effects, as
Euglandina
leaves the intended enemy alone and turns its attention to a harmless victim.

Forgive my prejudices, but I know what
Euglandina
can do in the most personal way (biologists can get quite emotional about the subjects of their own research). I spent the first big chunk of my career, including my Ph.D. dissertation, working on a remarkable Bermudian land snail named
Poecilozonites
. (This Darwin’s finch among mollusks is the only large land snail that reached Bermuda. It radiated into a score of species in a great range of sizes and shapes. The fossil record is particularly rich, but at least three species survived and were thriving in Bermuda when I began my research in 1963.)
Euglandina
had been introduced in 1958 to control
Otala
, an imported edible snail that escaped from a garden and spread throughout the island as an agricultural pest (same story as
Achatina
and
Partula
on Moorea). I don’t think that
Euglandina
has even dented
Otala
, but it devastated the native
Poecilozonites
. I used to find them by thousands throughout the island. When I returned in 1973 to locate some populations for a student who wanted to investigate their genetics, I could not find a single animal alive. (Last year, I relocated one species, the smallest and most cryptic, but the large
Poecilozonites bermudensis
, major subject of my research, is probably extinct.)

Thus, I feel the pain of Jim Murray, Bryan Clarke, and Mike Johnson. They had published papers on Moorean
Partula
since the mid-1960s. They never expected that their last pair of articles would be a wake.

Euglandina
was introduced to Moorea on March 16, 1977, with the official advice and approval of the
Service de l’Economie Rurale
and the
Division de Recherche Agronomique
—despite easily available knowledge of its failures and devastations elsewhere.
^*
Euglandina
ignored
Achatina
and began a blitzkrieg, against
Partula
—more thorough, rapid, and efficient than anything that Hitler’s armies ever accomplished. When my colleagues wrote their first article about this disaster in 1984 (see bibliography),
Euglandina
had already wiped out one of the seven
Partula
species on Moorea, and was spreading across the island at a rate of 1.2 km per year. Moorea is about 12 km across at the widest, and you quickly run out of island at that rate. My colleagues made the grim prediction that
Partula
would be completely gone by 1986.

One hates to be right about certain things. In 1988, Jim, Bryan, and Mike published another note with a brief and final title: “The extinction of
Partula
on Moorea.”
Partula
is gone. My colleagues managed to collect six of the seven species before the end, and they have established captive breeding programs in zoos and biological research stations in several nations. Perhaps, one day,
Partula
can be reintroduced into Moorea. But
Euglandina
must be eliminated first, and no one knows how this can be done. Deep grafts, whether physical or emotional, are hard to extirpate—as Mary Martin discovered in her unsuccessful attempt to wash that man right out of her hair. Hope remains in Pandora’s box, but how do you reenclose the bad guys?

Moorea may be the Bali Ha’i of our dreams, but life for
Partula
has become an unenchanted evening. Now night has fallen.

The story would be sad enough if only Moorea (and Bermuda) had fallen victim. But
Euglandina
is spreading just as rapidly on the larger, adjacent Tahiti, and
Partula
now survives in only two valleys. The even more diverse
Achatinella
is gone (or nearly so) on Oahu, largely for the same reason, although the spread of Honolulu hasn’t helped either. More than half the species of bulimulids are extinct on the Galápagos.

It is so hard for an evolutionary biologist to write about extinctions caused by human stupidity. Emotions well up and extinguish rationality and writing. What can be said that hasn’t been stated before—with great eloquence and little effect. Even the good arguments have become clichés—as corny as Kansas in August, as normal as blueberry pie.

Let me then float an unconventional plea, the inverse of the usual argument. Inverses often have a salutary effect in reopening pathways of thought. An undergraduate friend during my year in England, a brilliant debater, had to argue the affirmative in that tired old cliché of a subject: “This house believes that the monarchy should be eliminated.” Instead of trotting out the usual points about the queen’s expense account and the negative symbol of royalty in a democratic age, my friend claimed that the monarchy should be eliminated because it is unfair to monarchs and their families. All possibility of a normal private life evaporates. You can’t have a date, drink a beer, or, God forbid, even belch in public without a headline in next day’s scandal sheet.

The extinction of
Partula
is unfair to
Partula
. This is the conventional argument, and I do not challenge its primacy. But we need a humanistic ecology as well, both for the practical reason that people will always touch people more than snails do or can, and for the moral reason that humans are legitimately the measure of all ethical questions—for these are our issues, not nature’s.

So I say, let us grieve for Henry Edward Crampton when we consider
Partula
on Moorea—for
Euglandina
and human stupidity have destroyed his lifetime’s dedication. Crampton visited the Pacific a dozen times, when transportation was no aerial picnic. He tramped up and down the valleys, over the dangerous precipices, in intense tropical heat. He spent months and months measuring snails and toting up columns of figures
sans
computer—the worst sort of scientific drudgery. He published three great monographs on
Partula
.

The work is of great and permanent value in itself. But Crampton did not write for personal glory or to establish the frozen evolutionary moment of his own studies. He labored all his life to provide a baseline for future evolutionary work.
Partula
was a natural evolutionary laboratory, and he toiled to establish a starting point, with utmost care and precision, so that others could move the work forward and continue to learn about evolution by tracing the future history of
Partula
. What is more noble than a man’s intellectual dedication—a lifetime of perseverance through the Scylla and Charybdis of all field biology: occasional danger and prolonged tedium? Crampton’s work is now undone, even mocked. Grieve for his lost and lofty purposes.

Yet I also appreciate that we cannot win this battle to save species and environments without forging an emotional bond between ourselves and nature as well—for we will not fight to save what we do not love (but only appreciate in some abstract sense). So let them all continue—the films, the books, the television programs, the zoos, the little half acre of ecological preserve in any community, the primary school lessons, the museum demonstrations, even (though you will never find me there) the 6:00
A.M.
bird walks.

Let them continue and expand because we must have visceral contact in order to love. We really must make room for nature in our hearts. Consider one last image of Ezio Pinza as Emil De Becque in
South Pacific
, and accept the traditional characterization of nature as female (if this convention offends you, then make nature male and fall “in love with a wonderful guy”). The words may be banal (and Pinza was only extolling Mary Martin, while I speak of all nature), but the emotional setting is incomparable and still can bring tears to any unjaded eye. Think of this greatest of bassos as he soars up to the tonic of his chord:

PATIENCE ENJOYS
a long pedigree of favor. Chaucer pronounced it “an heigh vertu, certeyn” (“The Franklin’s Tale”), while the New Testament had already made a motto of the Old Testament’s most famous embodiment: “Ye have heard of the patience of Job” (James 5:11). Yet some cases seem so extended in diligence and time that another factor beyond sheer endurance must lie behind the wait. When Alberich, having lost the Ring of the Niebelungen fully three operas ago, shows up in Act 2 of
Götterdämmerung
to advise his son Hagen on strategies for recovery, we can hardly suppress a flicker of admiration for this otherwise unlovable character. (I happen to adore Wagner, but I do recognize that a wait through nearly all of the Ring cycle would be, to certain unenlightened folks, the very definition of eternity in Hades.)

Patience of this magnitude usually involves a deep understanding of a fundamental principle, central to my own profession of geology but all too rarely grasped in daily life—the effects of scale. Phenomena unfold on their own appropriate scales of space and time and may be invisible in our myopic world of dimensions assessed by comparison with human height and times metered by human lifespans. So much of accumulating importance at earthly scales—the results of geological erosion, evolutionary changes in lineages—is invisible by the measuring rod of a human life. So much that matters to particles in the microscopic world of molecules—the history of a dust grain subject to Brownian motion, the fate of shrunken people in
Fantastic Voyage
or
Inner
Space—either averages out to stability at our scale or simply stands below our limits of perception.

It takes a particular kind of genius or deep understanding to transcend this most pervasive of all conceptual biases and to capture a phenomenon by grasping a proper scale beyond the measuring rods of our own world. Alberich and Wotan know that pursuit of the Ring is dynastic or generational, not personal. William of Baskerville (in Umberto Eco’s Name
of the Rose
) solves his medieval mystery because he alone understands that, in the perspective of centuries, the convulsive events of his own day (the dispute between papacies of Rome and Avignon) will be forgotten, while the only surviving copy of a book by Aristotle may influence millennia. Architects of medieval cathedrals had to frame satisfaction on scales beyond their own existence, for they could not live to witness the completion of their designs.

May I indulge in a personal anecdote on the subject of scale? I loved to memorize facts as a child, but rebelled at those I deemed unimportant (baseball stats were in, popes of Rome and kings of England out). In sixth grade, I had to memorize the sequence of land acquisitions that built America. I could see the rationale behind learning the Louisiana Purchase and the Mexican Cession, for they added big chunks to our totality. But I remember balking, and publicly challenging the long-suffering Ms. Stack, at the Gadsden Purchase of 1853. Why did I have to know about a sliver of southern Arizona and New Mexico?

Now I am finally hoist on my own petard (blown up by my own noxious charge according to the etymologies). After a lifetime of complete nonimpact by the Gadsden Purchase, I have become unwittingly embroiled in a controversy about a tiny bit of territory within this smallest of American growing points. A little bit of a little bit—so much for effects of scale and the penalties of blithe ignorance.

The case is a classic example of a genre (environmentalists vs. developers) made familiar in recent struggles to save endangered populations—the snail darter of a few years back, the northern spotted owl vs. timber interests. The University of Arizona, with the backing of an international consortium of astronomers, wishes to build a complex of telescopes atop Mount Graham in southeastern Arizona (part of the Gadsden Purchase). But the old-growth spruce-fir habitat on the mountaintop provides the central range for
Tamiasciurus hudsonicus grahamensis
, the Mount Graham Red Squirrel—a distinctive subspecies that lives nowhere else, and that forms the southernmost population of the entire species. The population has already been reduced to some one hundred survivors, and destruction of 125 acres of spruce-fir growth (to build the telescopes) within the 700 or so remaining acres of best habitat might well administer a coup de grâce to this fragile population.

I cannot state an expert opinion on details of this controversy (I have already confessed my ignorance about everything involving the Gadsden Purchase and its legacy). Many questions need to be answered. Is the population already too small to survive in any case? If not, could the population, with proper management, coexist with the telescopes in the remaining habitat?

I do not think that, practically or morally, we can defend a policy of saving every distinctive local population of organisms. I can cite a good rationale for the preservation of species, for each species is a unique and separate natural object that, once lost, can never be reconstituted. But subspecies are distinctive local populations of species with broader geographical ranges. Subspecies are dynamic, interbreedable, and constantly changing; what then are we saving by declaring them all inviolate? Thus, I confess that I do not agree with all arguments advanced by defenders of the Mount Graham Red Squirrel. One leaflet, for example, argues: “The population has been recently shown to have a fixed, homozygous allele which is unique in Western North America.” Sorry folks. I will stoutly defend species, but we cannot ask for the preservation of every distinctive gene, unless we find a way to abolish death itself (for many organisms carry unique mutations).

No, I think that for local populations of species with broader ranges, the brief for preservation must be made on a case by case basis, not on a general principle of preservation (lest the environmental movement ultimately lose popular support for trying to freeze a dynamic evolutionary world in
statu
quo). On this proper basis of individual merit, I am entirely persuaded that the Mount Graham Red Squirrel should be protected, for two reasons.

First, the squirrel itself: The Mount Graham Red is an unusually interesting local population within an important species. It is isolated from all other populations and forms the southernmost extreme of the species’s range. Such peripheral populations, living in marginal habitats, are of special interest to students of evolution.

Second, the habitat: Environmentalists continually face the political reality that support and funding can be won for soft, cuddly, and “attractive” animals, but not for slimy, grubby, and ugly creatures (of potentially greater evolutionary interest and practical significance) or for habitats. This situation had led to the practical concept of “umbrella” or “indicator” species—surrogates for a larger ecological entity worthy of preservation. Thus, the giant panda (really quite a boring and ornery creature despite its good looks) raises money to save the remaining bamboo forests of China (and a plethora of other endangered creatures with no political clout); the northern spotted owl has just rescued some magnificent stands of old-growth giant cedars, Douglas fir, and redwoods (and I say Hosanna); and the Mount Graham Red Squirrel may save a rare and precious habitat of extraordinary evolutionary interest.

The Pinaleno Mountains, reaching 10,720 feet at Mount Graham, are an isolated fault block range separated from others by alluvial and desert valleys that dip to less than 3,000 feet in elevation. The high peaks of the Pinalenos contain an important and unusual fauna for two reasons. First, they harbor a junction of two biogeographic provinces: the Nearctic or northern by way of the Colorado Plateau and the Neotropical or southern via the Mexican Plateau. The Mount Graham Red Squirrel (a northern species) can live this far south because high elevations reproduce the climate and habitat found nearer sea level in the more congenial north. Second, and more important to evolutionists, the old-growth spruce-fir habitats on the high peaks of the Pinalenos are isolated “sky islands”—10,000-year-old remnants of a habitat more widely spread over the region of the Gadsden Purchase during the height of the last ice age. In evolutionary terms, these isolated pieces of habitat are true islands—patches of more northern microclimate surrounded by southern desert. They are functionally equivalent to bits of land in the ocean. Consider the role that islands (like the Galapagos) have played both in developing the concepts of evolutionary theory and in acting as cradles of origin (through isolation) or vestiges of preservation for biological novelties.

Thus, whether or not the telescopes will drive the Mount Graham Red Squirrel to extinction (an unsettled question well outside my area of expertise), the sky islands of the Pinalenos are precious habitats that should not be compromised. Let the Mount Graham Red Squirrel, so worthy of preservation in its own right, also serve as an indicator species for the unique and fragile habitat that it occupies.

But why should I, a confirmed eastern urbanite who has already disclaimed all concern for the Gadsden Purchase, choose to involve myself in the case of the Mount Graham Red Squirrel? The answer, unsurprisingly, is that I have been enlisted—involuntarily and on the wrong side to boot. I am fighting mad, and fighting back.

The June 7, 1990,
Wall Street Journal
ran a pro-development, anti-squirrel opinion piece by Michael D. Copeland (identified as “executive director of the Political Economy Research Center in Bozeman, Montana”) under the patently absurd title: “No Red Squirrels? Mother Nature May Be Better Off.” (I can at least grasp, while still rejecting, the claim that nature would be no worse off if the squirrels died, but I am utterly befuddled at how anyone could devise an argument that the squirrels inflict a positive harm upon the mother of us all!) In any case, Mr. Copeland misunderstood my writings in formulating a supposedly scientific argument for his position.

Now scarcely a day goes by when I do not read a misrepresentation of my views (usually by creationists, racists, or football fans in order of frequency). My response to nearly all misquotation is the effective retort of preference: utter silence. (Honorable intellectual disagreement should always be addressed; misquotation should be ignored, when possible and politically practical). I make an exception in this case because Copeland cited me in the service of a classic false argument—the standard, almost canonical misuse of my profession of paleontology in debates about extinction. We have been enlisted again and again, in opposition to our actual opinions and in support of attitudes that most of us regard as anathema, to uphold arguments by developers about the irrelevance (or even, in this case, the benevolence) of modern anthropogenic extinction. This standard error is a classic example of failure to understand the importance of scale—and thus I return to the premise and structure of my introductory paragraphs (did you really think that I waffled on so long about scale only so I could talk about the Gadsden Purchase?).

Paleontologists do discuss the inevitability of extinction for all species—in the long run, and on the broad scale of geological time. We are fond of saying that 99 percent or more of all species that ever lived are now extinct. (My colleague Dave Raup often opens talks on extinction with a zinging one-liner: “To a first approximation, all species are extinct.”) We do therefore identify extinction as the normal fate of species. We also talk a lot—more of late since new data have made the field so exciting—about mass extinctions that punctuate the history of life from time to time. We do discuss the issue of eventual “recovery” from the effects of these extinctions, in the sense that life does rebuild or surpass its former diversity several million years after a great dying. Finally, we do allow that mass extinctions break up stable faunas and, in this sense, permit or even foster evolutionary innovations well down the road (including the dominance of mammals and the eventual origin of humans, following the death of dinosaurs).

From these statements about extinction in the fullness of geological time (on scales of millions of years), some apologists for development have argued that extinction at any scale (even of local populations within years or decades) poses no biological worry but, on the contrary, must be viewed as a comfortable part of an inevitable natural order. Or so Copeland states:

From these facts, largely irrelevant to red squirrels on Mount Graham, Copeland makes inferences about the benevolence of extinction in general (though the argument only aplies to geological scales):

But all will “disappear over time, regardless of our efforts”—millions of years from now for most species if we don’t interfere. The mean lifespan of marine invertebrate species lies between 5 and 10 million years; terrestrial vertebrate species turn over more rapidly, but still average in the low millions. By contrast, Homo
sapiens
may be only 200,000 years old or so and may enjoy a considerable future if we don’t self-destruct. Similarly, recovery from mass extinction takes its natural measure in millions of years—as much as 10 million or more for fully rekindled diversity after major catastrophic events.