It is a rule in ecology that big animals outcompete little animals. Sometimes the big animals kill the little animals, sometimes the big animals eat the little animals, and sometimes the big animals drive the little animals out of one territory and into another, safer one. That basic pattern – “interspecific competitive killing” – has pushed scientists to try to understand how large carnivores shape entire ecosystems. Continue reading
Reintroduction
George Monbiot: For more wonder, rewild the world
Ghosts of the Appalachians or the Missing Actors?
When we pass through the Appalachian Mountains along its vast extent from the humid southeast of Alabama and Georgia to the cold and barren of Nova Scotia and Newfoundland, we cannot help but marvel of its beauty and extensiveness. Unlike its western cousin, the Rocky Mountains, which is a mixture of forested ranges imbedded in a matrix of lowland shrub and grass ecosystems, the Appalachians are heavily forested mountains imbedded in what is likely one of the largest forest ecosystems in the world. One can only imagine the extensiveness of the original eastern forest, extending to the north as far as the tundra, to the south to the Gulf of Mexico and to the west until the beginning of the Great Plains. It is this eastern “endless” forest that provided the opportunities and resources to the Earlier Americans who lived there for centuries. It is also this bountiful forest that gave the European explorers who followed their toehold on the continent. Rich in plant and wildlife resources, the eastern forest likely had one of the highest densities of Earlier Americans in North America. Even today, the eastern forest continues to support the highest density of Current Americans.
Much has been written about the destruction of the eastern forests by early European colonists and their descendants. However, today past abuses and scars of these earlier settlers have been covered over by an extensive mantel of young and thriving forest mixed in with verdant farmland. In fact, the structure of the current forest ecosystem of the east is probably much like that before Europeans arrived, a mixture of open farmland and dense forest. Today, as in those earlier times, the open farmland provides areas of high productivity where many species of wildlife can find food while the forest provides shelter from the elements.
To the viewer’s eye, it would seem that the eastern forests, especially the Appalachian Mountains, have returned to much of their former beauty and glory. Even in the more populated areas of the East, the forest extends its fingers into the fringes of the cities. It is only in the East that abandoned land quickly reverts to forest! In these extensive forests all along the eastern seaboard, abundant wildlife, small song birds and mammals, larger turkeys, hawks, and even larger deer and bear, are again abundant in many parts of the Appalachian chain. Though much was lost in the past, the recuperation of the eastern forest ecosystem throughout the eastern seaboard makes it a true success story, a paradise gained! All this in light of one of the highest human densities in North America!
But has the Eastern Forest truly returned to its past glory as an ecosystem? An ecosystem is not like a museum, not just a static collection of parts, plants and animals. It is a dynamic entity, one that constantly changes, grows, dies. All its parts have a function, a function vital to the health of the ecosystem. The plants of an ecosystem function as extensive solar traps, each day, month, year, capturing immense amounts of solar energy. That energy is transferred along to other parts of the ecosystem in a cascading chain of actions reaching the smallest corners, maintaining the diversity of life found there. In each step, energy is transferred, energy is lost. Eventually that energy passes out of the ecosystem, replaced by new waves of solar radiation. In a true sense, the function of an ecosystem is this transfer of solar energy from one component to the next. It is this energy transfer that keeps the ecosystem “alive”, maintaining its integrity and its diversity.
The role, then, of plants and animals in the ecosystem is in successfully performing this transfer. This is no small task and like an elaborate play, is accomplished by a well choreographed cast of thousands, of millions, playing parts honed by millennia of co-evolution. All this is carried out on the stage of the ecosystem, the physical, the biological props and scenery that we see. For most of the players in this production, theirs is a dual role, they capture that energy and pass it on to others. They are both consumer and consumed, predator and prey. Half of the ecologically important role of prey is to be eaten by their predators. In doing so, they pass their energy on to the next step, fulfilling their ecological mission. How this is all done is the intrigues, the sinuous plots of this elaborate play. At each step, the predators, take the energy to the next level. Many of these predators, in turn, have their own predators, fulfilling their dual role. That is how the system works. In each step, energy is transferred, energy escapes, leaving less energy for the next consumer, the next predator.
What is that final passage of energy within the system? Who are the ultimate or “top” consumers/predators? It is the largest predators, the Wolves, the Cougars, the Lions, animals that normally don’t have another predator trying to eat them. The remaining energy that reaches them passes through their bodies, leaving the system. These top predators, then become the critical, the climax actors in the final act of this ecological play. It is through them this energy, initially captured by plants from the sun, flows, completing its run, its final curtain call. However, it is a never ending final call, a never ending play as new energy continues moving up, new prey, new predators, new actors, providing life, vitality, diversity to the stage of the ecosystem, the play of life.
What happens if these top actors are missing? Can the play go on? Can a system fine tuned over evolutionary time whose function depends on each part being connected, continue to work in the absence of its climax actors? We have ample evidence that suggests not. Predators in general and large ones in particular, have always bore the brunt of humans’ dislike and scorn. Viewed as villains rather than stars in the play of life, they have always been the first to be removed from the stage. This has happened not only in the Eastern forests but in most ecosystems in the world. What has happened in these ecological plays when the top actors have been removed? Without predators, the energy flow become blocked and can no longer flow upward. The blockage of this energy flow, as with the blockage of a river or of any flow-through system, the flow backs up, disrupting the system, the ecosystem. It concentrates in the form of excess numbers of consumers, normally prey for higher levels, and it builds up. Like a volcano building up pressure and eventually exploding in a series of violent eruptions, destroying the mountain, increasing consumers destroy the ecosystem. In Yellowstone National Park, removal of the Wolf led to an over population of Elk, leading to losses of plant species Elk preferred, to losses of other species dependent on these plants, to eventual losses of Elk who starved and died under their own population weight. Yellowstone changed from a smooth flowing river of energy to one of fits and starts, of energy blockage, a system of violent cycles. This pattern has repeated itself many times over, the Kaibab plateau after the removal of Cougars, the Moose on Isle Royale, introduced without their predator, the Wolf. To remove the top predators in these ecosystems was an ecological crime, committing these systems to a slow agonizing death.
How about the Appalachian forests? Is the cast of ecological players complete? Unfortunately, the East is also missing its star performers, Wolves and Cougars, having been long killed out by our well-meaning but misguided ancestors. All that remains are the ghosts of these past performers, apparitions that seemingly appear periodically but are of little substance. Regardless of all these ghostly sightings, real or otherwise, the cold fact remains, the Wolf and Cougar are ecologically extinct in the Appalachians. In the absence of these actors, the stage is set for a different script. Without Wolves and Cougars, their main prey, White-tailed Deer, have returned with a vengeance, in many eastern states numbering in hundreds of thousands to millions of animals. Each of these individuals ravenously eat around 1,500 pounds of plants per year. As a result, the eastern ecosystems are time bombs waiting to explode. Some have already; after years of excessively high deer densities, forest flowers and animals dependent on them are disappearing. As importantly, tree seedlings, the forest of the future, are also vanishing under the constant chewing of millions of deer. The ecological fabric of the Appalachian ecosystem is unweaving before our very eyes. What we see in the verdant, seemingly vibrant forests is a façade hiding a rapidly decaying stage of life, burdened by too many prima donnas. What we see is not an endless play of life but a short-lived tragedy doomed to failure.
The fact is clear, the Appalachian play is missing its star performers and an ecological disaster is unfolding on the stage. Can the ending of this play be changed by bringing back the stars? Can it be as simple as that? Scientifically, the answer is a resounding yes. However, before society agrees, many questions need to be answered. The first of which is: can Wolves and Cougars still survive on the modern stage that is the Appalachians of today? If so, what are some of the dangers, if any, of them coming back. After all, aren’t they large and dangerous animals??? If we agree that they should come back, how do we as a society help them back? These and many more questions I hope to address in future posts to this blog.
John Laundré
I was born and raised in the Midwest (Wisconsin) and received my bachelors and masters degrees there. I received my PhD from Idaho State University in 1979. Since then, I have been working in large mammal predator-prey ecology for over 30 years and have studied predators and their prey in the western U.S. and northern Mexico. My experience includes working with cougars, wolves, coyotes, bobcats, deer, elk, bison, and bighorn sheep. I have conducted one of the longest (17 years) studies of cougar ecology and behavior to date and have published over 15 scientific articles both on this work and work conducted in Mexico. I am the originator of the concept of the landscape of fear that proposed that fear of prey for their predators drives many, if not all ecological processes. The one important aspect of this concept is that predators become instrumental in maintaining the balance between prey species and their habitat, not so much by killing their prey but affecting how they use the landscape. I am the author of the newly published book, Phantoms of the Prairie: The Return of Cougars to the Midwest that looks at the phenomenon of cougars actually moving back into the Great Plains region of the U.S. I am currently living in Upstate New York in Oswego where I am an adjunct faculty member at the SUNY Oswego and also active in issues concerning cougars in the Northeast. I am the vice president of the Cougar Rewilding Foundation whose goal is the eventual re-establishment of viable cougar populations in the Eastern U.S.
Want to Learn More?
Laundré JW (2010). Behavioral response races, predator-prey shell games, ecology of fear, and patch use of pumas and their ungulate prey. Ecology, 91 (10), 2995-3007 PMID: 21058559
RIPPLE, W., & BESCHTA, R. (2004). Wolves and the Ecology of Fear: Can Predation Risk Structure Ecosystems? BioScience, 54 (8) DOI: 10.1641/0006-3568(2004)054[0755:WATEOF]2.0.CO;2
Predator and Prey, a Delicate Dance
By JOHN A. VUCETICH, MICHAEL P. NELSON and ROLF O. PETERSON
IN Lake Superior lies a remote island, Isle Royale National Park, 134,000 acres of boreal and hardwood forests where a life-or-death struggle between wolves and moose has been the subject of the world’s longest study of predators and their prey, now in its 55th year.
Joohee Yoon
Moose first appeared on this Michigan island in the first decade of the 20th century, apparently by swimming from the mainland. With no predator to challenge them, the moose population surged (interspersed by two crashes, from starvation) and devastated the island’s vegetation in search of food. Then wolves arrived in the late 1940s by crossing an ice bridge from Canada, and began to bring balance to an ecosystem that had lurched out of control.
Today, moose are essentially the only supply of food for the wolves, and wolf predation is the most typical cause of death for moose. But the wolf population is small, and decades of inbreeding have taken their toll. The ice bridges that allow mainland wolves to infuse the island’s wolf population with new genes form far less frequently because of our warming climate. With the number of wolves reduced to little more than a handful, they face the prospect of extinction.
The National Park Service is expected to decide this fall whether to save the Isle Royale wolves — a decision that will test our ideas about wilderness and our relationship with nature. This is because the park is also a federally designated wilderness area, where, under federal law, “the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.” If we intervene to save the wolf, will we be undermining the very idea of not meddling that, since the passage of the Wilderness Act in 1964, has been the guiding principle behind the protection of 109 million acres of federal land?
The park service has three options: conserve Isle Royale’s wolf population by taking new wolves to the island to mitigate inbreeding, an action known as genetic rescue; reintroduce wolves to the island, if and when they go extinct; or do nothing, even if the wolves disappear.
As the lead researchers in the study of wolves and moose, we favor conservation or reintroduction. But more important than our view is the reasoning behind it.
Wilderness is conventionally viewed as a place where nature should be allowed to take its course, free of human interference. This is essentially the principle of nonintervention that has guided America’s relationship with wilderness areas for roughly 50 years.
Importantly, two of the architects of modern-day thinking about wilderness, the wildlife biologists Aldo Leopold and Adolph Murie, supported the idea of introducing wolves to Isle Royale in the 1940s — to conserve a habitat being overrun by moose — before wolves had arrived on their own.
The principle of nonintervention touches on fundamental conservation wisdom. But we find ourselves in a world where the welfare of humans and the biosphere faces considerable threats — climate change, invasive species and altered biogeochemical cycles, to name a few. Where no place on the planet is untouched by humans, faith in nonintervention makes little sense. We have already altered nature’s course everywhere. Our future relationship with nature will be more complicated. Stepping in will sometimes be wise, but not always. Navigating that complexity without hubris will be a great challenge.
These realizations have led a number of environmental scholars to consider new visions for the meaning of wilderness. One is of a place where concern for ecosystem health is paramount, even if human action is required to maintain it.
The future health of Isle Royale will be judged against one of the most important findings in conservation science: that a healthy ecosystem depends critically on the presence of top predators like wolves when large herbivores, like moose, are present. Without top predators, prey tend to become overabundant and decimate plants and trees that many species of birds, mammals and insects depend on. Top predators maintain the diversity of rare plants that would otherwise be eaten, and of rare insects that depend on those plants. The loss of top predators may disturb the nutrient cycling of entire ecosystems. In addition, predators improve the health of prey populations by weeding out the weakest individuals. Also, wolves are a boon to foxes, eagles, ravens and other species that scavenge from carcasses that wolves provide.
Given that moose will remain on Isle Royale for the foreseeable future, the National Park Service should initiate a genetic rescue by introducing new wolves to the island.
In a world increasingly out of balance, Isle Royale National Park is a place with all its parts, where humans kill neither wolves nor moose, nor log its forests. Places like it, where we can witness beauty while reflecting on how to preserve it, have become all too rare.
John A. Vucetich is a population biologist, and Rolf O. Peterson is a wildlife ecologist, both at Michigan Tech. Michael P. Nelson is an environmental ethicist at Oregon State University.
Source: http://www.nytimes.com/2013/05/09/opinion/save-the-wolves-of-isle-royale-national-park.html?
Between Thorn Bushes and Claws 
