Taking Wildness in Hand: Rescuing Species

Photo: Constance Toops

TORREYA STATE PARK perches on the steep, sandy banks of the Apalachicola, where the river twists slowly through the Florida Panhandle toward the Gulf of Mexico. This is one of the most isolated spots in Florida, rich only in plant life and prisons, stupefyingly hot in summer and eerily quiet nearly all year round. Most park visitors are on their way somewhere else, and when Connie Barlow stopped here on a winter day in 1999, she was no exception.

Barlow, trim and now in her fifties, is a writer and naturalist with cropped hair and a childlike air of enthusiasm. She’s given to wandering, and back then she shuttled between a trailer in southern New Mexico and an apartment in New York City. That winter, during a detour to Florida, she paused at the park for a look at its raison d’être — an ancient tree species called Torreya taxifolia, familiarly known as the Florida torreya or, less romantically, stinking cedar. The park lies at the heart of the tree’s tiny range, which stretches little more than twenty miles from the Georgia state line toward the mouth of the Apalachicola. But even at Torreya State Park, Barlow discovered, the Florida torreya is hard to find.

Torreya taxifolia was once a common sight along the Apalachicola, plentiful enough to be cut for Christmas trees, its rot-resistant wood perfect for fence posts. But at some point in the middle of the last century — no one is quite sure when — the trees began to die. Beset by a mysterious disease, overabundant deer, feral hogs, drought, and perhaps a stressful climate, the adult trees were reduced to a handful of mossy trunks, rotting in riverside ravines.

The species persists in Florida as less than a thousand gangly survivors, most only a few feet tall, their trunks no thicker than a child’s wrist, none known to reproduce. Much like the American chestnut, these trees are frozen in preadolescence, knocked back by disease or other adversaries before they grow large enough to set seed. To see their grape-sized seeds, Barlow had to visit the state park offices, where two sit preserved in a jam jar.

Barlow continued her travels that winter but returned to the park a few years later. She tracked down some of the few remaining trees and, in a quiet moment, sat under one of the largest specimens, perhaps ten feet tall. The Florida torreya, even at its healthiest, isn’t an obviously charismatic tree. Its flat needles are scanty; its trunk lacks the grandeur of a redwood or an old-growth fir; when it does manage to produce seeds, the rotting results smell like vomit. In its diminished state, it inspires more pity than awe; to call its spindly limbs a canopy is a sorry joke.

But when Barlow looked up at the branches of the Florida torreya, she made an impulsive commitment to the species. She’d spent years thinking and writing about evolution and ecology, and was aware of the implications of climate change. She decided the species needed to move north, to cooler, less diseased climes. And since it couldn’t move fast enough alone, Barlow would move it herself.

CLIMATE CHANGE IS BEGINNING to make good on its threats, and news of its work is now hard to avoid. Escalating average global temperatures? Check. Rising seas? Check. Plants and animals scampering uphill and toward the poles? Check. Dozens of birds and butterfly species are shifting their ranges to cooler terrain or migrating earlier in the year, each species reacting somewhat differently. Ecological communities, never as stable as we might like to think, are disarticulating in new ways.

Conservationists, in response, have offered more ambitious versions of familiar strategies. Bigger nature reserves. More protected corridors for wildlife migration and movement. More regulations, incentives, and ingenuity in service of greenhouse-gas reductions. But even the most expedient tactics could leave some species — especially those as tightly circumscribed as the Florida torreya — marooned in habitat too hot, dry, wet, or stormy.

What then? Captive breeding without hope of reintroduction is an expensive and indefinite custodial project, an ark with no gangplank. The next option sounds either laughable or desperate: pick up the plants and animals, and carry them to better habitat. Jason McLachlan, an ecologist at the University of Notre Dame, remembers giving a talk in North Carolina about forest responses to climate change. “Someone in the audience said, ‘Why is this a problem? You can just move them,'” he says. “I thought he was just being a smartass.”

It’s an easy idea to caricature. FedEx the polar bears to Antarctica! Airlift the pikas and the orchids! But some scientists take the concept very seriously. Camille Parmesan, a professor at the University of Texas at Austin and an authority on the ecological effects of climate change, remembers broaching the subject at an international conservation conference nearly a decade ago. “I said, ‘Look, we need to start thinking about transplanting organisms around these barriers of agricultural land or urban land, and getting them to the next possible suitable habitat as the climate changes,’ and people were horrified — just horrified,” she says. “They said, ‘You can’t do that!'”

But discussion continued among scientists — if mostly in whispers — and in 2004, a graduate student named Brian Keel quietly coined a term for the idea: assisted migration. Not long afterward, Connie Barlow and the Florida torreya shoved the debate into the open.

THE APALACHICOLA RIVER is bordered by a thick layer of sand, in places more than one hundred feet deep, left when the sea retreated some two million years ago. Rain — which fell generously here, exceeding sixty inches each year, until the recent drought — hits the loose, sandy soil and keeps going, seeping downward until layers of clay and limestone stop its vertical progress. The moisture then turns toward the main stem of the river, each trickle pulling a few grains of sand with it, a sabotage from below known as sapping erosion.

Over millennia, sapping erosion has created nearly sheer-walled ravines known as steepheads, their sandy banks held in place by magnolias, pines, and muscular beeches. Found in only a handful of other spots throughout the world, steepheads and the shady forests they cradle now define this stretch of the Apalachicola. To step from the sunny, logging-scarred Apalachicola uplands into a steephead is to enter a darker, wetter, more complicated world, ignored by chainsaws and seemingly hidden from time.

On a humid fall day near the end of hurricane season, David Printiss leads the way over the edge of a steephead, pointing out the faint, narrow path that hairpins down the wall. A few moments after beginning the descent, he crouches in the leaf litter, then turns with a grin. “Introducing Torreya taxifolia!”

The tree is a bundle of pencil-thin stems, the tallest two feet high, ridiculously small in comparison to the mature trees surrounding it, dwarfed even by a single leaf of a nearby needle palm.

Printiss is the manager of this preserve — The Nature Conservancy Apalachicola Bluffs and Ravines Preserve, just south of Torreya State Park — and he’s proud that the Florida torreya survives in these ravines, even in this almost symbolic state. But he spends most of his time thinking not about the fewer than one hundred Torreya taxifolia on the preserve, but about the landscape surrounding them. Restoring that, he says, is the best way to solve the “Torreya puzzle” and give the tree a chance to thrive.

Printiss has a salt-and-pepper beard, a discreet earring, and a serious demeanor, and he lives here on the preserve with his wife and young daughter. He wears Carhartt work trousers and heavy leather fire boots to the office, and uses both. Each year, he serves as “burn boss” on about twenty prescribed fires, some as large as five hundred acres.

“If I can get fire across the landscape acting in its natural role, I’ve done my job; I’m home,” says Printiss as he drives the soft, sandy roads on the flat preserve uplands. “I’m not saying fire is the answer, but I suspect it’s a large part of the answer.” Restoring fire to the uplands, he says, thins out the overgrown hardwood trees, makes room for the restoration of longleaf pine stands and native grasslands, and brings some filtered sunlight back to the steep ravines where the Florida torreya once grew.

Printiss acknowledges that even if the species were to be revived by these efforts, it could still face the perplexing blight, which attacks the trees by killing the stems and leaving the trees to resprout from their bases. Most surviving Torreya taxifolia, like the one at Printiss’s feet, have withstood multiple onslaughts and are now clusters of genetically identical stems; since the 1960s, only a single tree is known to have set seed. Despite years of study, no researcher has conclusively identified the disease or its source, and some speculate it may even be a suite of diseases.

Since T. taxifolia has separate male and female plants, any trees that managed to persist through adolescence would need the added good fortune of growing near a mate. Only then could the pollen ride the wind to a female tree and produce the species’ distinctively hefty seeds. On top of those difficulties is the Southeast’s record-breaking drought, which shrank water supplies to dangerously low levels last fall, making the oncoming stresses of climate change difficult to ignore.

Yet the suggestion of assisted migration, of planting Torreya taxifolia trees outside these Panhandle steepheads, makes Printiss’s face tighten. Such efforts, he says, threaten to take attention and funding away from the work in the preserve, and make an already bad situation even worse.

“A lot of people just want to let it go up there [in Appalachia] and let it rip,” he says, his voice rising. “They say it’ll act a lot like the northern hemlock, this, that, and the other thing. Yeah, maybe. When it comes to introducing non-native species, we have such overwhelming evidence of good ideas gone bad . . . and this isn’t just the Conservancy’s policy, it’s my personal policy . . . it’s very dangerous tinkering.”

THIS IS THE LONGSTANDING conservation credo: With enough space, money, and knowledge, we can protect natural places and, in many cases, restore them by stitching them back together. But while we’re welcome to restore, redesign is frowned upon; that sort of tinkering crosses an invisible line between humans and capital-N Nature, and risks making things much worse. We’ve good reason to distrust ourselves, after all. Until the 1950s, we thought planting kudzu was a good idea.

But climate change calls all this into question. If rising temperatures and changing weather patterns make restoration difficult or impossible, new brands of meddling may sometimes be the only alternative to extinction. Connie Barlow believes Torreya taxifolia, with its almost absurdly gloomy prospects in its current range, already requires a new strategy — and she welcomes the chance to provide it.

Barlow describes herself as “more interventionist” than many of the scientists and conservationists she encounters, explaining that her background in ecology and evolutionary biology have immersed her in the long time-scales of evolution. “I don’t have a sense of what’s normal,” she says. “I do have a sense of species moving a lot through time.”

Following her first visits to Torreya State Park, Barlow started an e-mail correspondence with botanists, conservationists, and others about the future of the tree. Some, such as paleoecologist Paul Martin, loved the idea of moving T. taxifolia north. The Florida torreya is widely believed to be an ice age relict, “left behind” after the last glacial retreat and very possibly better suited for cooler climates, with or without global warming. So why not return it to the southern Appalachians, where it grew during the Pleistocene? These arguments were countered by an ecologist named Mark Schwartz, who has studied the Florida torreya at the Apalachicola Bluffs preserve since the late 1980s, and remains one of the scant handful of scientists with in-depth knowledge of the species. Schwartz defended the chances for restoration in the species’ present-day range. Before long, the discussion reached an impasse, and the disagreement found an audience.

In a 2004 forum in the now-defunct journal Wild Earth, Barlow and Martin made what might be the first public case for assisted migration. Moving even federally endangered plants like the Florida torreya to more favorable climates, they wrote, was “easy, legal, and cheap,” and Torreya taxifolia, prevented by highways, topography, and its own biology from moving quickly on its own, needed immediate help.

While horticulturists at the Atlanta Botanical Garden have spent years raising Torreya taxifolia in greenhouses and seminatural “potted orchards” in northern Georgia, Barlow and Martin dismissed these efforts, saying that “potted is the botanical equivalent of caged.” They proposed that T. taxifolia be planted on privately owned forest lands in southern Appalachia, easily four hundred miles from the Florida Panhandle. The risk of the slow-growing, problem-prone Florida torreya becoming an invasive weed is vanishingly small, they argued, and in the Appalachian forests, the tree might even take the place of the eastern hemlock, another subcanopy conifer in precipitous decline.

Schwartz, now a professor at the University of California, Davis, responded by acknowledging both the critical situation of the Florida torreya and the possibility of healthier habitat in Appalachia. But he balked at assisted migration for much the same reasons that David Printiss — and many conservationists of all stripes — meet the idea with almost visceral hostility. The Florida torreya is unlikely to become the next kudzu, but the next species on the poleward wagon might very well prove a nasty invasive. And since scientists don’t know precisely what climate change will mean for Torreya taxifolia and other species, conservationists can only make rough predictions about future habitats and future relationships among species. The unknowns are staggering.

If the theory of assisted migration isn’t controversial enough, Schwartz points out, the reality is sure to be even more contentious: while people may be willing to export familiar species to safer habitats, they’re less likely to open their home ecosystems to exotic refugees. “Here in northern California, if we were to ask people whether we can move a salamander that’s going extinct because of climate change into Oregon, people would probably say yes,” Schwartz says. “But if we ask people whether we can introduce a southern California species into a redwood grove for the same reason, they would uniformly say, No way!”

Perhaps the most disturbing implication of assisted migration is that the traditional conservation notion — call it an illusion if you like — of a place to get back to will disappear for good. Yet with or without assisted migration, that pristine place is already slipping out of reach. The demarcation between managed and wild has always been tenuous, defined more by emotion than data, and weakened over decades by the global reach of humankind: acid rain, DDT, PCBs, the traces of Prozac in rivers and streams. Climate change is the most dramatic transgression yet, for its effects range from pole to pole and can’t be fenced in, mopped up, or halted by a National Park Service boundary.

Climate change is altering the wilderness peak, the backyard nature preserve, the wild-and-scenic desert river — all the longstanding conservation victories, the places that not only lend inspiration and solace to the conservation movement, but also prove the wisdom of its tactics. In transforming places once thought protected, in violating hard-fought boundaries, climate change is busting the limits of conservation itself.

THE PASSIONATE CRITICS of assisted migration didn’t stop Connie Barlow, who moved briskly ahead with her plans for the Florida torreya. She created a website called the Torreya Guardians, where she and a handful of amateur horticulturists began to trade information about Torreya taxifolia cultivation in other habitats.

Their vision of the Florida torreya’s future begins in the mountains of north Georgia, where the roads narrow and twist, and travel is measured in time instead of distance. Here Jack Johnston, a sleepy-eyed emergency-room nurse and amateur horticulturist, started growing Florida torreya after meeting Connie Barlow at a dinner in North Carolina. On the steep ground behind his house, on terraces that legend has it were used for growing corn for white lightning in the 1930s, Johnston is cultivating a half-dozen Torreya taxifolia seedlings he bought, legally, from a nursery in South Carolina. Each is about two feet high, five years old, and healthy.

Johnston, whose isolated property is full of other rare plants (“I’m moving all sorts of things north,” he jokes) is pleased by the apparent flexibility of his charges, and nonchalant about the implications of assisted migration. “People have been moving plants around for a long time,” he says. “This idea that we should be territorial about our plants, well, that’s just kind of a provincial attitude.”

The next day, during a long-awaited rainstorm in western North Carolina, Lee Barnes, the de facto lieutenant of the Torreya Guardians, is eager to talk Torreya. “I’m a horticulturist,” he says. “I’m a professional tinkerer.” Barnes, who is no stranger to T. taxifolia — he wrote his doctoral dissertation on the cultivation of the Florida torreya and two other endangered Florida species in the 1980s — has so far collected and distributed about 120 seeds to about a dozen people and gardens north of Georgia, including amateur gardeners in Ohio, New York, England, Switzerland, and elsewhere. Some recipients have reported their successes and failures; some have not.

Barnes’s seed supply comes from a single grove of Torreya taxifolia, which grows not in Florida but about thirty miles from his home in North Carolina. In the 1930s and 1940s, on the grounds of George Vanderbilt’s grand Biltmore Estate, an enterprising head gardener planted seeds he and his botanical accomplices (known as the Azalea Hunters) collected from throughout the Southeast. Today, lines of tourists snake through the vast gardens, but few notice the unassuming, thin-limbed conifers that stand, unmarked, among magnolias, pines, oaks, and redwoods.

Bill Alexander, forest historian for the estate, has lived on these grounds for twenty years, and he walks along the curving path through this cultivated forest, pointing out each Florida torreya in turn. These trees, all apparently free of the disease that scourges the Panhandle populations, were likely planted in the 1930s or 1940s — though perhaps as early as the 1890s — and some graze fifty feet, a height now unimaginable in Florida. Despite freezes and hurricanes, the Florida torreya has done itself proud in North Carolina: one of the trees at Biltmore, Alexander believes, is the second-largest of the species. The largest stands on a farm in northeastern North Carolina, surrounded by rusting farm equipment.

Alexander, who traces his family back to some of the first European settlers in the Biltmore area, is no ecosaboteur, but he likes the democratic, do-it-yourself approach of the Torreya Guardians, and he wants to see the species survive, no matter its longitude and latitude. He says he’ll happily supply seeds to the group as long as the Biltmore trees continue to produce. And if the resulting seedlings establish themselves outside gardens and the manicured grounds of the Biltmore estate? Alexander looks pleased. “Well,” he says, “then I’ll think, ‘By God, we’ve been successful.'”

IN 2007, ecologist Mark Schwartz and two colleagues, Jessica Hellmann and Jason McLachlan, published a paper that modestly proposes a “framework for debate” on assisted migration. While they criticized “maverick, unsupervised translocation efforts,” such as the Torreya Guardians’, for their potential to undermine conservation work and create conflict, they directed their harshest criticism at “the far more ubiquitous ‘business as usual’ scenario that is the current de facto policy.” The three scientists take different stands on the notion of assisted migration. All are cautious, but McLachlan is usually the most skeptical, and Hellmann, a University of Notre Dame ecologist who studies butterflies on the northern end of their range in British Columbia, is the most open to the concept. “It’s incredibly exciting to think that we could come up with a strategy that might help mitigate the impacts of climate change,” she says.

Last fall, to initiate a broader discussion, the three scientists organized a meeting in Davis, California, with other researchers, land managers, environmental groups, and even an environmental ethicist. The Florida torreya isn’t the only species that might benefit from immediate assisted migration. The Quino checkerspot butterfly has blinked out on the southern end of its range, in the Mexican state of Baja California, while the northern end of its range, in Southern California, has been transformed by development. In South Africa and Namibia, rising temperatures on the northern edge of the range of the quiver tree are killing the succulent plants before the species has a chance to shift south.

But assisted migration is in no case a clear solution. Beyond initial concerns about new invasive species and territorial conflicts among conservationists, the meeting in California raised new questions. What if assisted migration is used to justify new habitat destruction? Who decides which species are moved, and who moves them? Isn’t “assisted colonization” a more appropriate name than “assisted migration,” which reminds people of birds on the wing?

Some researchers also worry that continued discussion about the strategy — which most agree is a last resort, likely too expensive and complicated for widespread use — distracts from the more prosaic, immediate duties of conservation and restoration. Brown University ecologist Dov Sax, an invasive-species researcher working on assisted migration, has grander hopes for the conversation. “Conservation has really been built around a static view of the world,” he says. “Given that climate change is going to happen, we need a whole new suite of strategies that could complement the old ones. This could get more people thinking about the other strategies we need.”

DISCUSSIONS OF CLIMATE CHANGE always seem to end with a dreary litany of required sacrifices, uncomfortable changes that will be demanded of the penitent. There is no doubt that stabilizing the climate will require deep, societywide reforms, some of them costly. But as climate change delivers its inconvenient truths, it also asks us to chuck a persistent and not-very-useful notion: the idea that conservation, and by extension restoration, is about gilt-framed landscapes.

Commitment to particular places and their histories has taken conservation a long way. It gives conservationists ground to stand on, in ways that range from the literal to the spiritual to the political. And restoring these beloved places to past states can restart ecological processes still relevant to the present day. But this sort of restoration works only when the climate is more or less stable — when the past supplies a reasonable facsimile of the future. Restoration ecologists remind us that the most effective restoration focuses not on a given point in the past, but on the revival of clogged or absent natural processes. When climate change makes historical analogues irrelevant, it’s these processes that will help species and systems survive in a new world.

Don Falk, an ecologist at the University of Arizona and the first executive director of the Society for Ecological Restoration, argues that assisted migration is simply another way to impersonate the process of dispersal: its adherents intend to transport species from places humans have made uninhabitable, through places humans have made impassable. Despite its undeniable risks, it may not be as radical as it first seems. It may be just another step in the evolution of conservation.

The job is no longer — if it ever was — to fence off surviving shards of landscape or to try to put everything back the way it used to be. Climate change requires conservationists to husband not a fixed image of a place, but instead the fires, floods, and behaviors that create it, in order to help species and natural systems respond to a host of changes we’re only beginning to understand. Assisted migration is certainly not the right strategy for all species — and given its myriad possible pitfalls, it may not be the right choice for any species. Yet the idea of it, and the discussion it provokes, point toward the future.

Mark Schwartz, for his part, still holds out hope for the recovery of the Florida torreya in Florida, for a small but healthy population of trees in the shady steephead ravines. But each time he visits the Panhandle, he says, he sees fewer and fewer Torreya taxifolia.

Michelle Nijhuis’s writing has recently won a Science Journalism Award from the American Association for the Advancement of Science. She lives in rural western Colorado.


  1. Thank you Orion for bringing this topic to the discussion table with a well-rounded mix of viewpoints.

    While slaving away through my early 20’s and beginning conservation career through weedeating reed canarygrass, hacking blackberries,followed by saving the world through watershed restoration and planting trees, I have often come to this question of how all of this will ecologically play out ecologically under longterm climate change.

    In ecological restoration and conservation, we think and plan our projects in long time spans – ie. 20, 50, 100 years out, and well into perpetuitiy. But what about this in the shadow of looming climate change? Are our efforts justified? Just as the author questions the effect and risks of assisted migration, I also wonder how our effort today will be sustained and reflected by the planet’s health and climate in only 50 years. (I almost wrote “vast amount of effort” until I realized that my several years of AmeriCorps and other low-paying field work and grant writing experience was quite personally biased and not reflective of national and global efforts).

    It is clear that our planet is out of balance. Is meddling and trying to engineer our planet’s nature going to restore that balance or just throw it off kilter even moreso. I am relatively quite young, but I witness too many examples of where doing “the right thing” in the past has gone wrong, and this is especially in regards to transplanting species that have now become invasive. I don’t intend to offend any ecologists or planners with this statement, but how are we scientifically going to assure that we don’t contribute to this invasion of weeds through “engineered” efforts such as assisted migration, especially as those other species in, lets say the further north range, also become in peril with climate change and have to compete with our newly transplanted species. Are we going to transplant all species and ecosystems northward or just those currently in peril? How do we know how these species will respond to moving north? Is just re-locating slightly north enough to ensure survival and proliferation of these species? Then, how soon will that new habitat’s climate change, resulting in the same species in trouble again? I only hope is that we conduct more credible research than the Food and Drug Administration with its unofficial philosophy of innocent until proven guilty for drugs.

    I am personally and professionally dedicated to the conservation and preservation of species, but I sadly lose hope in all of this effort in the shadow of global climate change. Climate change is obviously a huge and complex issue. I wish we could just ask the president to push a button and say “stop” (well not this administration!) So, this obviously is not practical. But, we do have a few simplified options to save our earth’s species: 1. stop/slow down climate change; 2. mitigate for climate change (ie. assisted migration, seedbanking, etc); or a combination of both. I wish I had the answers to not only conserving our species, but even moreso, to restoring the balance of this planet and humankind. Is climate change a symptom of our earth out of balance that we can put a bandaid on or is it a reflection that our planet is out of balance?

    Is it realistic to engineer our way into conserving what we have today, or to strive for a new balance in the future and let mother nature sort out who’s in and out? Do we patch bandaids all over the earth and treat these symptoms of imbalance individually one by one, like our average american improving health by taking cholesterol reducing drugs, purchasing bigger belts, drinking diet pop, and eating nonfat soy cheese; or do we slow down, plant a garden, eating fresh vegetables, exercising our muscles and brains, while savoring our palate. The effective approach for healing our planet, just as in healing our planet earth has to be towards holistically restoring balance.

    I have no idea how we accomplish this, but I’d love to hear your comments and replies. Also I do love all earth’s species, with the minor exception of ticks. Thank you for listening to my rant. ~ J.

  2. This is Connie Barlow, the originator of Torreya Guardians mentioned in the article. I have added hotlinks to this Orion article from our http://www.TorreyaGuardians.org website, and to wikipedia entries on “assisted migration”, “Torreya” and “Torreya taxifolia”. The author, Michelle Nijhuis, did a superb job of giving the human side of the controversy.

    Orion readers who’d like to keep up on Torreya Guardians work and action should visit our website. There you will see that a rewilding action to assist the migration of 31 Torreya taxifolia seedlings will take place on private forested land in western North Carolina (near Highlands) on July 30 and 31.

    Also, as webmaster of the site, I try to keep current a page devoted to listing all the news articles on assisted migration and other forms of rewilding. Go to http://www.torreyaguardians.org/assisted-migration.html

    Together for Torreya,
    Connie Barlow

  3. Very interesting article and important ideas. I’ve been thinking along the same lines here in the foothills of the White Mountain National Forest (Maine/NH). As climate change progresses, and it seems to be happening much faster than “they” and I though possible even a short five years ago, I’ve been wondering about our own forests here in northern New England. We are slated to eventually lose our maples and many pine and fir species and who knows what else. I’ve been thinking it might be a good thing to begin planting tree species that might survive in a warmer climate while being able to also survive the current colder (though not as cold as the past, we’re now considered zone 4 and often 5 and we used to be zone 3) winters. I can’t imagine our beautiful forests replete with dead and dying trees and it will take some time for naturally migrating species to grow to the maturity of our current trees. I can understand the concerns, and I share them given the current invasion of species like purple loosestrife in my neck of the woods. However, nothing like human caused climate change has ever happened before, and dramatic efforts may sometimes be required not only to save species but to help ecosystems that can no longer rely on natural migration, selection, and balance due to roads, development, and other human barriers to what nature would do on her own.

  4. Thank you for the balanced, well-written article.

    I live in China now where the first Torreya tree I came across was the Chinese torreya (Torreya grandis). It produces an edible nut (I assume the ‘Stinking Cedar’, or Florida torreya, does not produce an edible nut?). Literally translated as ‘Fragrant Torreya’, the nut is delicious and is a common snack in southern China and especially at festivals.

    Regarding the Florida Torreya, I was wondering if there is any prior documentation of the tree actually being harmful to other species of plant-life.

    Also, is the current problem only climate? Was there possibly an intoduction into the Apalachicola River area of an insect/weed that has caused the fungus suite? I would love to know more about the theories of the tree’s problems.

    Finally, does anyone know if there is any documentation of the Florida Torreya tree being used by Native Americans (weren’t the Seminoles in that area)? Since Torreya is a 19th century name, what was it called before? I know these questions are somewhat off the eco-path, but I’m just curious.

    Let’s wish the best for both the Torreya taxifola in its native habitat and its survival as a species at large.


  5. Comment on June 22 posting by Stacey Duff:

    Stacey made a very helpful posting on the edibility of the Korean species of genus Torreya. There are 3 or 4 species of Torreya in eastern Asia, and 2 in North America. The California Torreya can still easily be found. I have visited 5 different wild groves in Yosemite NP, Sequoia NP, and 3 places in the Coast Range. (See for photo-essays of all these site visits.)

    Cultural documentation lists the native Americans eating the seed of California Torreya. So why is the “Florida” species the only one of the genus that is endangered?

    I suspect any of 3 possible reasons.

    The first is purely physical. “Florida” Torreya is the only Torreya species that does not live in a mountain habitat. My assessment is that, except for peak glacial periods, “Florida” Torreya was, in fact, a mountain species: that it used to live in the Appalachians and simply got stuck in the “pocket reserve” where it waited out the peak glacial period, along with all of our beloved eastern deciduous forest species, along the Apalachicola River of the Florida Panhandle. Thus, it is the only one of the 5 species that has no easy way to quickly migrate to cooler habitat by heading upslope.

    The second and third reasons would have exacerbated the problem of losing contact with its presumed mountain home. Both pertain to the arrival of the first peoples into North America, beginning perhaps 5,000 years after the peak glacial. Because “Florida” Torreya survived the glacial peak in just the Apalachicola pocket reserve, it is possible that local extirpation of small game deprived the tree of the seed dispersers (squirrels, possibly tortoises) essential for helping the tree move north. The third possibility draws from Stacey’s observation: Given the large seed’s attraction as food, and the tree’s extreme endemism within its tiny pocket reserve, perhaps the human arrivals overharvested the seeds.

    For all these reasons, I conclude that the only way to properly attend to the needs of this highly endangered conifer is to ensure that our ecological knowledge of the plant is supplemented with as much deep-time evolutionary knowledge as we can acquire (and imagine).

    Together for Torreya,
    Connie Barlow

  6. Thank you for this well written article. I must admit that I had never heard of assisted migration. It is a very interesting concept and one to keep in mind for the future. I am a professional horticulturist and have been more interested in conservation in the last 10 years of my 35 year long career. We had a Torreya taxifolia growing in Fairchild Tropical Botanic Garden, south of Miami, where I have worked for the past 35 years. It died several years ago, perhaps due to damage during Hurricane Andrew.

    I am intrigued by the concept of assisted migration for saving endangered species. This might be the only answer for some species. I plan on forwarding this article to our conservation team.

  7. A very challenging article … well done.

    We know that global warming has already occurred and that it threatens many species. As greenhouse gas levels continue to rise, further negative change will happen to the world’s ecosystems and its biodiversity. For some species this means certain extinction … highly specialised species such as the Mountain Pygmy Possum in alpine Australia has no where to go … going higher up mountains is not an option because it already lives near the tops. Taking the animal elsewhere is also not an option because it eats a highly specialised Australian diet, not found, say, in the Swiss Alps! Ditto for Polar Bears as they lose ice flows etc in the Arctic … there is no other suitable habitat they can go to (given a bipolar meltdown). Hence, assisted migration in an active sense (relocation) is not a viable option. Islands, isolated National Parks and other ‘fenced’ reserves will become climate traps.

    What we need to do if we are serious about saving species under threat from warming-induced habitat change is to create massive North – South biodiversity corridors that extend the length of whole continents. Such biodiversity migration corridors would have to be big enough to allow the unassisted migration of biodiversity (plants and animals) both north and south of their current ranges in relation to the Equator. We would also need to create new ‘altitude reserves’ where species are free to move, where it is possible, to higher, more suitable altitudes.

    Human development that impedes such free movement will need to be removed (fences, road and rail corridors, settlements etc etc).

    The choice is clear, we must save biodiversity and we must do so by, as far as is now possible, preserving habitat. If habitat is changing slowly enough for species to adapt by moving, then we must allow them to freely move. Actively intervening and relocating species (assisted migration) is the desperate act of a dominant species that is getting every other aspect of its relationship to nature wrong. Given such a sorry history, we are unlikely to get this final band aid act right and the failure will divert much needed time, resources and energy from the main game.

    The main game is now the conservation of planet earth for all species …. including, if Gaia is sufficiently forgiving, us. To have any chance of maintaining ecosystem health we must reduce greenhouse gas emissions to safe levels and allow an endemic sense of place to re-emerge for all species.

  8. Assisted colonization was the topic of a paper by Hoegh-Guldberg et al. in last Friday’s Science. My criticism of the idea is here

  9. Torreya taxifolia has been rewilded! On July 30, 11 crew members of Torreya Guardians and documenters gathered in Waynesville NC to undertake the first rewilding (into purported ancestral native habitat) of this highly endangered conifer. Thirty seedlings were purchased from a nursery in South Carolina, and then assisted in “migrating” into the southern Appalachian Mountains.

    Ten of the seedlings were planted in forest habitat at Corneille Bryan Native Garden (Lake Junaluska, 2600 feet elevation). The remainder were planted beneath full deciduous canopy on private land at 3,400 feet. Visit a photo-essay of this historic conservation action at:


  10. In a recent interview, Professor Terry Root, Stanford University and one of the recipients of the IPCC NOBEL Peace Prize recipients, addressed the issues taken up in your article

    Climate change will cause a mass extinction of plants and animals. That’s what biologist Terry Root argues:
    – We’ll have to prioritize which species we are going to save.

    She was asked “How is climate change affecting the world’s species?”
    – I have analyzed about 1800 different species and found that about 80 percent of them are changing in the direction that you would expect for global warming. There are two major ways in which species are changing. One is that they start doing things at a different time than before, such as breeding or migrating earlier in the year. On average, behavioural changes have moved about five days per decade in the period 1960 to 2000, that is a total of around 20 days!. The other change is that species move geographically to where it is colder; they move toward the poles and they move to higher elevations.

    In response to the question, “Can there be other explanations for their movement?”, she replied:

    “Some have argued that species moved because of habitat destruction, but if that was the case, they wouldn’t all be moving in the same way, toward, for instance, the poles. With elevation it is harder to tell. It might be that species move to higher elevations because human development is at lower altitudes. If I only had data on elevation I couldn’t be drawing the conclusion that I am doing, but because I have the data on migration toward the poles, I think it is pretty safe to say that climate change is the reason.”

    She was asked, “What is the problem? So, plants and animals are moving due to climate change; it seems as if they are adapting to
    According to her, “The problem is that they have to move across fields and cities and roads and other things that we have put in their way. They may not be able to move; in these cases humans will have to help them move or they will become extinct. Unlike humans, most species have a very narrow space in which they can survive.”

    Professor Root believes that we are at the beginning of another mass extinction. Although there have been six mass extinctions so far in the history of the planet, this one will be caused by only one species. If the temperature goes up two degrees Celsius, we will probably lose around 400 000 species, according to her. That is approximately 20 percent of the known species. If the temperature goes up four degrees Celsius, we could lose 50 percent!

    She answered the question, “Is two degrees increase a realistic prospect?” with:

    “Oh hell no! I don’t think we can keep it at two degrees, given what America is doing. Obama is trying to fix the mess but there is simply too much resistance. But maybe if enough states within the U.S. get serious about it, we might be able to.”

    But does it really matter to humans that species become extinct?

    She says that “if we lose predators of pests, or major pollinators, that is something very serious. Something like 80 percent of all crops are pollinated by wild insects such as bees, ants and butterflies, and also birds. We have seen that bees are disappearing. They’re dying from a fungus, because heating causes stress. This affects their immune system and makes them susceptible to sickness. Crops would largely die out.”

    So what can we do?

    “We’ll have to prioritize which species we are going to save. There is no way we can save all – this is not apparently a Noah’s Ark opportunity. But we can build corridors to help animals move, and we can physically relocate plants, and what I am suggesting is so called “triage” — this is a term used by doctors on a battlefield, when there are so many dying and wounded soldiers that the doctors can’t save all of them. They have to make judgments and only work on the ones that they can save within, say, an hour and a half. What I want to do is to find some generalities, something to help us make such judgments.”

    “We have to ask: what species are possible to save? We have to focus our resources. We should also ask: what species do we really need? To answer this question we would answer species that provide materials, such as cotton and trees and important pollinators and predators of pests. Species with many similar relatives might not be as important to save as those that are unique. And we should also pay attention to what people like, tigers for instance and other ‘charismatic megafauna”. If we make judgments, we can save some of the species that are now going extinct. We can build corridors for animals to travel and physically move plants. But we can’t save them all.”

    In other words, “Noah’s Ark” in our time will have to be a very restrictive one!

    She concludes, “I’m sad to say that we’re leaving the next generation with a hell of a planet.”

    Max Jerneck (Lund, Sweden) and Tom R. Burns (Uppsala, Sweden)

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