Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Animal trapping records reveal strong wolf effect across North America

16.06.2014

Scientists have used coyote and red fox fur trapping records across North America to document how the presence of wolves influences the balance of smaller predators further down the food chain.

From Alaska and Yukon to Nova Scotia and Maine, the researchers have demonstrated that a "wolf effect" exists, favoring red foxes where wolves are present and coyotes where wolves are absent.

This effect requires that enough wolves be present to suppress coyotes over a wide area. Fur trapping records from Saskatchewan and Manitoba reveal that where wolves are absent in the southern agricultural regions of each province, coyotes outnumber foxes on average by 3-to-1. However, where wolves are abundant in the north, the balance swings dramatically in favor of foxes on average by 4-to-1 and at an extreme of 500-to-1 at one site.

In between is a 200-kilometer (124-mile) transition zone where too few wolves are present to tip the balance between coyotes and foxes.

The results of the study by Thomas Newsome and William Ripple in the Oregon State University Department of Forest Ecosystems and Society were published today in the Journal of Animal Ecology by the British Ecological Society.

"As wolves were extirpated across the southern half of North America, coyotes dramatically expanded their range," said Newsome, a post-doctoral researcher at Oregon State. "They were historically located in the middle and western United States, but they dispersed all the way to Alaska in the early 1900s and to New Brunswick and Maine by the 1970s."

"So essentially coyotes have been dispersing into wolf and red-fox range in the north but also into areas where wolves are absent but red fox are present in the East," Newsome added.

Newsome came to the United States on a Fulbright scholarship from Australia where he earned a Ph.D. from the University of Sydney and specialized in the study of dingoes – that continent's top predator. There's a debate among Australians, he said, about the potential role of dingoes in suppressing introduced pests that have already decimated wildlife there.

"Over the last 200 years, Australia has had the highest extinction rate in the world," Newsome said. "The debate is about whether the dingo can provide positive ecological benefits. Where dingoes have been removed, the impacts of introduced red foxes and feral cats have been quite severe on native fauna."

Dingoes are managed as a pest in New South Wales, the country's most populous state. To reduce dingo predation in the livestock industry, Australia also maintains the world's longest fence, which runs for 5,500 kilometers (3,400 miles) in an attempt to exclude dingoes from almost a quarter of the continent.

In North America, the effect of wolves on coyotes and red foxes provides a natural case study that can be instructive for Australians. "Australians can learn a lot from how wolves are managed in North America, and Americans can learn from the ecological role of the dingo," Newsome said.

As coyotes have expanded in North America, they have become a major cause of concern for the livestock industry. In the United States in 2004, researchers estimated annual losses due to coyote predation on sheep and cattle at $40 million. To reduce those damages, the Wildlife Service of the U.S. Department of Agriculture has a program to reduce coyote numbers, an effort that has drawn criticism from conservation groups.

In reviewing the fur trapping data from two U.S. and six Canadian jurisdictions, Newsome and Ripple eliminated potential sources of bias such as records from fur farms that raise foxes. The fur prices of coyotes and red foxes are also strongly correlated, and the two species occupy much of the same types of habitat, so they are equally likely to be targeted and caught in hunters' traps.

"This study gives us a whole other avenue to understand the ecological effects of wolves on landscapes and animal communities," said Ripple. He has studied the influence of carnivores on their prey — such as deer and elk — and on vegetation from aspen trees to willows. He and his colleagues have shown that the removal of top predators can cause dramatic shifts within ecosystems.

Wolves are naturally recolonizing many areas of the United States following their reintroduction into Yellowstone National Park and surrounding areas in 1995. Scientists are studying wolf interactions with other species, and in particular, there is interest in determining whether recolonizing wolves will suppress coyote populations and have cascading effects on red foxes and other species.

###

Newsome received funding from the Australian-American Fulbright Commission and from the government and universities of New South Wales in Australia.

William Ripple | Eurek Alert!

Further reports about: Ecosystem Wales coyotes dingoes ecological livestock industry species

More articles from Ecology, The Environment and Conservation:

nachricht The oceans can’t take any more
03.07.2015 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Improved veterinary service for livestock is significant for leopard conservation
02.07.2015 | Georg-August-Universität Göttingen

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Viaducts with wind turbines, the new renewable energy source

Wind turbines could be installed under some of the biggest bridges on the road network to produce electricity. So it is confirmed by calculations carried out by a European researchers team, that have taken a viaduct in the Canary Islands as a reference. This concept could be applied in heavily built-up territories or natural areas with new constructions limitations.

The Juncal Viaduct, in Gran Canaria, has served as a reference for Spanish and British researchers to verify that the wind blowing between the pillars on this...

Im Focus: X-rays and electrons join forces to map catalytic reactions in real-time

New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions

A new technique pioneered at the U.S. Department of Energy's Brookhaven National Laboratory reveals atomic-scale changes during catalytic reactions in real...

Im Focus: Iron: A biological element?

Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and a half billion years ago.

Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and...

Im Focus: Thousands of Droplets for Diagnostics

Researchers develop new method enabling DNA molecules to be counted in just 30 minutes

A team of scientists including PhD student Friedrich Schuler from the Laboratory of MEMS Applications at the Department of Microsystems Engineering (IMTEK) of...

Im Focus: Bionic eye clinical trial results show long-term safety, efficacy vision-restoring implant

Patients using Argus II experienced significant improvement in visual function and quality of life

The three-year clinical trial results of the retinal implant popularly known as the "bionic eye," have proven the long-term efficacy, safety and reliability of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

World Conference on Regenerative Medicine: Abstract Submission has been extended to 24 June

16.06.2015 | Event News

MUSE hosting Europe’s largest science communication conference

11.06.2015 | Event News

 
Latest News

Siemens receives order for offshore wind power plant in Great Britain

03.07.2015 | Press release

'Déjà vu all over again:' Research shows 'mulch fungus' causes turfgrass disease

03.07.2015 | Agricultural and Forestry Science

Discovery points to a new path toward a universal flu vaccine

03.07.2015 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>