Search This Blog

Thursday, February 4, 2010

Melting snowpack thins wolverine population: study

By David Wylie,

"The ferocious wolverine — strong enough to kill prey as large as a moose — may not be tough enough to survive climate change."
"New research published in the journal Population Ecology suggests that as the wolverine's snowy habitat across northwestern Canada melts, the hardy and elusive creature's population thins."
"The general trend is that the faster the snowpack is declining, the more it's declining, the worse off it seems to be for the wolverines," said wildlife biologist Jedediah Brodie of the University of Montana. "Every year, it's becoming more and more clear that climate change is having important impacts on eco-systems, on wildlife species.
"Brodie took interest in wolverines while studying how declining snowpacks in Yellowstone National Park affect elk. He started thinking about whether snowpacks also impact other species."

"Brodie and Pennsylvania State University biologist Eric Post decided to research first whether the snowpack across Canada's four western provinces and three territories was in decline — which it was — then study how that impacted the wolverine, a creature perfectly adapted to snowy conditions. The small bearlike creatures have thick, frost-resistant fur and large paws perfect for padding across snow."

"The researchers looked at the number of wolverines caught by trappers from 1970-2004 and compared it with the rate at which the snowpack shrunk. They found "intriguing evidence of a link," he said.

"Brodie said he's not sure why the diminishing snowpack may affect the wolverine populations, but he has some ideas."

"Within its range, the wolverine occupies many different kinds of habitats. Wolverines generally prefer remote areas, far away from humans and their developments. However, the specific characteristics of the wilderness that the wolverine depends upon are not yet known. Labrador and Quebec, for example, have not been recolonized by wolverines, despite the abundance of caribou and undisturbed habitat. This lack of knowledge about wolverine habitat makes it difficult for wildlife managers to manage the species and protect its habitat."

"Studies are expensive and difficult to conduct because of wolverines’ large home ranges and low densities. It is not surprising that we are still learning about the biology and behaviour of this species. Some of the mysteries have been dispelled with the help of studies in Alaska, Montana, British Columbia, Yukon, and Nunavut of wolverines equipped with collars that allow their movements to be monitored using satellites."
"The home range of an adult wolverine extends from less than 100 km2 for females to over 1 000 km2for males. These home ranges are the largest reported for a carnivore of this size, and in many areas they rival the home ranges of bears, wolves, and cougars. The size of the home range varies depending on the availability of food and how it is distributed across the landscape — the more food there is, the smaller the home range needs to be."

"The density of wolverines ranges from one individual per 40 km2 to one per 800 km2. Those regions that have the most different kinds of habitat and prey, particularly those that include large ungulates, or animals with hooves, contain the most wolverines. The mountainous and forested areas of British Columbia and Yukon have the highest densities, although these numbers are still low compared with the densities of other carnivores. Densities of wolverines in Manitoba and Ontario are lower. The rarity of wolverines becomes readily apparent when their density is compared with the density of other solitary carnivores: one coyote per 0.5 to 10 km2 and one grizzly bear per 1.5 to 260 km2. "

Wolverines are not abundant anywhere, even where they do well.

"There are two main reasons why wolverine populations disappeared from parts of North America. The first is that wolverines are scavengers—which means they feed on carrion, or dead animals—and are attracted to bait. Because the wolverines damaged traplines, early trappers used any means to kill them, including poison. The extensive wolf poisoning programs that occurred throughout Canada beginning in the late 1700s also killed many wolverines."

"The second, and more important, reason for the decline of wolverine populations is that wolverines have a low resiliency because of their low densities and low reproduction, or the number of young that are successfully produced and raised. This means that wolverine populations have a difficult time rebounding once their numbers have been lowered by either nature or human-influenced factors."

"The wolverine is a carnivore, or flesh eater. It is more of a scavenger than a hunter, and is usually dependent on other carnivores, such as wolves, to kill the animals for it to eat. Leftovers from a wolf kill can be considerable. The wolverine has been known to carry away moose carcasses and caribou heads. Because of its great dependence on carrion, or dead flesh, from large mammal kills, the wolverine needs to be able to survive long periods without food. It will revisit old kills to consume frozen bones and pelts when it cannot find other food."

Distribution of Wolverine
"The wolverine is found throughout all northern regions of the globe. Wolverines are not abundant anywhere, even where they do well. The species is known for a large home range and low density, which is a measure of its numbers. The Committee on the Status of Endangered Wildlife in Canada considers wolverines found west of Hudson Bay to be of “special concern” and the eastern population, found in Quebec and Labrador, to be “endangered.”

"A portion of the wolverine’s historical range has been lost. Wolverines have also disappeared from areas with relatively intact habitats. Eastern Canada and the western United States have been particularly hard hit. Wolverines disappeared most rapidly at the edges of their distribution and in Eastern Canada. We do not know if any wolverines still occur in Eastern Canada, although Labrador and Quebec are still considered part of the current distribution. Similarly, whether wolverines still occur on Vancouver Island is unknown."

"Since ungulates are not always available, wolverines must have a diversity of prey in their diet to survive. Female wolverines with young, or “kits,” rely on small mammals, such as marmots and ground squirrels. As the movements of family groups are restricted, food must be found in a smaller area. Snowshoe hares, especially when they are particularly abundant, are an important food source for all wolverines. Wolverines hide excess food by burying it or stashing it in rock crevices or in trees."

"Scavenging is a difficult way to survive. Many young, inexperienced wolverines and very old wolverines die from starvation, even if food is abundant. Transients, typically young adults passing through the territory, have a higher mortality rate than residents, because they do not benefit from hunting in a familiar home range."

"The wolverine pelt remains one of the most prized furs because of its beauty and because frost brushes off easily. The Inuit and Dene of northern Canada use wolverine fur as trim and lining for their clothing, such as parkas, mitts, and moccasins. Over 80 percent of all wolverine pelts sold in Canada—about 400 to 600 each year—come from the Northwest Territories, Nunavut, Yukon, and British Columbia. Wolverine fur is consistently high in value: a well-handled and prime pelt sells for an average of $400."

"Roads that permit human access to wolverine habitat can be detrimental to wolverine populations, especially if the animals are also killed by trapping or hunting. In areas where logging occurs, wolverines may use the forested corridors adjacent to roads to get to other parts of their home ranges. This makes them vulnerable to trappers who use the same roads to set their traps. Major roads, like the Trans-Canada Highway, can also keep wolverines from reaching important parts of their habitat."

"Denning females are sensitive to disturbance, particularly human activity. Even the presence of careful researchers has caused wolverines to abandon their dens. The increasing use of snowmobiles and skiing in the vicinity of wolverine dens, such as in subalpine mountainous regions, can harm wolverine populations. However, in tundra areas, female wolverines have tolerated human activity without abandoning their dens."

"A number of zoological organizations and individuals have been successful in raising wolverines in captivity. Researchers have learned much about wolverine behaviour from studying these captive animals. It has been suggested that wolverines raised in captivity could be used in reintroductions, where wolverines are moved to a new region in order to increase or augment existing populations or assist in the recovery of endangered populations. The success of wolverine reintroductions depends on many factors. There must be a sufficient supply of animals, and reintroduced animals must originate from the same habitat, environmental conditions, and genetic stock (to protect those characteristics that have allowed them to adapt to those environmental conditions) as the animals they are joining."

"A recovery plan is being written to examine the options for the survival of the eastern Canadian wolverine population and the measures necessary to achieve its recovery. In other regions of Canada, trapping can be a concern in areas where safe places or refuges for wolverines need to be maintained, especially if an increase in population numbers is required. Trapping must be excluded over a very large area to protect a sufficient number of resident wolverines. Protection of denning habitat from human disturbance may also be critical for wolverine survival."

"Wolverines are subject to the same habitat threats that affect other large carnivores in Canada, like the grizzly bear. The wolverine does not appear to thrive in habitats that have been permanently altered by land-based activities, such as agriculture, urban and industrial development, and human settlement. The problem does not appear to be the actual loss of habitat or the presence of humans. Instead, the problem seems to be the breaking up, or fragmentation, of the wolverine habitat, as well as the increased human access to the habitat. Studies of wolverine ecology do not suggest that wolverines cannot co-exist with certain land-use activities, such as forestry and mining. However, where such activities occur, especially if they are coupled with trapping, low-density wolverine populations can have a difficult time surviving or growing. Even higher-density populations, such as those in the mountainous areas of British Columbia, can be negatively affected by human access and trapping."

It would be extremely troubling to  a nature lover such as myself, if the wolverine became extinct on this planet.I have been fascinated by this animal species from a young age, and if the wolverine disappears from the earth, then humans have to take much of the blame for this, due to our willingness to destroy the habitat of the wolverine and due to our seemly endless desire to overpopulate the planet with our species! 

No comments:

Visit GM Alexandra Kosteniuk's Women's Chess Blog:Please click on the image below:

Visit GM Alexandra Kosteniuk's Women's Chess Blog:Please click on the image below:
Chess needs more women and girl participants and administrators!

Thoughts worth thinking about

"Our subconscious minds have no sense of humor, play no jokes and cannot tell the difference between reality and an imagined thought or image. What we continually think about eventually will manifest in our lives."-Sidney Madwed

Laws alone can not secure freedom of expression; in order that every woman and man present their views without penalty, there must be spirit of tolerance in the entire population.- Albert Einstein Too often we underestimate the power of a touch, a smile, a kind word, a listening ear, an honest compliment, or the smallest act of caring, all of which have the potential to turn a life around. - Leo Buscaglia

A person's true wealth is the good he or she does in the world. - Mohammed

Our task must be to free ourselves... by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty. -Albert Einstein

The best way to find yourself, is to lose yourself in the service of others. - Ghandi

The unselfish effort to bring cheer to others will be the beginning of a happier life for ourselves. - Helen Keller

Aim for success, not perfection. Never give up your right to be wrong, because then you will lose the ability to learn new things and move forward with your life. Remember that fear always lurks behind perfectionism. Confronting your fears and allowing yourself the right to be human can, paradoxically, make yourself a happier and more productive person. - Dr. David M. Burns

Life is as dear to a mute creature as it is to man. Just as one wants happiness and fears pain, just as one wants to live and not die, so do other creatures. -His Holiness The Dalai Lama

Mankind's true moral test, its fundamental test (which lies deeply buried from view), consists of its attitude towards those who are at its mercy: animals. And in this respect mankind has suffered a fundamental debacle, a debacle so fundamental that all others stem from it. -

Milan Kundera, The Unbearable Lightness of Being

The worst sin towards our fellow creatures is not to hate them, but to be indifferent to them. That's the essence of inhumanity. -George Bernard Shaw

Ego's trick is to make us lose sight of our interdependence. That kind of ego-thought gives us a perfect justification to look out only for ourselves. But that is far from the truth. In reality we all depend on each other and we have to help each other. The husband has to help his wife, the wife has to help the husband, the mother has to help her children, and the children are supposed to help the parents too, whether they want to or not.-Gehlek Rinpoche Source: "The Best Buddhist Writing 2005 pg. 165

The hostile attitude of conquering nature ignores the basic interdependence of all things and events---that the world beyond the skin is actually an extension of our own bodies---and will end in destroying the very environment from which we emerge and upon which our whole life depends.