Giant Cows, Geoengineering and the Lazarus Frog
Could re-creating previously extinct species recreate whole prehistoric ecosystems, and even prevent catastrophic climate change?
There is already something primeval in the sepia landscape of Kempen-Broek. The sun breaks low and slow through a thick mist that shrouds the Dutch countryside and makes shadows of the trees, still bare from a long, dry winter that has clung on well into April. Dark, squat farmhouses and dark, squat horses line up by the train line that cuts south from Eindhoven to the Belgian border.
Many of the farm buildings have "Te koop"—"For sale"— signs hung outside them, others have simply collapsed into disrepair. Small, uncompetitive farms in a border region whose agriculture has been neglected for years have closed and the industry is sliding. Now, assisted by the local government, conservationists want to push it back even further, to a point before human settlement reshaped the ecology; to a state of wildness that would mean not just bringing back the flora and fauna that has disappeared from the area, but that which has disappeared entirely, placing Kempen-Broek, perhaps unwillingly, as a test case for a controversial movement in conservation: de-extinction.
Here, a conservation group called the ARK Foundation is back-breeding extinct “megafauna” in order to reengineer an ecosystem that disappeared centuries ago, stripping away centuries of human action and unwinding its negative impacts. If proven, their argument that reviving prehistoric animals can recreate prehistoric landscapes could have enormous implications beyond conservation — particularly as advances in synthetic biology bring the recreation of extinct species within reach. In Australia, a team is edging ever closer to bringing back a strange — and extinct — frog, insisting that the last few barriers are technical, not biological. As the links between biodiversity, ecosystem decay and global climate change become better understood, using de-extinction to rewind nature and fix the damage done by mankind is a compelling, and no longer far-fetched prospect.
As its ageing farming community sells up or gives up, the ARK Foundation is pulling down the fences and collapsing the ditches used to reclaim the "broek" — the swampland — letting the water table rise and break down the current pine forests, to be replaced by the broad-leaved species that used to shade the wetlands. Wild horses tramp across the swamp. Two hundred hectares of former farmland bordering the village of Stramproy is being returned to its wild state; by the end of the year that should be 800 hectares. Five other areas in Europe have been selected for this process of "rewilding", returning to a state where wild, native herbivores — bison, red deer, ibex, chamois, moose, reindeer, boar and aurochs — roamed in large herds.
"We see nature as the ultimate tool in restoring itself," says Denis Frissen, who is heading ARK's initiative in the region.
The argument — which has been deployed in the reintroduction of wolves and beavers to habitats in Europe and North America — goes that all species fill an ecological niche, playing a specific role in the ecosystem. The grazing of large herbivores maintains open landscapes and wetlands, preserving their fragile biodiversity; predators keep the herds' populations in check, all working in a dynamic equilibrium. Where human action has excised a species from its niche and unbalanced the system, putting it back in should lead to a "trophic cascade", where natural processes resume and realign.
Grey wolves were hunted out of Yellowstone National Park in the 1920s. The result of their removal from the ecosystem — extirpation, in ecological terminology — had been far-reaching. The wolves’ main prey, the elk, thrived. The elk grazed on young aspen trees, which then failed to grow beyond saplings and form the canopy of the forest, changing the chemistry of the soil beneath the forest and removing the habitat of beavers and bison, whose population began to decline.
In 1995, 14 wolves were reintroduced to the park. The following year, another 17 were released. Fifteen years later there are around 100, in nine packs. Their impact on the ecosystem was captured in a 2011 study by William Ripple and Robert Beschta, from Oregon State University, which showed that the northern parts of the park were in the early stages of recovery. The wolves had curtailed elk numbers, young aspen trees were surviving and bison and beaver populations had increased. Their reintroduction, Ripple and Beschta concluded, “may represent a particularly effective approach for passive restoration.”
That is the rationale that Frissen and his colleagues present at ARK, and it would be unremarkable, were it not that the last of one of the main components of the wilderness ecosystem they propose — the aurochs, a giant ancestor to today's domestic cattle — died in the 17th Century in a Polish forest.
It was once an interesting academic question in ecology: what niche did, or could these species fill in degraded ecosystems? But what is happening in Kempen-Broek may give some answers. In this grey, underpopulated part of the Low Countries, Frissen and his colleagues are breeding a herd of something that, while not exactly aurochs, at least look a lot like them.
“Since we were Neanderthals, we have been creating perfect animals.. All of the dog breeds come from one wolf.”—Denis Frissen
By the side of the road, Frissen stops to check on the progress of a 1,000kg bull that, a few hours earlier, had been tranquilised and moved to a new breeding group. It is a big beast, dark brown with horns like electricity pylons, but it is tiny compared to the massive aurochs, which stood six feet at the shoulder.
After three years, the results of the first three generations of breeding under "Project TaurOs" are scattered around the area. Some are huge and dark, others short and pale with wide curving horns. The team have taken the primeval cattle that still roam in semi-domesticated herds in the highlands of Southern Europe and Scotland, and others selected for their bulk and the size and shape of their horns, and brought them together. Frissen estimates it will take around 25 years before they have created a stable population, but through the same mechanisms used to create today's breeds, streamlined for milk and meat production, ARK and its partners are reverse engineering the animal from the traits found in archaeological records.
"Since we were Neanderthals... we have been creating perfect animals," he says. "All of the dog breeds come from one wolf." Reversing this process should, he argues, be possible, although there will be challenges, not least in breeding back in wild behaviour. Reintroduced to parts of Southern Europe, the TaurOs will need to defend themselves from predators and thrive in lean seasons without any human intervention.
"We are engineering," Frissen says. "That's one of the things we have to deal with."
The finished creature will have many, if not most, of the characteristics of its ancient blueprint, but the TaurOs will not, genetically, be aurochs. ARK is "not interested in Jurassic Park," Frissen says.
However, other proponents of so-called "de-extinction" do talk in terms that a decade ago were confined to pulp science fiction. Synthetic biologists are working on techniques that could enable them to recreate extinct species from their DNA records, fostering them in close relatives. Rebuilding the wooly mammoth or the sabre tooth tiger, creating breathing versions of iconic museum pieces, has captured the attention of the mass media and attracts the kind of eccentric funding often lacking at the frontiers of science.
The number of mammoth finds has accelerated in recent year: in part because more people are looking, knowing the value of a good carcass. A well-preserved body, now on display in Yokohama, may have provided undamaged blood cells, and samples have been sent on to Hwang Woo-suk, the disgraced Korean cloning expert.
For researchers, the advances in synthetic biology required to make de-extinction happen opens up a vast and compelling new theatre of scientific endeavour. Whether or not it is possible is a subject of fierce debate, but it seems inevitable, given the momentum, that someone will come close.
If so, what should be done with the result? There is an emotional dimension to de-extinction, a sense that the damage done by mankind can somehow be undone, repaying an ecological debt to the planet. This is especially true for those more recently wiped out — such as the passenger pigeon, once so populous as to blacken the skies of North America, blasted out a dozen at a time by hunters with shotguns until the last bird died in 1914 in captivity.
The impact would be more than sentimental, even transformative. Could extinct species can be used to backfill the niches emptied by human action? In places here the loss of complex forest or plains systems has led to unexpected and uncontrollable consequences, shifting local climatic and hydrological conditions and threatening human populations, what lengths could, or should conservationists go to try to revive them? What if bringing back the mammoth, the passenger pigeon or the aurochs could be used to engineer trophic cascade and repair parts of the planet being made unviable — de-extinction as geoengineering?
It is not an entirely new idea either. In 1989 in Cherskii, in the far north of the Russian Federation, the geophysicist Sergey Zimov began a project, dubbed the “Pleistocene Park”, which proposes the recreation of a 10,000 year old ecosystem dominated by megafauna, including wooly mammoth and wooly rhinocerous. Around the remote Northeast Science Station — whose website lists among its transport facilities a hovercraft, an airplane and a tank — Zimov is still working on recreating the mammoth’s habitat. In a 2005 essay, he argued that the mass extinction, assumed to be due to changes in the climate ten millennia ago, at the beginning of the Holocene period, could in fact have been partly precipitated by the encroachment of humans, whose evolving hunting techniques devastated the herbivore populations. It was those grazing animals that maintained the steppe, and with them gone, the ecosystem collapsed. The park is testing that hypothesis, as far as it can, with large animals, such as the Yakutian wild horse, bison and musk ox. The mammoth, though, remains the ultimate goal.
Zimov’s thinking includes another, altogether more worrying observation. Grasslands are efficient recyclers of water and chemical nutrients — the so-called rate of “geochemical cycling” is higher than any other major ecosystem types. This means that they can sequester a great deal of carbon dioxide. According to Zimov, the amount of carbon stored in the soils of the former Pleistocene plains is greater than that in all of the world’s rainforests. Rising global temperatures, he has warned, could cause this to be released with devastating consequences.
If Zimov is right, bringing back the mammoth ecosystem could mitigate catastrophic climate change.
Of course, this would all be academic, were it not for the momentum building in synthetic biology, which is bringing de-extinction within touching distance.
In March this year, in a laboratory at the University of Newcastle in Australia, a team of synthetic biologists announced that they had managed to create embryos, albeit unstable ones, of Rheobatrachus silus, a strange frog known for swallowing its eggs and giving birth through its mouth.
The biologists on the “Lazarus Project”, led by the University of New South Wales’ Professor Mike Archer, took DNA from the cryo-preserved cells from the extinct gastric brooding frog, collected in the 1970s. Using a technique known as somatic cell nuclear transfer, they used donor eggs from a distant relative, the great barred frog, deactivated the nuclei and replaced them with Rheobatrachus silus nuclei.
Tests, the university announced, show that the dividing cells in the resulting embryos contained the genetic material of the extinct species. None of the embryos survived more than a few days, but at the time Archer hailed it as a breakthrough, activating the dead genetic material.
“We’re increasingly confident that the hurdles ahead are technological and not biological and that we will succeed,” he said.
The Lazarus Project has other Antipodean wildlife in its sights: the Australian thylacine, or Tasmanian tiger; perhaps New Zealand’s giant moa.
While synthetic biology emerges rapidly as a field of study, and de-extinction with it, conservationists are only just starting to grapple with these, and other questions of what it practically means if someone succeeds in bringing long gone species back to life.
As Kent Redford, chairman of the New York-based Wildlife Conservation Society, says: "So much of this conversation is about 'can you return things?' I’m not sure that’s the right question. I think it’s more important to ask should you? Should you try? And that isn’t a science-based question, that’s a value-based question."
“We’re having amateurs enter the ecological field with the enthusiasm of engineers.”—Kent Redford
Ecological systems are beyond complex. The idea that, until humans kick the scales, species sit eternally in predetermined niches is clearly a simplification. Assuming that by dropping an animal population back into its track, balance can then be restored presupposes that the interactions between species are relatively fixed. As in all chaotic systems, the result of any given action is difficult to predict and is often scale invariant — that is, a large stimulus can have a marginal impact, while a small one can have a catastrophic, system-wide impact.
"Things are constantly shifting and changing. It may very well be that once a species is gone, there is no hole there to put it back in," Redford says. "Now that doesn’t mean that it couldn’t find a way to make its own hole, which is what invasive species have done. But in fact it is a dynamic process, and the actors are making things up as they move across the stage."
Concerned that his colleagues were working in "almost complete ignorance" of synthetic biology, Redford helped to convene a conference at Cambridge University in April that brought together biologists and conservationists to discuss the implications of de-extinction. Having assumed that any major interventions in ecosystems would be passed by them, the conservation community now faces an alien discipline invading their habitat.
"We’re having amateurs enter the ecological field with the enthusiasm of engineers," Redford says. Perhaps surprisingly, he is not hostile — seeing in the increasingly public discussions about de-extinction a chance to revive interest in the "largely depressing and depressed field" of conservation.
Others are more so. Professor David Ehrenfeld from the department of ecology, evolution and natural sciences at Rutgers University has spoken publicly on his skepticism about whether ecological engineering through de-extinction is either possible or desirable. While not entirely dismissive of the progress of the science, he warns that several de-extinction efforts have felt a lot like publicity campaigns.
"This whole business of engineering ecosystems is silly, very much the same as genetic engineering, which frankly doesn't work most of the time," he says. "And that's an easier system to deal with. We're talking about systems with tens of thousands or hundreds of thousands of components, or more, in dynamic flux. It doesn't make any sense."
Ehrenfeld says of Project TaurOs: "That's fine. I don't mind that," on the basis that cattle have continued to graze on the Pleistocene plains where the aurochs lived. "That probably works, if they want to introduce a few aurochs to the cattle. They're essentially the same thing, ecologically," he says.
Others, he says, species which were unique, such as the mammoth or passenger pigeon, have far less predictable impacts; their niches may no longer exist, the ecosystems in which they lived altered permanently by invasive species, climate change or deforestation. They could succeed, but in failure the best case is probably that the effort is wasted.
Just because a reintroduction fails to restore an original ecosystem, it may still have an impact, one which could be far-reaching — the impact of introducing the cane toad to Australia remains a powerful disincentive for any kind of ecological engineering, or should. As with its related discipline, geoengineering, jacking complex natural systems, even in an attempt to repair them, could create new hazards.
With the economic value of ecosystem services now being calculated, what is to stop a company or country working on the science of de-extinction's logical extension — If a plant or animal is needed to fill an apparent niche, why not build one exactly that shape? That is the direction of travel in the genetic modification of crops, so why not animals? Control is always likely to cause concern. As if to highlight the increasing accessibility of these techniques, a California-based company launched the first ever Kickstarter project seeking funds for a synthetic biology venture.
Whatever idealists might believe, it is also, Ehrenfeld notes dryly, unlikely that anything created that then proved valuable would be used pro bono for the public good.
"I think that if anybody did bring back a mammoth, they would probably patent the damn thing," he says. "And then what?"
