Yellowstone ecosystems - reintroduction of wolves

Wolves spur rebirth of Yellowstone ecosystems
By Summit Voice

SUMMIT COUNTY — The reintroduction of wolves has resulted in profound ecoystem changes in the Greater Yellowstone region.

For the first time in 70 years, the over-browsing of young aspen and willow trees has diminished. Trees and shrubs are recovering along some streams, providing improved habitat for beaver and fish.

“Yellowstone increasingly looks like a different place,” said William Ripple, a professor in the Department of Forest Ecosystems and Society at Oregon State University, and lead author of a recent study documenting some of the changes.

“These are still the early stages of recovery, and some of this may still take decades,” Ripple said. “But trees and shrubs are starting to come back and beaver numbers are increasing. The signs are very encouraging.”

The findings of this report are based on a recent analysis done by OSU researchers and a review of other studies. They were published recently in Biological Conservation, a professional journal. They outline an ecosystem renaissance that has taken place since wolves were restored toYellowstone after being extirpated in the 1920s

Among the observations in this report:
•Since their reintroduction in 1995-96, the wolf population generally increased until 2003, forcing changes in both elk numbers and behavior due to what researchers call the “ecology of fear.”

•The northern range elk populations decreased from more than 15,000 individuals in the early 1990s to about 6,000 last year, and remaining elk now have different patterns of movement, vigilance, and other traits.

•By 2006, some aspen trees had grown tall enough they were no longer susceptible to browsing by elk, and cottonwood and willow were also beginning to return in places.

•Improved willow growth is providing habitat that allows for a greater diversity and abundance of songbirds such as the common yellowthroat, warbling vireo and song sparrow.

•The number of beaver colonies in the same area increased from one in 1996 to 12 in 2009, with positive impacts on fish habitat.

•Increases in beaver populations have strong implications for riparian hydrology and biodiversity – Wyoming streams with beaver ponds have been found to have 75 times more abundant waterfowl than those without.

•The coyote population decreased with the increase in wolf numbers, potentially allowing more small mammals that provide food for other avian and mammalian predators, such as red foxes, ravens and bald eagles.

Read more here ...

The wolverines that float on snow

Eight-year tracking programme reveals more about mysterious species

December 2011: Born during February in snow-caves at 9,000 feet on the north slope of craggy peaks in the Rocky Mountains, Yellowstone's wolverines are tough.

Now experts at the Wildlife Conservation Society (WCS) are revealing more about this mysterious and awe-inspiring species.

Eight years of capturing and radio-tracking the elusive wolverine revealed that adults live year-round in the high mountains, near the alpine tree-line, and inhabit some of the west's most remote and rugged terrain. Amazingly, the home range of an individual male can more than 500 square miles.

The winter endurance athletes of the animal world
‘Not only do they use an area even larger than a grizzly bear does,' said Kurt Alt, a coauthor with Montana Department of Fish, Wildlife and Parks, ‘they cover their territory on a fairly regular basis to scent mark it and defend it from other wolverines.'

The wolverine's capability for movement is stunning. Their large feet allow them to float on top of deep snow, and they were documented making winter traverses from one side of the massive Teton Range in Wyoming to the other in just a few hours.

‘They are the winter endurance athletes of the animal world,' said Steve Cain of the National Park Service. ‘We were impressed by their constant movements across large areas of snow-covered and incredibly rugged terrain.'

But covering this terrain comes with its risks, as two of the radio-collared wolverines were killed in avalanches.

One wolverine travelled more than 500 miles
Another wolverine travelled more than 500 miles from near Grand Teton National Park in northwest Wyoming to Rocky Mountain National Park in Colorado. This was the first documented wolverine in Colorado in almost a century. Other young wolverines regularly moved 100 miles or more searching for their own territory.

While bears are hibernating and most ungulates and their predators have moved to low elevation wintering ranges, the wolverine patrols a vast, frozen territory, looking for scraps of meat that they cache under boulders and snow.'

‘We learned that wolverines are adapted to eke out a living in very harsh conditions,' said Robert Inman, conservationist for the WCS. ‘As a result, they naturally exist in low numbers and reproduce slowly.'

The wolverine's reputation as a fierce competitor was also affirmed during the study. One individual challenged a bear probably ten times his size over an elk carcass.


http://www.wildlifeextra.com/go/news/wolverine-yellowstone.html

Another Bear attack in Yellowstone

A bear attack caused the death of a hiker whose body was found on a trail in Yellowstone National Park, officials confirmed Monday.

The body of John Wallace, 59, was discovered Friday by two hikers along the Mary Mountain Trail, an area of the park that had been closed to hikers, according to park services.

Rangers discovered signs of grizzly bear activity, including tracks and scat, or bear droppings, in a park campground where they believe Wallace pitched a tent on Wednesday, the park said in a news release.

Autopsy results concluded that Wallace, a Michigan resident, died from traumatic injuries he received after being mauled by a bear. It's the second fatal attack in Yellowstone National Park this summer, said Park Superintendent Dan Wenk.

Just last month, a 57-year-old California man was killed by a bear within the same 10-mile area of the park, Wenk said.

Park managers determined that man was killed by a bear protecting its cubs. Despite the close proximity of the latest attack, the officials do not think the same bear is responsible for Wallace's death because no evidence of cubs was found at the scene.

DNA tests on hair samples from the site will be performed to confirm suspicions that a different bear was involved in the second attack, Wenk said.

Over the past 25 years, Yellowstone has averaged 1 or 2 encounters a year that resulted in injuries, Wenk said.

Prior to this summer's attacks, the last fatal bear mauling was in 1986, he said.
http://www.cnn.com/2011/US/08/29/wyoming.bear.attack/index.html?hpt=hp_t2

Grizzly Bear Kills Hiker Who Disturbed Cubs

A female grizzly bear has killed a man hiking with his wife in Yellowstone National Park after the couple surprised the animal and her cubs.


The attack happened about a mile and a half from the start of the popular Wapiti Lake trail.

Another group of hikers nearby who heard the victim's wife screaming for help called park rangers.

A National Park Service statement said the couple had inadvertently surprised the mother grizzly and her cubs, and in "an attempt to defend a perceived threat to her cubs, the bear attacked and fatally wounded the man".

Grizzly bears can weigh up to 1,500lb and despite their size, they can run at speeds of up to 35mph, according to the US Fish and Wildlife Service.

The bears tend to avoid humans but can be extremely aggressive if they perceive a threat to their young.

There are warning signs about grizzlies throughout the national park and Wednesday's attack took place in an area where bear sightings are common.

The victim's identity has not been released while his family is informed.
Park officials said the animals involved have not been captured and rangers do not have enough information yet to determine what measures they might take.

But park spokeswoman Linda Miller said the mother bear behaved normally in defending her cubs and would not be killed as a result of her actions.

Bears found to have repeated run-ins with park visitors are, however, sometimes relocated.

"If we have an aggressive bear that continually poses a threat to human safety, then we work to remove it from the ecosystem," Yellowstone spokesman Al Nash said.

Attacks by bears are extremely rare and the mauling marks the first fatal bear attack in the park since 1986, the Park Service said.

But a mother grizzly killed one man and injured two other people in an unusual night-time attack on sleeping campers just outside Yellowstone in Montana last July.

The animal involved was later trapped and destroyed because the attacks were considered to be unprovoked and predatory.
http://uk.news.yahoo.com/grizzly-bear-kills-hiker-disturbed-cubs-080643772.html