Friday, January 15, 2016

DNA sequencing reveals the fate of Ötzi the Iceman

Today in Scientific Reports, researchers from the European Academy of Bolzano/Bozen (EURAC) have reported on the fate, and ultimate extinction, of Ötzi the Iceman’s maternal genetic lineage. With these new insights the fates of both Ötzi’s maternal and paternal genomes have been conclusively revealed.

Ever since Ötzi’s body was discovered in 1991, scientists have sought to understand not only who he was and how he lived, but also where he lay within Europe’s genetic history. Although the sequence of Otzi’s mitochondrial genome was published in 2008, and his nuclear genomic sequence was reported in 2012, several questions remained unanswered.

The Iceman. Image source: © EURAC/Marion Lafogler

When Ötzi’s mitochondrial genome was sequenced in 2008, scientists showed that it belonged to the relatively broad K1 mitochondrial genetic lineage. More specifically, Ötzi’s maternal genetic lineage was referred to as K1f. The authors had compared the Iceman’s mitochondrial genomic sequence to modern samples, hoping to identify any traces of the K1f mitochondrial lineage within the modern population. However, a relatively limited set of modern samples hampered their ability to conclusively uncover Ötzi’s maternal genomic signature within the modern humans of today. Traces of the K1f lineage could have been absent from the samples in 2008, either because the sample size was too small, or because the K1f genetic line had gone extinct.

According to Valentina Coia, first author of this most recent study “The first hypothesis could not be ruled out given that the study considered only 85 modern comparison samples from the K1 lineage – the genetic lineage that also includes that of Ötzi – which comprised few samples from Europe and especially none from the eastern Alps, which are home to populations that presumably have a genetic continuity with the Iceman. To test the two hypotheses, we needed to compare Ötzi’s mitochondrial DNA with a larger number of modern samples.”

“To test the two hypotheses, we needed to compare Ötzi’s mitochondrial DNA with a larger number of modern samples.”

In order to confirm the extinction of Ötzi’s maternal genetic line, Coia and her colleagues examined the DNA of 1,077 individuals including members of Ötzi’s broader K1 lineage, as well as individuals descending from similar genetic lineages. Despite the relatively large set of samples studied, the research teams were unable to uncover evidence of the Iceman’s K1f maternal genetic lineage, or even genetically close lineages, within the modern population.

Though Ötzi’s maternal genetic lineage appears to be extinct, his descendants live on. In 2013, DNA testing of blood samples taken from the Tyrol region of Austria identified 19 men that appear to be genetic descendants of Ötzi. Publishing today in Scientific Reports, Coia and her colleagues further pursued exploring the history of Ötzi’s paternal genetic line, which endures within Europe today. By comparing DNA results from their modern samples, as well as genetic samples taken from 14 different European archaeological sites, the researchers have developed a working hypothesis for the ultimate fates of Ötzi’s maternal and paternal genomes. The researchers believe that members of Ötzi’s paternal lineage arrived in Europe from the Near East approximately 8,000 years ago. At some point following this migration, they believe that Ötzi’s paternal lineage was replaced in most of Europe, remaining only in isolated regions including Sardinia. In contrast to the relatively geographically diverse members of Ötzi’s paternal lineage, Coia and her colleagues suggest that members of Ötzi’s maternal line were a relatively small population remaining geographically isolated and stationary. Ultimately, the authors believe that the same migrations that displaced the Iceman’s paternal ancestors in much of Europe ultimately displaced, and rendered extinct, Ötzi’s maternal line.

Teresa-Lynn Martin | Meta Science Fellow

Featured image: South Tyrol Museum of Archaeology/EURAC/M.Lafogler
This story was prepared with materials provided by the European Academy of Bolzano/Bozen (EURAC).


Dog domestication increased harmful genetic changes

Domesticating dogs from gray wolves more than 15,000 years ago involved artificial selection and inbreeding, but the effects of these processes on dog genomes have been little-studied.

UCLA researchers analyzed the complete genome sequences of 19 wolves; 25 wild dogs from 10 different countries; and 46 domesticated dogs from 34 different breeds. They found that domestication may have led to a rise in the number of harmful genetic changes in dogs, likely as a result of temporary reductions in population size known as bottlenecks.

Various dog breeds (stock image).
Credit: © ots-photo / Fotolia

"Population bottlenecks tied to domestication, rather than recent inbreeding, likely led to an increased frequency of deleterious genetic variations in dogs," said Kirk Lohmueller, senior author of the research and assistant professor of ecology and evolutionary biology in the UCLA College.

"Our research suggests that such variants may have piggybacked onto positively selected regions, which were also enriched in disease-related genes," Lohmueller said. "Thus, the use of small populations artificially bred for desired traits, such as smaller body size or coat color, may have led to an accumulation of harmful genetic variations in dogs."

Such variations, Lohmueller said, could potentially lead to a number of different developmental disorders and other health risks.

Selective breeding programs, particularly those aimed at conserving rare and endangered species, may need to include and maintain large populations to minimize the inadvertent enrichment of harmful genetic changes, he said.

The research was published recently in the journal Proceedings of the National Academy of Sciences. The lead authors are Clare Marsden, a UCLA assistant project scientist in Lohmueller's research group, and Diego Ortega-Del Vecchyo, a UCLA graduate student in Lohmueller's research group; co-authors include Robert Wayne, a professor of ecology and evolutionary biology in the UCLA College.

In 2014, Lohmueller was named a 2014 Searle Scholar for his innovative research; he was also awarded a Sloan Research Fellowship by the Alfred P. Sloan Foundation.


Why crows hold funerals for their dead

Crows are known to gather together around other dead crows but the behavior was a mystery, until now. (Photo: John C Evans/Shutterstock)

There's an unusual but known behavior among crows, that they gather around the bodies of their dead. A crow dead on the street or in a field will be surrounded by a few to a dozen or more crows, all seeming to contemplate their fallen comrade. The notion of crow funerals has been documented but not necessarily understood, so University of Washington biologists Kaeli Swift and John Marzluff decided to create experiments to find out what exactly is happening.

Wednesday, January 13, 2016

Why Earth's Largest Ape Went Extinct

A depiction of Gigantopithecus blacki, the largest ape to ever walk the Earth.
Credit: Wikimedia Commons

The biggest primate that ever walked the Earth may have died out because of its giant size and limited diet, new research suggests.

Little is known about the mysterious Gigantopithecus blacki, a distant relative to orangutans that stood up to 10 feet (3 meters) tall and weighed up to 595 lbs. (270 kilograms).

However, a new analysis of its diet suggests it lived and ate exclusively in the forest. When its forest habitats shrank about 100,000 years ago, the enormous ape may not have been able to snag enough food to survive and reproduce, and went extinct as a result, said study co-author Hervé Bocherens, a paleontologist at the University of Tübingen in Germany. [6 Extinct Animals That Could Be Brought Back to Life]

"Dragon teeth"
Scientists know almost nothing about the mysterious ape. The first hint of its existence came in 1935, when German paleontologist Gustav von Koenigswald happened upon Gigantopithecus molars in a pharmacy in China; the molars were labeled as "dragon teeth," which practitioners of traditional Chinese medicine believe can heal a variety of maladies.

For years, that was the only trace of the greatest ape that ever lived. Since then, however, researchers have found dozens of teeth and a few partial jaws of Gigantopithecus in several spots in southern China, Vietnam and even India.

"There is no skull, no postcranial skeleton. Everything is very mysterious," Bocherens told Live Science.

Based on fossils, researchers believe G. blacki roamed throughout Southeast Asia for at least 1 million years, going extinct around 100,000 years ago. Its morphology suggests its closest living relatives areorangutans, meaning that African primates such as chimps are more closely related to humans than to G. blacki, he said. [In Photos: A Game-Changing Primate Discovery]

Overgrown pandas?
Scientists still knew relatively little about how the gigantic beast lived and why it died out, though theories abound. Noting the similarity between the large size of G. blacki's molars and the overgrown chompers of giant pandas, some have argued G. blacki dined exclusively on bamboo. But wear and tear on the teeth of G. blacki suggested it ate a diet heavy on fruits, with leaves and roots in the mix, Bocherens said.

To get a better picture, Bocherens and his colleagues conducted a chemical analysis of a Gigantopithecus blacki tooth first uncovered in a cave in Thailand near a dam teeming with other fossils, including remnants of orangutans, deer, buffalo and porcupine. (The dam has since been completed and the site has washed away, Bocherens said.)

Because grasses and leafy plants use slightly different chemical pathways for photosynthesis, grasses accumulate higher levels of carbon-13 (meaning carbon with seven neutrons) than carbon-12 (which has six neutrons). As animals up the food chain eat these plants, they retain the chemical signature of their diet in the ratio of these carbon isotopes present in their bones and teeth. As a result, the scientists were able to identify the diet and habitat of G. blacki based on the ratio ofcarbon isotopes in its tooth enamel. The team also analyzed the dietary signature of the other large mammals found at the Thailand site, as well as the diets of existing large mammals.

Doomed to extinction
It turned out that G. blacki ate, and presumably lived, exclusively in forested regions. But the carbon ratios in the other animals from the cave revealed they were eating a mix of foods from both the savanna and the forest. That suggests that at the time the gigantic ape lived, Southeast Asia was a mosaic of forest and savanna. So Gigantopithecus blacki lived near huge swaths of grassland, yet didn't forage in the nearby grasslands.

The combination of this restricted diet and its huge size may have doomed the giant creatures, Bocherens said.

"Living in the forest was really the only option for Gigantopithecus. So if the forest disappears, there is no possibility to find another habitat," Bocherens said.

It's likely that each time the climate got cooler and drier at various points in the Pleistocene epoch, the forested region shrank and the population of G. blacki crashed. Sometime around 100,000 years ago, a cold snap occurred and there were simply too few of the giant beasts left to survive, the researchers speculate.

As supporting evidence for this hypothesis, Bocherens notes that similar "population bottlenecks" reduced the range of orangutans from almost all of Southeast Asia to their current tiny habitats in the rainforests of Sumatra and Borneo. However, orangutans have smaller bodies and can reduce their metabolism to very low levels during seasons when fruit is unavailable, which likely helped keep their population stable during periods when forest habitat was sparse. Gigantopithecus may not have had that option.

Still, the story doesn't completely explain why G. blacki disappeared when it did, Bocherens said.

"There were a lot of fluctuations of climate, and there were also colder and drier conditions." Bocherens said. "I see this as a beginning study. It's putting a new piece in the puzzle, and the puzzle is not very complete."

Monday, January 11, 2016

Wolves found to be better at problem-solving task than domesticated dogs

Credit: Noël Zia Lee, Wikimedia Commons

(—Monique Udell, a researcher with Oregon State University, has found via experimentation, that domestic dogs appear to have lost some of their problem solving abilities as a result of their long history with humans. In her paper published in the journal Biology Letters, she describes a study she carried out and offers some theories on why she believe domesticated dogs may have lost some of their natural skills.
Udell notes that dogs have long been known to work with people as they go about their lives, in contrast to animals in the wild—one such striking behavior is their tendency to look back at their human companion when faced with a perplexing situation—seemingly asking for help. To learn more about this behavior, Udell enlisted the assistance of ten dogs that live as pets (and their owners), ten that live in shelters, and ten wolves that have been raised by humans.

Each of the animals was presented with a tasty sausage, which they were allowed to sniff, but not eat. Instead, the sausage was placed inside of a plastic container with a snap-on lid connected to a short length of rope. To open the container, the animals needed to pull on the rope while holding down the container—a task Udell deemed relatively easy for animals as smart as dogs and wolves. Udell conducted the experiments in two ways, one where the animal was left alone with the container, the other where there was a human (their owners) standing close by.

Udell reports that none of the pet dogs was able to open the container and just one of the shelter dogs was able to do so, but eight of the ten wolves succeeded. The presence of a person nearby didn't help much, the same number of wolves succeeded and one pet did so. She notes that all of the dogs from both groups spent a lot more of their time looking at the person, than did the wolves. Next, Udell allowed a human to offer encouragement to the dogs—doing so increased the success rate of the shelter dogs, four of them opened the container, but still just one pet dog was able to do it.

The experiment is intriguing Udell notes, because all of the dogs and wolves were capable of opening the container, but only the wolves were truly motivated to do so, as demonstrated by a much higher level of persistence—the dogs on the other hand appeared much more ready to ask for help.

More information: When dogs look back: inhibition of independent problem-solving behaviour in domestic dogs (Canis lupus familiaris) compared with wolves (Canis lupus), Biology Letters, Published 16 September 2015.DOI: 10.1098/rsbl.2015.0489

Domestic dogs have been recognized for their social sensitivity and aptitude in human-guided tasks. For example, prior studies have demonstrated that dogs look to humans when confronted with an unsolvable task; an action often interpreted as soliciting necessary help. Conversely, wolves persist on such tasks. While dogs' 'looking back' behaviour has been used as an example of socio-cognitive advancement, an alternative explanation is that pet dogs show less persistence on independent tasks more generally. In this study, pet dogs, shelter dogs and wolves were given up to three opportunities to open a solvable puzzle box: when subjects were with a neutral human caretaker, alone and when encouraged by the human. Wolves were more persistent and more successful on this task than dogs, with 80% average success rate for wolves versus a 5% average success rate for dogs in both the human-in and alone conditions. Dogs showed increased contact with the puzzle box during the encouragement condition, but only a moderate increase in problem-solving success. Social sensitivity appears to play an important role in pet and shelter dogs' willingness to engage in problem-solving behaviour, which could suggest generalized dependence on, or deference to, human action.


Sunday, January 10, 2016

Tuesday, January 5, 2016

Safe Passage

Illustration by Mike Reagan.

on a soggy September afternoon in southeast British Columbia, Nancy Newhouse swung her truck through a bank of pearl-colored fog and bounced to a halt on the shoulder of Highway 3A. Newhouse, Tom Swann, and I emerged into the cold mist, stepping carefully around the puddled ruts carved in the pullout. A convoy of logging trucks, their beds heavy with timber, sprayed mud at our shins. Adjusting our raingear, we began trudging north along the highway; to our left, a screen of cedar, spruce, and Doug fir shielded the valley below. After a hundred yards, the curtain thinned, and Newhouse stopped.

“There it is,” she said, the hood of her Nature Conservancy of Canada raincoat pulled low over her eyes. She pointed through the trees, toward the floor of the Creston Valley. “There’s the corridor.” I followed her finger, baffled. Sorry, I wanted to ask, but where’s the corridor? I searched in vain for signage. A non- descript swath of grainfields glimmered through the shifting fog. The land lay flat, furrowed with oats. The brown arm of a dike, built to stave off the floodwaters of nearby Duck Lake, wormed across the property.
Though the land appeared mundane to my human eye—Yellowstone it wasn’t—from a grizzly bear’s standpoint you’d be hard-pressed to find a more important parcel in North America. This humble polygon of farmland, dubbed the Frog Bear Conservation Corridor, was a crucial piece in a two- thousand-mile puzzle, a bridge that would allow isolated clusters of Ursus arctos horribilis to mingle and mate. “This movement corridor is well known,” Swann, Newhouse’s colleague at Nature Conservancy of Canada, told me as raindrops pooled in his trim white beard. “The science is clear.” That science was why NCC had recently purchased and protected 679 acres of the Creston Valley. Though the land’s $2.5 million price tag was steep, Newhouse and Swann had help: over half the funds had come from the Yellowstone to Yukon Conservation Initiative, one of the world’s most ambitious wildlife groups.

The vision of Yellowstone to Yukon, or Y2Y, is jaw-dropping: Its leaders espouse a continentwide network of protected areas and corridors that would allow animals to wander unhindered through a landscape the size of France, Spain, and the United Kingdom combined. The organization’s advocates dream that the effort will preserve migration routes for caribou and wolves, link pockets of far-ranging creatures like wolverines, and help animals of all sizes flee northward in the face of climate change. The group’s totem, however, is the grizzly, whose expansive habitat requirements make it a useful umbrella for protecting other species. If an ecosystem can support bears, it’s probably healthy enough for everything else.
The acquisition of those 679 acres represents the apotheosis of Y2Y’s approach to conservation, in which habitat connectivity reigns supreme. For a century, environmentalists focused on protecting scenic places—the peaks and ridges that define, say, Glacier National Park—at the expense of valley bottoms, the fertile areas we’ve commandeered for crops and towns. John Muir wouldn’t have been much impressed by the Creston Valley. “Why would you preserve flat grainfields when they’re not biologically rich at all?” Harvey Locke, Y2Y’s founder, asked me later. “Only if you understand that they’re absolutely essential to the functioning of the landscape.”

Just as Frog Bear isn’t classically beautiful, neither is it remote: the town of Creston lies just a few miles south. As it turns out, grizzlies and humans share similar taste in habitat. For wildlife, the valleys that we’ve colonized are natural travel corridors, each feeding into the next, sewing landscapes together. The frontlines in the battle to reconnect North America fall at these fragile margins, the delicate interfaces where wild ecosystems and human settlements collide. The key to conservation, as practiced by Y2Y, is to unplug the bottlenecks created by civilization. Thinking big is good, but thinking smart is better.
“Amazing, isn’t it,” said Swann, gazing out over the gray meadows. “You protect all that land, and it comes down tothis.

ON THE MORNING of June 6, 1998, a sandy-haired Canadian named Karsten Heuer heaved a backpack bulging with snowshoes, ice axes, and fuel canisters onto his shoulders. He wore blue cargo pants and brown boots crisp from their packaging. As the sun climbed the Montana sky, he stepped onto a trail near the northern border of Yellowstone National Park and began to walk.

Heuer, then twenty-nine, had spent the last few years in Banff National Park, working as a ranger and tracking wildlife. But he had grander dreams. In 1993, he’d attended a presentation by an environmental lawyer from Calgary named Harvey Locke. Locke, then thirty-four, had just returned from a horseback trip through the Canadian Rockies, where he’d seen caribou, moose, and a parade of grizzly tracks. The abundance of large mammals heartened Locke, who, like many environmentalists, was coming to realize that North America’s protected areas were too small and scattered to sustain wildlife. A bombshell 1987 study in Nature had revealed that parks were hemorrhaging fauna: lynx had vanished from Mount Rainier, otter from Crater Lake, red fox from Bryce Canyon. Wildlife needed more room to find food and breed than most parks afforded; the smaller the park, the fewer animals it could support, and the greater the risk of extinction—after all, five moose are more likely to disappear than five hundred. Too many populations were isolated from immigrants that could bolster their numbers, and animals that ventured beyond park boundaries too often fell victim to cars and guns. Conservation’s leading lights believed that conjoining the continent’s fragmented wildlands was the only way to stave off collapse.
One evening during his trip, Locke had been seized by the connectivity zeitgeist. He’d crouched by a campfire and, in the margins of a topo map, scribbled the first lines of an essay espousing a chain of wildlife corridors throughout the Northern Rockies, from the Arctic Circle to Wyoming. Locke retreated into his tent and wrote through the night; by the time he’d emerged, he’d scrawled the words “Yellowstone to Yukon” for the first time. The response was ecstatic. Since the discipline’s founding, conservation biologists had functioned as an army of Dutch boys, desperately attempting to plug biodiversity’s leaky dikes, losing as many species as they saved. But Y2Y was different: proactive, bold, an antidote to despondency.

When Heuer first heard Locke’s vision, though, he was skeptical. He brimmed with questions: Would locals support the scheme? Was there habitat left to connect? Finally, he proposed a 2,200-mile hike: part ground-truthing exercise, part publicity stunt. Y2Y had captured imaginations, but no one knew if it could work. Heuer aimed to find out.
Starting from that Yellowstone trailhead, Heuer and a rotating cast of companions hiked, skied, and canoed through three states, two provinces, and one territory over eighteen months. Along the way, he was caught in an avalanche, stood his ground against a charging black bear, and gained as much elevation as summiting Mount Everest twenty times. Once a week, he threw on an oxford shirt and ducked into trailside towns to give talks and interviews. Timber and mining companies planted a stream of negative press before him; the day he arrived in Prince George, British Columbia, the newspaper blared, “80,000 jobs to be lost due to Y2Y.” Coal company flacks heckled him at his lectures. His sister-cum-publicist received a death threat. When Y2Y wasn’t being assailed by industry, it was mocked by Aaron Sorkin. In 1999, the TV show The West Wing parodied Y2Y as the “Wolves Only Roadway,” the vanity project of humorless tree-huggers. After the greenies aver that the roadway would cost $900 million, they get laughed out of the White House.

IN SEPTEMBER 2013—fifteen years after the first footfall of Heuer’s hike, and twenty since Harvey Locke coined his phrase—a companion and I set out to see how Y2Y’s lofty vision was faring. Our trip was considerably less heroic than Heuer’s, as many of our predecessor’s experiences—dangling off an icy cornice, skis kicking wildly at thin air—were not ones we were eager to recreate. Instead of by hiking boots and snowshoes, we were transported by a 2002 Camry with a well-stickered bumper. The closest we came to peril were some perturbing check-engine lights.

In a way, though, our civilized mode of travel was fitting. To be sure, Y2Y’s anchors are still wildernesses like British Columbia’s Muskwa-Kechika, a remote biodiversity stronghold the size of Ireland. In 1993, just 12 percent of the acres within Y2Y’s borders were preserved; today, 21 percent are parks, and another 31 percent have other protections. That’s classic conservation: secure the wild stuff. During our 2013 tour, we’d see few of those places. Attempting to visit the Muskwa-Kechika by car would be like trying to survey the Mariana Trench from a kayak.

Increasingly, however, Y2Y’s battles are fought not in the backcountry, but in the boardroom. Locke’s preposterous idea now commands eleven full-time staffers, a $2.5 million operating budget, and over 200 partners—land trusts, activists, and scientists whose local activities are compatible with the larger vision of continentwide connectivity. Y2Y is effectively a relay race, in which each region is trying to hand off an intact landscape to the next: Yellowstone to the High Divide, the Waterton Front to the Canadian Rockies, Jasper to the Muskwa-Kechika. In 2013, Karsten Heuer became Y2Y’s president, the coach responsible for coordinating the race’s runners.

Heuer is a scruffily bearded man with a square, sturdy frame that looks well suited to a backpack. When I met him at Y2Y’s headquarters in Canmore, Alberta, he still seemed surprised he’d taken the job. He and his wife, the filmmaker Leanne Allison, had long maintained a half-feral lifestyle: They’d migrated alongside caribou above the Arctic Circle in 2003; in 2007, they rambled three thousand miles with their two-year-old son in homage to the writer Farley Mowat. But their peregrinations were now on hiatus, backburnered by fundraising and strategic planning from a second-story office above a bank and a Starbucks.
“I just got back from three days of meetings in East Glacier,” Heuer said as we sat down. He wore a rumpled plaid shirt; his voice was husky with a lingering cold. “One of the most spectacular landscapes in the world, amazing weather, and we were hunkered down in a basement with no windows. My every molecule was yearning to be outside.” Sometimes, when he travels for conferences, he brings a tent. As we talked, he sketched maps of watersheds on scrap paper, almost unconsciously, as though the Rockies had infiltrated the recesses of his brain.

Though Heuer was then only forty-two, he had applied for the job in deference to his own mortality: as he put it, “How was I going to make as much change as possible happen before I die?” To see why change was necessary, we needed simply to look out the window onto Canmore, a former mining community reborn as a tourism paradise. The town lies at the floor of the Bow Valley; beyond its borders loom the sharp peaks of Banff National Park. The layout fairly epitomizes traditional “rock and ice” conservation: abandon the steep slopes to wildlife, claim the hospitable flatlands for humans. For decades, any critter that ventured down from the mountains was greeted with a bullet.

As trigger-happy miners ceded to animal-loving outdoorsmen, though, wildlife began traversing the village again. Collateral damage ensued: cougars devoured pets; a child was nipped by a coyote; a grizzly killed a jogger. “We’ve encroached on an important corridor for feeding, breeding, and movement,” Kim Titchener, then-president of a local group called BearSafety, told me. “This place is a smorgasbord of crazy conflicts.”

To alleviate clashes, Canmore has designated several wildlife corridors—flat swaths of land, several hundred meters wide, that circumnavigate the town. Preventing those pathways from being clogged by condos and golf courses has required constant vigilance; just before I arrived in Canmore, a developer had temporarily scrapped plans for a new megaresort, in part due to Y2Y’s campaigning. Though years of surveying have demonstrated that wolves, bears, cougars, and elk indeed frequent the corridors, animals don’t always stick to precedent. “You’ll read in the literature that grizzlies need a half-kilometer of buffer, and then you’ll hear about one on somebody’s porch,” one ecologist told me with a rueful grin. Even the eminent biologist Bill Newmark, author of the 1987 Naturestudy that helped catalyze Yellowstone to Yukon, doubted that wildlife would comply with Y2Y’s best-laid plans. “It’s a corridor in people’s minds,” Newmark opined in 2009. “Whether or not animals really use it is another question.”

Who, I wondered, was asking the animals?

HARVEY LOCKE may be Y2Y’s human progenitor, but even more influential was a wolf named Pluie. In the early ’90s, Pluie wandered from Banff to Glacier to Idaho and back, an area ten times the size of Yellowstone National Park, her radio collar’s far-flung transmissions testifying to parks’ shortcomings. Pluie served as both mascot and guide, alerting scientists to important corridors and offering a flesh-and-blood illustration of connectivity’s importance.

Though no animal has achieved Pluie’s iconic status, Bob came close. Bob was a bear—“the healthiest, strongest motherfuckin’ specimen you’re ever gonna meet,” Michael Proctor recalled fondly as we walked the rocky lakeside beach near his home in Kaslo, British Columbia. “He made me feel like a marmot.” Proctor—a wiry biologist whose intense gaze suggests that he could hold his own in hand-to-claw combat with a grizzly—caught Bob in a foot snare in 2006 and fixed a radio collar around his giant neck. Then he waited to see what Bob would do.

Bob was a member of the Purcells-Selkirk grizzly population, six hundred bears that roam the mountains of southeastern B.C. near the U.S. border. The population’s boundaries are largely defined by Highway 3, to the south, and Highway 1, to the north. For bears, the human settlements that have sprung up along those thoroughfares represent an oft-fatal temptation. “Orchards, garbage, livestock, cat food—it doesn’t take much for a bear’s nose to draw ’em into trouble,” Proctor said.
The Purcells-Selkirk population is not only hemmed in by humanity, Proctor fears it will someday become internally divided, fatally fractured into a concatenation of micropopulations. A nearby cluster of bears, in the Selkirk Mountains, has as few as thirty grizzlies. It’s a textbook conservation problem: The region’s viable habitat risks deteriorating into an archipelago, surrounded by an ocean of civilization. Absent corridors, the smallest populations are in peril of washing away.

Re-enter Bob. In April 2007, he awoke from hibernation and rambled down the Purcell Mountains toward the Creston Valley, where new greenery was already springing up. There, he hid during the day and emerged at sundown to dine—in the same drab, inglorious fields that Nancy Newhouse and Tom Swann had showed me. Proctor was taken aback: the area’s blandest habitat was being patronized by its most virile resident. Even better, the Selkirks lay just a few miles west. If bears were foraging in the valley, they might also be using it to shuttle between the Selkirks and Purcells. At this innocuous spot, connectivity seemed possible.

Proctor set more traps in the valley and soon caught a female, dubbed Rebecca, who did Bob one better. Not only did Rebecca enter the Creston Valley, she crossed it, spending two weeks in the Purcells before returning to the Selkirks. Proctor relayed his findings to Swann and Newhouse, and, armed with that evidence, Nature Conservancy of Canada—with Y2Y’s financial assistance—eventually bought the land from Wynndel Box and Lumber, the sawmill that owned it. Under the deal’s terms, the Frog Bear Conservation Corridor would remain farmland, with the conditions that it couldn’t be subdivided or built upon.

Michael Combs, Wynndel’s CEO, was pleased with the agreement he’d struck. “How often do you have the opportunity to save a species, protect farming, and, obviously, get a return on the land?” he asked me. Plenty of corporations within the Northern Rockies evince Combs’s brand of compassion-tinged pragmatism. Fording Coal, whose flacks once protested Heuer’s talks, has ceded to Teck Resources, by one metric Canada’s most sustainable company; no matter how cynical you are about a coal company calling itself sustainable, conservationists agree Teck is far more pleasant than its predecessor. Tembec, among southeast B.C.’s dominant logging companies, has donated thousands of acres of easements to NCC. By any measure, the region is light-years removed from the distrustful 1990s, when the Union of British Columbia Municipalities passed a resolution condemning Yellowstone to Yukon.

Nonetheless, Tom Swann described NCC’s relationship with Yellowstone to Yukon as a “delicate dance.” After all, NCC prides itself on relationships with loggers, miners, and ranchers, and Y2Y’s name still isn’t golden everywhere. In southern Alberta, where grizzlies are trundling onto the prairies for the first time in a century, I met with ranchers who were modifying their operations to accommodate bears—installing grizzly-proof grain bins, better disposing of dead livestock, giving up raising sheep. Y2Y and others have nurtured those efforts, and one environment-minded rancher had recently held a seemingly productive meeting with conservationists. Bears were more numerous than people realized, the rancher told the greens, and emerging science corroborated his observations. The conservationists seemed to agree—but in subsequent quotes in the media, they continued using low-ball population estimates.

“They’re looking at the same stats as us, but they pick the numbers they want to use,” the disappointed rancher told me. “My opinion is that if they tell the whole story it won’t look as bad, and so they’re not bringing in as much money.”
Whether that’s fair or not, Y2Y’s greatest asset is indeed its narrative. The constant risk, however, is that the grand story becomes grandiose, consuming local efforts that, in many cases, predate Y2Y’s involvement. That’s why Michael Proctor keeps himself at arm’s length—not because he’s a glory hound, but because the perception that his research is driven by Y2Y’s agenda could alienate some collaborators. “Just make it clear in your article that I’m an independent biologist—I don’t work for them or anybody else,” he told me with a wry smile. “And if you mess that up, remember that I’m very good at setting leg snares.”

THREE WEEKS LATER on my Y2Y road trip, I found myself clinging to an upper limb of a gnarled apple tree, picking fruit for conservation. I was in a backyard in Missoula, Montana, three hundred miles south of Canmore as the golden eagle flies, on a house call with Monica Perez-Watkins, office manager at the Great Bear Foundation. Perez-Watkins was perched in the branch above me, poking at a stubborn apple with a telescoping pole. With a deft flick, she dislodged the red globe; it caromed earthward through the foliage and came to rest in the grass. We clambered down to gather the fallen fruit.

“This is the thirty-second site of the season,” said Perez-Watkins, a lanky woman in a black sweatshirt and enormous sunglasses, as we scooped apples into a paper bag. “And since there’s usually more than one tree per site, we’ve probably done”—she paused to perform some mental math—“almost one hundred trees.”

The link between collecting fruit and connecting habitat is not, upon first blush, obvious. On the north side of Missoula, where the Rattlesnake Wilderness sweeps down to meet suburban development, abundant apple trees often seduce black bears in fall, when the fruit ripens and the creatures are prowling for calories. To forestall conflicts between ursids and people, the Great Bear Foundation, one of Y2Y’s partners, operates a program called Bears and Apples, through which staff and volunteers pick bare the trees of willing landowners. (The apples go to cider presses, food banks, and homeless shelters.) Thanks partly to the foundation’s efforts, said cofounder Chuck Jonkel, the once-fraught relationship between humans and bears has, at least in the Rattlesnake, de-escalated into something resembling harmony. “It takes a long time to get people to not only live with bears, but to behave,” Jonkel told me. “It’s like driving a car for the first time—there are rules you have to learn.”

Imparting and enforcing those rules—pick your apples, lock your dumpsters, replace the wooden walls of your grain bin with aluminum—is not, perhaps, the sexiest part of connectivity. Yet if open garbage and untended chickens lure wildlife into the deadly embrace of civilization, conservation easements and wildlife crossings will be nothing but bridges to nowhere. Within the vast expanse of Yellowstone to Yukon, the apparently mundane field of attractant management has produced some of the most intriguing innovation. In Montana’s Blackfoot Valley, for instance, I inhaled the odor of rotting meat at an electric-fenced facility where ranchers were composting livestock carcasses within towering piles of wood chips. For years, dead cattle had simply been hauled off to ranch boneyards, where they inevitably drew grizzlies into trouble; in 2003, however, a collection of local ranchers called the Blackfoot Challenge began transforming the corpses into compost, which the state now uses in roadside revegetation projects. According to Seth Wilson, biologist at the Blackfoot Challenge, the arrangement has reduced grizzly conflicts by some 90 percent. “Getting dead carcasses off the landscape is low-hanging fruit for large carnivore conservation,” he said as I inspected a stray femur.

As Y2Y and its satellites have pioneered new approaches, they’ve become models for large-scale connectivity efforts on six continents. The European Green Belt, a network of habitat that was incidentally protected by the Cold War’s Iron Curtain, will someday run north to south through twenty-four countries, from the Barents Sea to the Aegean. “Peace parks”—border-spanning protected areas that allow wildlife to migrate unfettered by geopolitics—have sprung up in Africa. A proposed Atlantic Megalinkage would run from Florida to Quebec, joining ecosystems like Georgia’s coastal plains and Vermont’s Green Mountains.
Some connections, inevitably, have collapsed: Paseo Pantera, an epic corridor planned for Central America’s Atlantic Coast, stumbled under the weight of its own bureaucracy. But more have flourished. There are vegetation connectivity projects in Australia; corridors between savannah and wetlands in Brazil; highway crossings in China, Mongolia, and Turkey. “I can say the name Y2Y just about anywhere on Earth, and people know what it means,” Harvey Locke told me. “Our idea isn’t the template that everyone else obeys, but it’s certainly the archetype.”

IN LATE OCTOBER, our trip ended where Heuer’s once began: Yellowstone National Park, where the buffalo roam and the SUVs idle to take their picture. At the entrance lingered pronghorn and elk, as comfortable around humans as household pets. The next morning, I glanced out the window of our cabin to see a burly gray wolf staring back. The wolf crouched like any domestic canid and dropped a ribbon of scat before vanishing into the timber.
No grizzlies, though. It made for an anticlimax: We’d spent two months obsessing about the ursine ghost in Y2Y’s machine, examining the electric fences and conservation easements that had been completed in their honor, like offerings left for a deity. Yet the closest we’d come to laying eyes on one was a tuft of coarse chocolate hair, snagged by a coil of barbed wire in northern Idaho.

We drove southeast from Grand Teton on the last day of October, the sun a red ball on the horizon. Cruising down the eastern slope of the continental divide, we rounded a curve to find a pickup parked in a pullout, the driver craggy beneath his cowboy hat. He lifted a finger from the wheel and nodded toward the embankment across the road. My companion slammed the brakes.

Atop the roadbank, where dirt hit timberline, lumbered a female grizzly, enormous muzzle swinging beneath the hump of her shoulders, haunches rippling under silver fur. Two German Shepherd–sized cubs trailed behind, snouts to the ground. A radio collar encircled the mother’s tree trunk of a neck. We snapped pictures and pondered our good fortune: there might have been, at that moment, a few grizzlies farther south in North America, but not many.

Back home, I called Dan Bjornlie, carnivore biologist with Wyoming Game and Fish; perhaps he knew the bear’s fate. I gave him the details and heard him typing, searching his database. “That might have been Bear 718,” he said at last. “She’d been hanging out around the pass.”

Though 718 hadn’t roamed much, other bears in the Greater Yellowstone Ecosystem are on the move. The population has grown over the decades, from fewer than 150 to around 700, and as their numbers have increased, Yellowstone’s core has proved too small. They’ve pushed down the Wind Rivers toward Pinedale, down the Wyoming Range south of Jackson, east onto the plains past Cody. Four years in a row, Game and Fish has confirmed sightings in South Pass—closer to Utah than to Montana. To Bjornlie’s surprise, the bears are surviving their forays. “The rate of mortality hasn’t increased as fast as distribution,” he told me.

Yellowstone to Yukon certainly doesn’t deserve direct credit for Wyoming’s wandering grizzlies. Still, the needle has moved; whether Y2Y pushed it is, in a sense, beside the point. Two decades ago, any animal that strayed beyond park boundaries was liable to catch a bullet or get pancaked by a car. While those dangers linger, we’re better at coexisting with wildlife than at any time since wagons first rolled West. Even hidebound bodies like Alberta’s provincial government and the U.S. Forest Service are including corridors and connectivity in plans and rules. “If you try to connect all the dots, it’s sometimes hard to see the exact path,” Heuer told me in Canmore. “Did Y2Y have a part to play in those decisions? Absolutely. What specific part, and to what extent? I could never tell you.”

In the winter of 2015, Heuer bowed out from his own part in Y2Y. Though he cherished the mission as much as ever, being confined to a desk gnawed at him. He felt anxious; he stopped sleeping. Finally he quit, desperate to reacquaint himself with the lands and animals he’d tasked himself with saving. These days he’s leading the reintroduction of bison to Banff National Park, though he remains connected to Y2Y as an adviser and volunteer. “People see careers as linear things, but some explorers have to go up into the box canyon,” Heuer told me when last we spoke. He sounded liberated.

The patience to explore box canyons is a luxury that conservation doesn’t always have. The threats are perpetual and protean: there’s the fracking boom in British Columbia; the industrialization of Canada’s parks; the mining plan approved for the Yukon. Maintaining connectivity requires constant pressure. Sometimes, though, we can only set the stage upon which nature will perform. Grizzlies once ranged far beyond Y2Y’s borders—into Utah, Colorado, New Mexico. We’ll know Yellowstone to Yukon is working when it begins to feel small.

Ben Goldfarb’s journalism has appeared in High Country News, Earth Island Journal, The Guardian, and other publications. He received a master’s degree in Environmental Management from Yale University. This story was supported by the Solutions Journalism Network.


Sunday, January 3, 2016

Scientists say that 6,000 years ago, humans dramatically changed how nature works

There’s no doubt that humans have changed the face of the planet in countless ways since we first arose as the dominant species on Earth. Many of our most obvious impacts have become apparent in the past century or so, with the rise of concerns about climate change, habitat destruction, pollution and the loss of biodiversity.
But new research reminds us that humans have actually been reshaping the planet for thousands of years, in ways we’re only just beginning to understand.

A paper published Wednesday in Nature suggests that human activities caused a major shift about 6,000 years ago in the way plant and animal communities were structured on Earth — this was after the start of the geological epoch known as the “Holocene,” an era which includes the growth of human populations and their rising influence around the globe. The study compared data from the fossil record with observations from the modern era to reach its conclusions.

A new analysis of the fossil record by scientists at the Smithsonian’s National Museum of Natural History has revealed that the structure of plant and animal communities changed significantly about 6,000 years ago, around the time agriculture began to spread across North America. The study drew on the museum’s paleobiology collections and focused on 360,000 pairs of organisms in 80 plant or mammal communities on different continents, including groups that existed up to 307 million years ago, as well as modern communities and communities from the recent past. (Image credit: Chip Clark, Smithsonian)

“I would say that what we can take from the fossil record, in particular, is an understanding of how communities changed naturally before humans arrived in the picture,” said the paper’s lead author, S. Kathleen Lyons, a paleobiologist at the Smithsonian Institute’s Evolution of Terrestrial Ecosystem’s program. Comparing these findings with observations from after the rise of humans allowed the researchers to better understand how humans have changed the Earth.
What “species pairs” can tell us about nature
The work investigates the structure of plant and mammal communities throughout the past 300 million years by examining species pairs. Scientists have observed that sometimes two species tend to be “aggregated,” or paired, meaning they frequently show up in the same place together.
This probably has something to do with the way the species interact with one another or with their surroundings, Lyons said — either they both depend on the same type of habitat, and thus tend to be found in the same places, or they depend on each other for survival in some way. She listed the cheetah and the giraffe as a modern-day example — they tend to be found together because they’re both savannah organisms and share the same type of habitat.
The opposite can also be true. Some species tend to be segregated, rather than aggregated, meaning they aren’t found together. Either they simply require very different types of habitats, or living too close to each other is bad for them in some way — perhaps they compete with each other too much for food and other resources to live too close together.
The key to remember here is that species can also occur in nature totally at random, sometimes being found together and sometimes not — in fact, this is what’s considered usual for most organisms. In order to be considered aggregated, species need to be found together more often than one would statistically expect to happen by random chance — and in order to be considered segregated, they must occur separately more often than one would expect to happen by chance. When this happens, the statistics suggest that some force or environmental pressure is either keeping the species close together or consistently driving them away from each other.
By looking at the fossil record, the scientists found that aggregated species pairs were dominant on the Earth — in other words, there were more aggregated pairs than segregated pairs — starting from about 300 million years ago and continuing up through the beginning of the Holocene.
Then, about 6,000 years ago, there was a shift, and segregated pairs became dominant. Obviously, something had changed the way plants and animals interacted with each other and with their environments — the question that remained was what might have been the cause. The researchers had two main theories: the first was that changes in the climate were responsible, and the second was that some kind of other biological pressure, likely human activities — which were on the rise during this period in history — was to blame.
The power of human influence
The researchers were quickly able to rule out climatic influences by once again looking at the past. They examined data from ice cores — ice samples taken from the polar ice caps — to see how the Earth’s climate had changed over millions of years. The polar regions contain snow and ice that’s been around for millennia. By examining their composition, scientists can learn what Earth’s temperature and other aspects of its climate were like millions of years ago.
They found that while the planet’s climate varied throughout the past few million years, there were no major shifts in plant or animal community structure — that is, how aggregated or segregated species pairs were — corresponding in time with these climate variations.
Thus, they concluded that biological pressure from the rise of human activity during this time period was the likely cause. The exact mechanisms remain unknown, but Lyons points out that human populations were growing and agriculture was beginning to catch on in North America (where a majority of the data used in the study came from) around this same time.
“I do want to emphasize [that] we don’t have a smoking gun of mechanisms for what activities humans were doing,” Lyons said. But the combination of all their growing activities on Earth during the early- to mid-Holocene was likely causing barriers to the spread of different organisms throughout their habitats, she said. Perhaps settlement by humans, and their cultivation of land for agriculture, was making it hard for some species to settle down in areas they otherwise used to dominate.
Additionally, Lyons noted, some species were probably driven away from certain areas because it was too difficult to compete with humans for resources, such as food or space. The combination of these factors means that certain organisms, which for the past 300 million years were often found together, suddenly were splitting apart after being forced to adapt to the changing landscape that humans were reshaping.
Using the past to understand the future
While one could argue whether the specific shift from aggregation to segregation is good or bad (or totally neutral), the real takeaway here is the power that humans have to bring about large-scale changes in the environment — a power that’s most obvious today, but in fact has existed since human civilizations first started to become dominant on the Earth. A debatable point, however, is how useful this revelation is for making predictions about the way organisms might react to environmental pressures in the future.
In their paper, the authors have written, “Future work comparing the co-occurrence structure of fossil and modern communities should allow us to better understand how this alteration will play out in the future.” In other words, the authors argue that looking at past ecological shifts can help us understand what kinds of changes humans might bring about in the future.
Gregory Dietl, curator of cenozoic invertebrates at the Paleontological Research Institution, takes this stance as well — but he cautions that not all scientists feel this way. Dietl, who served as a reviewer on the new study before it was published, authored a “News & Views” piece (also published Wednesday in Nature) reacting to the new paper. In the piece, he pointed out that the results in this study show a clear difference between modern-day plant and animal communities — which have been reshaped by human influences — and ancient communities. And he noted that some scientists have argued that the past is so different, we can’t necessarily use it to make inferences about the future. As he wrote in his piece, “At stake is whether we can reliably use the past as a guide to an uncertain, anthropogenically modified future.”
Dietl told The Post that he feels the past can still be used as a tool for understanding the future, even if it looks so much different from the present day. Doing so successfully just requires careful and creative thinking.
Scientists often try to gain insight into the future by looking for periods in the past during which conditions were similar to those in the present — these similar periods are called “analogues.” Then, by examining how the environment reacted to those conditions in the past, they can get a glimpse at how similar conditions in the present might affect the future.
By choosing analogues carefully, scientists can gain insight into the future — not by making exact predictions, necessarily, but by coming up with “alternate interpretations of what might happen in the future,” and then making informed inferences about which potential future scenarios are most likely to occur, Dietl said.
And Lyons agreed that this paper, and others like it, are useful for understanding the future. The fossil record clearly shows what plant and animal communities looked like before human influence and what they looked like after, she said.
“What this allows us to do is understand areas where humans are having an effect,” she said. Then, in present-day studies, scientists can examine the ways natural communities are changing and make better-informed inferences about which of these changes might have been caused by human influences.
And, if this study has any say on the matter, human influences are a powerful force on the face of the planet. Knowing the power humans have been able to exert — just from our mere presence on Earth — over the fundamental structure of natural ecosystems is, at the very least, a wake-up call about the changes we may cause in the future.