Secret: Serious restorationists use herbicides. Sometimes the scale or perniciousness of an alien-invasive problem defeats every other method. Yellow star thistle, a demonic weed, is enveloping the American West the way kudzu blanketed the South; it covers 15 million acres in California alone. Inedible and impassible for wildlife and livestock, it also drives out other plants. The Nature Conservancy uses herbicides such as Milestone, Tordon, and Transline against yellow star thistle in places like Hell’s Canyon, Idaho. Invasive cheatgrass and medusahead have made the West so flammable (a danger that climate change is exacerbating), that the Bureau of Land Management is planning to spray a million acres with a herbicide called Plateau. High Country News reported: “Many environmentalists fear collateral damage. The biologists and land managers on the front lines, however, seem nearly unanimous in saying that the threat posed by weeds outweighs that from herbicides.”
In the national park where I uproot jubata grass, there are some remote stands so thick that I and other volunteers can’t make a dent; Park Service work crews blast those plants with herbicide. Restoring native grassland is customarily done by nuking whole pastures with herbicide and then starting over with native seed. At the river property where I’m restoring upland habitat, I occasionally use glyphosate against a dozen species of invader.
Secret: Heroic clearing of a dense patch of invasive plants is worse than useless. The disturbed ground just invites the same weeds back, or some new ones. The right solution is the Bradley method of regeneration, named for Eileen and Joan Bradley, who invented it in Sydney in the 1960s. Specialists ridiculed their technique until it was tested and then adopted by Australia’s National Trust in 1975; it has spread virally ever since. The sisters’ strategy is to let the native plants do most of the work against the aliens. You start where there are fewest invaders, uprooting them gently, and you take out every kind of weedy exotic, lest they replace each other. Go away for a season and let that set of natives grow strong and aggressive. Next season, help the natives advance further on the main body of invaders with some more gradualist weeding. After a few years of sporadic minimal work, the problem is solved permanently. The sisters’ posthumous book, Bringing Back the Bush (2002), is worth tracking down.
Secret: Alien invasives increase biodiversity. New Zealand is a famously invaded place: It has 2,065 native plants, but 2,069 alien plants have taken up residence. Brown University ecologist Dov Sax points out that New Zealand’s biodiversity has doubled, at a cost of just 3 documented plant extinctions. “I hate the ‘exotics are evil’ bit,” Sax told the New York Times, “because it’s so unscientific.” Extinctions are caused by alien predators, he argues, seldom by alien competitors. According to an article in Permaculture Activist, “Out of a total flora of approximately 6,000 vascular plant species, California has more than 1,000 naturalized exotics; yet fewer than 30 natives are known to have become extinct.”
Secret: Some alien invasives are good or become good. “It’s hard to imagine the American landscape,” wrote Michael Pollan in Second Nature (1991), “without St.-John’s-wort, daisies, dandelions, crabgrass, timothy, clover, pigweed, lamb’s-quarters, buttercup, mullein, Queen Anne’s lace, plantain, or yarrow, but not one of these species grew here before the Puritans landed.” The picturesque golden hills of summer in California are a European artifact: Annual grasses brought by the Spanish largely replaced the native perennial bunchgrasses, whose deep roots kept them somewhat green throughout the year. The new grasses spread so rapidly that by the time the Spanish got to northern California, the oat grass they had introduced in the south had preceded them, and the Indians were already eating the oats. An article in Bay Nature contends that “the Mediterranean annual grasses are . . . now as much a part of California’s grasslands as the native perennial grasses once were. The time is long overdue for an official naturalization ceremony.”
Consider the much-loathed zebra mussel. A classic invader via ballast water, it came from the Black Sea to one of America’s Great Lakes in 1985. By 1996 it had taken over all the Great Lakes and most of the rivers of the Midwest, including the Mississippi. Zebra mussels fasten to hard surfaces in such density that they sink buoys, clog water intakes, coat ships, and suffocate other shellfish; they are a monumental hassle. But Dov Sax (him again), writing with his former teacher, ecologist James Brown, wants us to know:There are two sides to the story. Eutrophication has plagued the Great Lakes for decades. But by filtering phytoplankton and other suspended material from the water column, the non-native zebra mussel has helped clean up Lake Erie and other parts of the Great Lakes, the Hudson River, and many more aquatic environments. These mussels are much more efficient at filtration than their native counterparts. Many birds feed on them, and the mussels’ excrement provides habitat for a food chain anchoring a great diversity of species. Biologists credit the zebra mussel with restoring native grasses and fishes. Were it native, the zebra mussel would be hailed as a savior, not reviled as a scourge.
Secret: Alien invasives aren’t a problem in the tropics. “Those fancy exotics don’t make it over the garden wall,” Daniel Janzen told me. “It really is a jungle out there.” That’s true only on continents, of course. Replete with empty niches, tropical islands are extremely vulnerable to invasion. Australia is the biggest of such islands.
Secret: Climate change favors weeds. Endemic species are often highly specialized to local conditions, with limited range. When conditions change, they are the first to go and are replaced by the feisty, talented travelers we know as weeds. Defending most endangered species at ground level is doomed to fail as the climate shifts. Also, global warming leads to more fires, and the successional growth following a fire is likely to be different than before.
Secret: Biocontrol usually works. Yes indeed, the mongooses that were introduced in Hawaii in 1833 to kill rats ate everything else instead and became an ecological cautionary tale, along with the infamous cane toads imported to Australia in 1935 to control cane beetles. The toad has turned into a nightmare invasive, overrunning the country, eating everything it’s not supposed to, poisoning every creature that tries to eat it—crocodiles, snakes, dingoes, quolls (marsupial cats), and pet dogs. Bash one with a cricket bat and poison sprays into your mouth. But neither mongooses nor cane toads went through the kind of evaluation process now required for biocontrol agents, all of which are insects or smaller because they can be selected for close specificity to the target organism. Three kinds of weevil and two kinds of fly are being used with considerable success by The Nature Conservancy in Hells Canyon in their campaign against yellow star thistle. In the last hundred years, 350 biocontrol agents have been deployed effectively against 133 species of weed, with just 8 cases of a non-target species being harmed—and then never seriously. The California Invasive Plant Council’s newsletter declares, “The ideal biological control agent works year after year, spreading throughout the range of the targeted invasive plant, finding the most hard-to-reach plants. . . . It keeps on working long after we have forgotten that we ever had a problem.”
Prediction: Restorationists will welcome genetically engineered biocontrol. The world’s mitten crabs and comb jellies and fire ants and snake-heads and Nile perch and brown tree snakes and gorse and knapweed and water hyacinth and kudzu are just too damaging and impossible to contain with present techniques. Biocontrol organisms genetically engineered for extreme specificity to the target species are the obvious solution. It’s already happening. At Australia’s Commonwealth Scientific and Industrial Research Organization, in a project that has been under way since 2002, virologist Jackie Pallister is engineering a ranavirus genome to undo the cane toad mistake. It works better than cricket bats.
“Ecology needs to be a predictive science,” Edward O. Wilson told me. At present, ecology is still limited to being an observational science because the observation isn’t complete yet. Some 1.6 to 1.9 million species—no one knows the exact number—have been identified since Carl Linnaeus founded
taxonomy in 1735. Estimates of how many species there are in the world range from 3 million to 100 million (not including the microbes). In other words, we’re so ignorant, we don’t know how ignorant we are.
Gardeners know all the relevant species in their garden; they keep things simple so they can. If we’re going to garden the wild (and the world) responsibly, simplifying is not an option; we have to inventory all of life in order to really understand food webs, energy webs, biogeochemical cycles, seasonal and climatic changes, shifting population ratios: the full gamut of how life works. “Imagine doing chemistry knowing only one-third of the periodic table,” says Terry Gosliner, a mollusc expert at the California Academy of Sciences.
I learned all this because in 2000 I got involved with a scheme we called the All Species Inventory. It was Kevin Kelly’s idea. In a founding statement, he wrote: “If we discovered life on another planet, the first thing we would do is conduct a systematic inventory of that planet’s life. This is something we have never done on our home planet. The aim of the All Species Inventory is simple: within the span of our own generation, record and genetically sample every living species of life on Earth.” My wife, Ryan Phelan, had just sold a company, so we put some money into gathering the world’s leading taxonomists and systematists in San Francisco for a meeting to decide whether a push to identify all life was useful and feasible. Ed Wilson hosted a follow-on meeting at Harvard a few weeks later. The universal message from the scientists was to go for it.
As the project took shape, I got to participate in species inventories in Costa Rica, in the Great Smoky Mountains National Park, and inside a wood rat. (Why inside a wood rat? As with the human microbiome project, we are learning the degree to which life lives on life. Carl Zimmer wrote in Parasite Rex [2000]: “There’s a parrot in Mexico with thirty different species of mites on its feathers alone. And the parasites themselves have parasites, and some of those parasites have parasites of their own. . . . According to one estimate, parasites may outnumber free-living species four to one. In other words, the study of life is, for the most part, parasitology.”) One of the scientists donated $1 million to All Species, but little further funding came, and our organization faded by 2004, although several allied operations have prospered.
• Ed Wilson wrote a much-read 2003 paper for Trends in Ecology and Evolution titled “The Encyclopedia of Life.” The goal, he said, is to “put all the information that we get on species already known into a single great database, an electronic encyclopedia, with a page that’s indefinitely extensible for each species in turn, and that would be available to anybody, any time, anywhere, single access, on command, free.” In 2007 the MacArthur Foundation, the Sloan Foundation, and other sources funded the project, and it partnered with heavyweights—the Smithsonian, the Field Museum, Harvard, Woods Hole, the Missouri Botanical Garden, and the Biodiversity Heritage Library, which is busy digitizing 500 million pages of papers on species to blend in to the encyclopedia. The hope is that by 2017 almost all of the 1.7 million or so known species will be in the database. This will be, Daniel Janzen declared, “the window on the biodiversity of the world, for the world, by the world.”
That “by the world” part is what’s revolutionary. Taxonomy, like the rest of science and academia, is turning upside down. The power has shifted from sequestering data to sharing data. A taxonomist used to build a career by taking ownership of a particular twig of the tree of life—some genus of beetles, say—and then controlling all information about that twig. If you discovered what you thought might be a new species in that genus, you sent your specimen to the specialist and then waited months for a verdict. The revolution started by GenBank changed all that. Because it was the freely accessible online repository of all genetic data, including the human genome, scientists were rewarded for posting half-baked data on GenBank immediately upon discovery. The data would be fully baked in public, through comment and revision and linking, into something usable, available to all. Science broke into a sprint that has accelerated ever since. Old sequesterers who couldn’t adapt retreated into tenured irrelevance.
Enter the next stage, again with Dan Janzen in the thick of it: the Barcode of Life. Janzen had been growling for years that all he wanted was a handheld device. “You find a bug, you rip a leg off it, you put it in the thing, the thing connects to the Internet, and it tells you what the bug is. If it doesn’t know, it assumes you’ve found a new species and asks you details about it, and requests that you also insert a piece of the leaf you found the bug on.” (That last bit shifts the subject from taxonomy to ecology, from identity to relationship.)
In 2003 Paul Hebert, at the University of Guelph in Ontario, developed the beginnings of the shortcut Janzen was seeking. Hebert discovered the diagnostic value of a mitochondrial gene that most animals have—because it is crucial for energy—and that is highly variable because it evolves quickly. The telltale gene fragment is only 648 base pairs long. That means it can be sequenced for $10 a specimen, and that changes the world.
By 2008 the DNA barcoders had analyzed 375,000 specimens. The earliest tests came from Dan Janzen and Winnie Hallwachs in Costa Rica, full of news. One species of skipper butterfly turned out to be 10 different species. As Janzen proceeded to barcode the 10,000 or so butterfly species in the Guanacaste, he discovered that “a standard result is that 20 morphologically-defined species turn into 60 barcode species! A spin-off is that all the generalists disappear: they turn out to be clusters of look-alike specialists.” Brian Fisher at the California Academy of Sciences is barcoding all the ants in Madagascar. A project is under way to barcode the world’s birds, and there’s a campaign to get all the fish barcoded. Now that two diagnostic gene fragments for plant identification have been identified, barcoding of the world’s plants is proceeding. The barcodes, as they emerge, are, of course, being posted on GenBank.
So what?
Well, you just acquired some very subversive power, similar to what you can do with a cellphone camera. Janzen’s handheld DNA device isn’t here quite yet, but in the meantime, you can ship bits of tissue to Guelph for a few bucks and learn amazing things, like whether you’ve been cheated at the fish market. Jesse Ausubel (the Green nuke lover) unleashed two teenage students on ten groceries and four restaurants in Manhattan, collecting fish samples for barcoding. According to the New York Times: They found that one-fourth of the fish samples with identifiable DNA were mislabeled. A piece of sushi sold as the luxury treat white tuna turned out to be Mozambique tilapia, a much cheaper fish that is often raised by farming. Roe supposedly from flying fish was actually from smelt. Seven of nine samples that were called red snapper were mislabeled, and they turned out to be anything from Atlantic cod to Acadian redfish, an endangered species. . . . Two of the 4 restaurants and 6 of the 10 grocery stores had sold mislabeled fish.
Just as pocket calculators democratized math, DNA barcoding makes the whole world bioliterate. As Janzen says, “We can make it so that each of all 7 billion people can know what bit of biodiversity is biting them, appealing to them, worrying them, attracting them, itching them, sickening them, and providing whatever goods or services can come from being able to know what it is.” Amateur bird-watchers transformed ornithology; now empowered with barcoding (and whatever follows it), amateur taxonomists of every stripe will transform our knowledge of life on Earth. All species may be identified. Ecology may become predictive after all.
Ethnobotanist Gary Nabhan tells of an epiphany he had while comparing two maps. One showed the U.S. counties that had the most endangered species. The other displayed counties in terms of the length of people’s residency. The pattern jumped out at him: “Where human populations had stayed in the same place for the greatest duration, fewer plants and animals had become endangered species; in parts of the country where massive in-migrations and exoduses were taking place, more had become endangered.” Another correlation, explored in Nabhan’s Cultures of Habitat (1997), is that, worldwide, regions of high natur
al diversity have high cultural diversity. Life is richest where culture is richest and most constant.
Can that be a goal, a strategy? The way to play Indian is not with feathers, but with attention. You don’t have to be born in a place to be native to it, you just have to engage it long enough and deep enough to belong there. When that happens, you’re well and truly home. The poet Gary Snyder has dwelled since 1970 in a hand-built house in the west-facing foothills of the Sierra Nevada range in California. His e-mails end with his address:Kitkitdizze
north of the South Yuba River
near the headwaters of Blind Shady Creek
in the trees at the high end of a bunchgrass meadow
(Kitkitdizze is the Miwok Indian name for a pine understory shrub found around his place. Perhaps because it is sticky and sharp-smelling, its English name is mountain misery.)
Reinhabitation, we used to call it; also bioregionalism. In CoEvolution and elsewhere we published a reinhabitory quiz meant to put people on the spot about their natural-systems ignorance and inspire greater immersion in their locale. You can find a current version online under the title “The Big Here.” All the versions begin with the injunction, “Point north.” (Can you? Right now?) Then: What phase is the moon in? What local spring wildflower is consistently the first to bloom? Name five native edible plants nearby, and their best season. Name five local birds and say which are migratory. What indigenous tribe used to live where you live now? Is the soil under your feet more clay, sand, rock, or silt? (I fail that one.)
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