Acts of Faith
Cristina Eisenberg, PhD
In early 2003, a two-year-old male lynx was cruising through his territory near Kamloops, British Columbia, searching for snowshoe hares. He maneuvered through the forest, padding easily in deep snow, his large feet acting like snowshoes. All at once, what should have been just another in a lifetime of simple steps turned ill-fated. He found himself caught. No matter what he did, he could not free his foot from the hold of a trap. Soon a human came along and jabbed something sharp in his rump, which put him to sleep. When he awoke, his life had changed in surprising ways.
Although the young lynx didn't know it, at this point, in addition to a bulky collar, he had acquired a name: BC-03-M-02. He soon found himself translocated to Colorado as part of the Colorado Division of Wildlife's (CDOW) lynx reintroduction program. Eventually he was released into southern Colorado's high country. It was much drier there than his northern Rocky Mountain home where he was born, but there were plenty of snowshoe hares, his preferred food, to eat. As important, he found a willing, fecund mate. Life was good; in two years he sired three litters of kittens. And then one day in late 2006, something in his brain, some inchoate longing, some homing instinct, made him feel like roaming. At first he simply traveled from one snowshoe hare stronghold to another, finding food when he needed it. After a while he started ranging farther, and eventually just kept going. He ended up crossing landscapes unlike any he'd experienced before: the Wyoming Red Desert, followed by the Greater Yellowstone Ecosystem.
Lynx after its primary prey, the Snowshoe Hare |
Biologists determined that over the next months the lynx covered 2,000 miles. His last recorded collar signal before the battery gave out, occurred in late April, 2007. Eventually BC-03-M02 found his way remarkably close to where he was born, near Banff National Park, Alberta. And there his life ended, in another trap line—a lethal one set to legally harvest fur-bearing mammals. Superbly healthy at the time of his death, well-fed, with a luxuriant coat of fur, he set a world record for the longest known distance traveled by his kind. Despite his tragic end, BC-03-M02 proved that even in our fractured world, it is possible for a carnivore to roam widely to meet his needs for food, a mate, and travel corridors. But ultimately, the media hoopla about how far he had traveled belied the tragedy of his death.
The lynx is a species with a large home range and the ability to travel far. In recent years, lynx from the CDOW reintroduction project also have dispersed south, into New Mexico's mountains. Researchers did not anticipate these dispersals, which involved crossing interstate highways, traversing areas of high human use, and dodging death in a multitude of ways. En route, these dispersers had to find snowshoe hares to eat—not an easy task. Indeed, I consider such landscape-scale peregrinations to be acts of faith.
Other species besides lynx have an innate need to wander. These instinctive journeys involve both migration, defined as seasonal, cyclical movements from one region to another and back for breeding and feeding purposes, and dispersal, which is the process organisms use to permanently spread from one place another. Many species migrate—from pronghorn to elk to bison—as part of their annual life cycle and natural history. Fewer species disperse. Much has been written on migration. For example, in a recent High Country News article (http://www.hcn.org/issues/43.22/protecting-wildlife-corridors-remains-more-theory-than-practice), science writer Mary Ellen Hannibal focused on the path of the pronghorn, one of the most at-risk migration corridors in the Rocky Mountains, and on Wildlands Network's efforts to raise awareness of these issues.
suggested wildlife corridors in North America
suggested wildlife corridors in North America
Here I focus on large-carnivore, continental-scale dispersals—why they matter, and what we can do to preserve these vagile species' fragile corridors. Wolves, wolverines, lynx, and cougars have natural histories that often include large dispersal patterns. Other species, such as grizzly bears, also disperse, although their movements are typically smaller compared to the other large carnivores. In our developed world, landscape-scale dispersals are becoming increasingly challenging for all species.
Lifelines: Why Cores and Corridors Matter
In their Island Press book, Corridor Ecology, ecologist Jodi Hilty and her colleagues describe nocturnal photographs taken from space of terrestrial light emissions. These satellite images depict millions of bright dots strung into lacy, incandescent webs of light across the United States. These dots indicate the presence of humans and their cities and other forms of development. They clearly show, for example, the myriad roads that crisscross and dominate our nation. The negative spaces—the dark areas—which make up a sobering minority of what one sees in these images, speak volumes about how broken up by human development our nation has become.
Landscape fragmentation represents one of the leading conservation issues we face today. Scientists and conservation organizations such as Wildlands Network are striving to link landscapes to conserve wildlife and biodiversity and create ecosystems more resilient to climate change. For the past two decades, preeminent conservation biologists Michael Soulé, John Terborgh, and colleagues such as Dave Foreman have been urging conservationists to connect and rewild landscapes on a continental scale, to enable creatures, particularly those with sharp teeth and claws, to thrive. Carnivores, Soulé has long asserted, need room to roam. And carnivores, most scientists agree, are bellwethers of the health of an ecosystem. They recognize that an ecosystem that is sufficiently intact to support large carnivores likely also has the capacity to support a wealth of other species, such as songbirds and amphibians.
(this fragmented forest still provides a connective path for carnivores)
(this fragmented forest still provides a connective path for carnivores)
There are many stories on the landscape, evocatively told via the carnivores' feet, along the Spine of the Continent. Wildlands Network has identified this cordillera as one of four continental Wildways (large landscapes for wildlife movement). The Spine of the Continent spans the Arctic to the sub-tropics, running from Alaska to Mexico. Plant and animal species have used this, and the other Wildways (the Arctic/Boreal Wildway across the top of the continent; the Pacific Wildway down the West Coast to Baja California; and the Atlantic Wildway stretching from Florida to Canada's Gaspé Peninsula), as movement corridors since the retreat of the ice sheets during the Pleistocene Epoch.
Twelve thousand years ago, two ice sheets covered much of North America: the Laurentian, which ranged over most of Canada, and the Cordilleran, along the Pacific coast. The Spine of the Continent Wildway arose as these ice sheets receded, opening a path between them, called the Mackenzie Corridor. As the climate warmed, this corridor gradually widened, creating a passage for plants and animals. In time, lush forests arose, and large mammals began to inhabit and move through the steep slopes and fertile valleys of the Rocky Mountains. Today, animals continue to use this ancient migration and dispersal pathway. It's part of their ancestral memory; it's in their genes. Indeed, I like to think of it and the other Continental Wildways as "carnivore ways," because of the carnivores who have worn deep trails in them since time immemorial.
The Oregon Wolf OR7 found enough greenspace to wander to Calif.
The Oregon Wolf OR7 found enough greenspace to wander to Calif.
Today we are using every tool possible to study human land use impacts on animals whose natural histories require abundant room to roam in order to thrive. Radio collars have been lauded as one of the major wildlife science breakthroughs of the 1970s. Until this technological development, biologists answered questions about wildlife use of a landscape via track and scat surveys and thousands of hours of field observations. Such meticulously gathered data provided much useful information, but at best could only provide an approximation of wildlife movements. Since radio-collars became widely available in the 1990s, their technology has been incorporated in many wildlife studies. While many of us prefer non-invasive monitoring methods, such as wildlife tracking, there are times when the collars provide an essential and otherwise inaccessible window into the large carnivore world. On several recent occasions, precious data from these collars have told remarkable stories about the animals that have worn them, such as lynx BC-03-M-02, and the corridors they use to move across our continent. Thus, collar data have expanded our awareness in astonishing ways of how best to conserve wolves, wolverines, lynx, and cougars, which need enormous amounts of room to roam.
Wildlife corridors are passages that allow animal movements. They can vary greatly in scale and shape from species to species; some are linear routes, others are intricate networks linking habitat patches. All provide wildlife with core habitat essential for species survival. Thus these corridors function like Lifelines (as coined by Wildlands Network), enabling animals to flow from one core area to another. Barriers to this basic need to move, such as human development, provide formidable threats to long-term survival of a variety of species. For the large carnivores, it's not just about losing freedom to move, it's about losing a natural process. Dispersal is one of their key survival mechanisms, used to maintain genetic diversity. Additionally, scientists have recently recognized that these corridors are necessary to help animals adapt to climate change. This means without open corridors, many of the large carnivore species may be doomed.
Upon reaching adolescence, many of the large carnivores develop an irresistible urge to leave their birthplace, find a mate, and establish their own territory. Thanks to the collars that some of them wear, we have discovered animals the likes of which nobody had seen in many decades turning up in unexpected places, via dispersal. We have also learned about the tortured paths these animals have taken. Ten thousand years ago, when the North American Continent consisted of vast, unbroken tracts of land, these dispersals were probably fairly straightforward. But today, given our fragmented continent, such dispersals literally amount to acts of faith. Faith that by acting on ancient instincts, these animals will find what they need to persist as individuals, and beyond that, as species: a safe home, suitable habitat, and a mate.
Freedom to roam; essential to sustain carnivore populations into the future
Freedom to roam; essential to sustain carnivore populations into the future
Audacious as such dispersals may seem, the animals that make them can't help trying to do so. It's imprinted in their DNA; it's part of the shape of their bodies and how their minds work. Moreover, they do it with casual grace, as if these heroic dispersals amounted to just another day in their lives. There goes a wolf, loping a thousand kilometers in a harmonic, energy-conserving gait, its hind feet falling perfectly into the tracks left by its front feet. And a wolverine, artlessly running up mountains and back down them again in minutes, covering more ground and elevation—more rapidly and for longer distances—than just about any other terrestrial mammal is capable of doing. But the operative word is "trying." If it were a simple act of will, most of these stories would have happy endings. The stark reality is that these dispersal attempts are often met with at least as much failure as success.
As a conservation biologist who works with wolves, I have experienced my share of dispersals, some with tragic endings. But nevertheless, such dispersals fill me with hope that perhaps we will get it right soon, given the opportunities and powerful lessons these animals are conveying. Certainly, the undaunted spirit carnivores demonstrate has the power to capture the public imagination and mobilize entire conservation movements.
The Carnivore Way
In February 2008, in California's Tahoe National Forest, while doing an American marten study, Oregon State University graduate student Katie Moriarty's remote-sensing camera photographed what appeared to be a wolverine. The grainy image created a furor in wildlife science and conservation circles. It was California's first substantiated wolverine sighting since the 1920s, although this species' presence there had been long rumored.
At the time of Moriarty's photograph, the nearest known resident population was about 900 miles distant, in Northern Washington. DNA tests of collected scat samples from the animal proved that it was genetically related to Rocky Mountain wolverines, rather than to historic California specimens found only in museums. Thus, most experts believe this animal dispersed from an out-of-state population. How the photographed wolverine got to California will ultimately remain a mystery.
In spring 2009, another young, male wolverine, M56, captured as part of the Greater Yellowstone Wolverine Program, dispersed over 600 miles, across a portion of the Great Divide Basin, crossed Interstate 80 on Memorial Day weekend, and turned up in Rocky Mountain National Park, Colorado. This marked the first verified occurrence of a non-translocated wolverine in Colorado.
Also in spring 2009, a two-year-old female Yellowstone wolf wearing a state-of-the-art Argos collar made an astonishing 1,000-mile journey to Colorado and ended up not far from one of my study areas, the High Lonesome Ranch in north-central Colorado, where I work as the research director. The ranch comprises a sublime, 300-square-mile hunk of deeded and permitted Bureau of Land Management lands located in Colorado's Rocky Mountain west slope. Its rugged, aspen-crowned mountains and deep, fertile valleys hold healthy deer and elk herds and provide a home to abundant cougars, black bears, and more. Threatened and endangered species returning to this part of Colorado include wolf and lynx.
It's not exactly safe to be a wolf in Colorado; human tolerance for this species is low. Since initiating our food web research on this ranch, we have been referring to the roving canids that may be recolonizing this area from the Greater Yellowstone Ecosystem as "visitors from the north." SW341WF, as she was called, hung around Eagle County, Colorado for a few weeks but was eventually found dead after ingesting poison.
In yet another astounding dispersal, in June 2011, a young male cougar turned up in Connecticut, road-killed by a sports utility vehicle. The 140-pound cougar was in good health at the time of its death. DNA tests furnished genetic evidence that he had traveled 1,500 miles from the Black Hills of South Dakota, via Wisconsin and Minnesota, to suburban Connecticut. Further, during the summer of 2011, multiple cougar sightings in Pennsylvania, one of the states through which this animal had passed, helped document his continental-scale dispersal. This cougar set a record for the longest dispersal ever recorded for his species, and provided the first confirmed cougar presence in Connecticut in over 100 years.
The most recent dispersal story began in the fall of 2011. In October of that year, the Oregon Division of Fish and Wildlife (ODFW) began posting on their website maps of a dispersing young male wolf, known as OR7. In these maps, a thick, black, zigzagging line depicted his path subsequent to his September dispersal from northwest Oregon's Imnaha pack. The ODFW regularly updated these maps to show OR7's persistent southwestern trajectory. He cut a swath through the state, to the southwest Oregon Cascade Mountains, but stayed out of trouble. Just before Christmas, the news reported that he had settled down near Crater Lake.
Over the previous three months, public attention had been riveted on this young male wolf as he wandered around Oregon likely in search of a mate, looping and doubling back, but each week trending farther south. Just after Christmas, a question arose publicly: how low would this vagabond wolf go? Others wondered whether he was looking for love in all the wrong places. Just before New Year's Eve, the public got their answer to the first question. OR7 had crossed into California, becoming the first wolf confirmed in the state since 1924. Time will tell the answer to the second question.
These transboundary stories make our hearts beat a little faster and give rise to complex emotions: wonder, grief, hope. How many other such dispersals have there been of which we are unaware? Why do half of these stories have tragic endings? And how can we improve these outcomes, now that we are aware of them?
Mending the Web Footstep by Footstep
Mending fragmented landscapes and restoring their ecological function is one of the most urgent conservation topics in our rapidly changing world. Creating connected, landscape-scale permeable corridors for large carnivores and other species can provide an essential tool as we strive to cope with global change and mitigate the effects of a burgeoning human population. As a scientist who studies the effects of wolves on biodiversity and whole food webs, I have found that restoring large carnivores to degraded ecosystems is one of the simplest, most effective, and cost-efficient ways to create healthier, more resilient ecosystems.
Why carnivores? Because they are what Soulé and his colleagues refer to as, "strongly interacting species,"—species that have large effects on whole ecosystems. In their seminal Island Press book, Trophic Cascades: Predators, Prey, and the Changing Dynamics of Nature, conservation biologists John Terborgh and Jim Estes explain that predation is intrinsic to maintaining life in all its forms. Each act of predation allows other organisms to live. Terborgh and Estes provide innumerable examples of how predation thus enables energy to flow freely through whole food webs, releasing nutrients for use by other species. These dynamics, which shape all ecosystems from aquatic to terrestrial, directly and indirectly stimulate plant growth. For example, by preventing elk from standing around in one spot, eating saplings to death, wolves can indirectly enable aspen trees to grow taller. This ecological cascade thus creates habitat for other species, such as songbirds.
In addition to raising awareness of the ecological value of large carnivores, Wildlands Network has been working to shift the conservation movement's focus from preserving individual, often isolated, protected tracts of land which, for large carnivores and other species, essentially amount to habitat "postage stamps," to a landscape-scale approach. This approach is defined by conservation that looks beyond human-drawn borders toward land management at ecologically relevant scales, such as ecoregions. OR7 and his comrades embody and exemplify Wildlands Network's conservation vision. Specifically, Wildlands Network is applying a science-based approach to connect core landscapes so wolves, wolverines, lynx, cougars, bears, and many other species, such as pronghorn antelope, have room to roam. The mounting pressure of climate change further necessitates leaving ample connected habitat for herds and individuals of innumerable species to be able to find and populate new homes. These goals require identifying and designing critical wildlife road crossings to reduce wildlife/vehicle collisions; bringing a large-landscape approach to ecosystem restoration and conservation practitioners; raising awareness of the importance of protecting carnivores when restoring whole ecosystems; and inspiring private lands conservation.
without adequate wildlife crossings, Florida dept of transportation posts signs where Pumas often cross highways
without adequate wildlife crossings, Florida dept of transportation posts signs where Pumas often cross highways
In the past decade, Wildlands Network scientists have become aware that long-term survival of biodiversity, including large carnivores, depends on conserving a continental-scale network of permeable lands under a variety of ownership designations—not just public lands. In fact, the majority of these lands are privately owned. Accordingly, Wildlands Network has been leading the charge to raise awareness of the importance of private working lands such as the many large ranches in the West. Establishing compatible uses on these working lands to achieve landscape-scale conservation involves fostering collaboration among landowners, scientists, corporations, and conservation partners.
Inspired by iconic American ecologist Aldo Leopold, High Lonesome Ranch chairman/CEO and Wildlands Network Board member, Paul R. Vahldiek, Jr., hopes that his quintessential western landscape will serve as a land ethic blueprint for private lands. Vahldiek and his partners' key restoration strategies include reducing habitat fragmentation and conserving top carnivores. Their efforts involve predator-friendly ranching, stream and grassland restoration, and using hunting as a conservation tool. They are working closely with Michael Soulé, who is helping to guide High Lonesome Ranch food web research, and with Wildlands Network Strategy Director Kenyon Fields, to advance private lands conservation on a continental scale, and to partner with other landowners to foster similar conservation efforts.
As a researcher who works on both federally protected lands, such as Glacier National Park, Montana, and Waterton Lakes National Park, Alberta, as well as private lands, such as the High Lonesome Ranch, I strive to use my science to help contribute to the legacy of continental conservation that Michael Soulé, John Terborgh, and their colleagues established. But further, as a plain member of the biotic community, as Leopold put it nearly a century ago, I consider it my duty to help advance whole-ecosystem conservation to create a more sustainable future for our children and the creatures with which we share this earth. But it takes a village and more to succeed in this effort. Achieving continental-scale conservation to safeguard the survival of animals such as lynx BC-03-M-02 takes networks of people creating networks of permeable lands. Thanks to Wildlands Network and partners such as the High Lonesome Ranch, mending our tattered web is progressing steadily, footstep by footstep along the carnivore way.
In future months you will undoubtedly be stirred by fresh stories about long-distance animal dispersals. I have faith that as we further mend the web and our conservation networks grow and thrive, more of these stories will have happy endings.
* * *
Cristina Eisenberg is an ecologist and Wildlands Network advisory board member who studies how wolves affect ecosystems throughout the West. She has completed her doctorate at Oregon State University and is working on a book for Island Press on large carnivore conservation on a continental scale, The Carnivore Way: A Transboundary Conservation Vision in a Changing World. In her first Island Press book, The Wolf's Tooth: Keystone Predators, Trophic Cascades and Biodiversity, she explored the many ways that keystone predators shape ecosystems.
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