It’s never too late to publish

In 2005 I undertook my very first field study assessing whether a one-off control program could reduce red fox density on an agricultural property in NSW. Despite my efforts of removing 47 foxes in 12 nights, the control program only reduced the fox population by 1 fox per square kilometre. This was my first introduction to the difficulties of managing invasive species and it provided my first lesson on how not to control foxes! The work is now finally published and hopefully the paper demonstrates that isolated and uncoordinated efforts to control foxes are not effective at reducing fox density. Below is a copy of the abstract. Click HERE for a link to the paper.

As a side note, an additional component of the project involved radio-tracking foxes that I had caught and released with VHF collars. Back in those days GPS collars were not available. I spent many late nights tracking the foxes and I thought a few people might appreciate the picture below of the Toyota Landcruiser I modified to allow for radio-tracking via a large antennae that was installed in the tray.




Abstract: Uncoordinated and isolated control programs are often used by land managers, property owners and recreational hunters to control numbers and reduce the impacts of European red foxes (Vulpes vulpes). However, decades of such attempts to eradicate this significant agricultural and biodiversity pest in many countries have failed. We investigated the effectiveness of an uncoordinated and isolated shooting program to determine if it caused any change in red fox population density. We also determined whether shooting is more cost effective than poison baiting for fox control. First, we estimated the density of foxes on an agricultural study property using distance sampling and rates of bait uptake before and after a control program. Second, we estimated the costs associated with undertaking the control program and compared it to the estimated costs of undertaking poison baiting. Prior to control, we estimated a density of 4.18 foxes per square kilometre. After the control exercise, which removed 47 individuals in 12 nights, we estimated a density of 3.26 foxes per square kilometre. Our results provide evidence that one-off control programs are not effective in greatly reducing red fox density, even if the control effort is intensive. Where large-scale control programs cannot be coordinated, isolated programs should therefore involve follow-up campaigns to reduce population recovery. On a local scale, combinations of shooting and baiting may also provide maximum control impact at minimal cost.


Link to latest radio interview on wolves

Perhaps the most mystic – and most feared – wildlife in Canada, wolves are making a comeback. Throughout the western United States, wolf populations are beginning to re-emerge after a courageous plan to reintroduce them to Yellowstone National Park in the 1990s. But along with their reintroduction has come ongoing fear, paranoia from ranchers and the happy trigger fingers of hunters and trappers.

Add that to the ongoing persecution of wolves in Canada and the species is by no means free of their one-time endangered status.

But this has also created an unique and historic opportunity to study wolves and how they affect ecosystems. Two recent studies have identified and are extrapolating what is becoming known as The Wolf Effect.

We’ll hear from two leading scientists who have examined this phenomenon; first is Dr. Thomas Newsome, who has worked with a team that is exploring how wolf populations affect the populations of foxes and coyotes. Then we’ll be joined by Dr. Mark Elbroch, who is part of one of the longest-standing cougar studies in North America and has fascinating details on how wolves are impacting cougar populations and territory selection.

To listen to this week’s episode, download the MP3 or use the direct link

Data Source:


What is the “Wolf Effect”?

Find out more about the “wolf effect” by listening to my recent radio interview on ABC 666 with Alex Sloan

20 June 2014 , 12:46 PM by Farz Edraki

Recent animal trapping records show a strong ‘wolf effect’ across North America.

But what is the ‘wolf effect’?

Click here to listen: Wolf Effect


Media picks up our wolf-coyote-fox paper

We have had a great response from the media so far this week. Here are some of the articles that have been written on our recently published wolf-coyote-fox paper in the Journal of Animal Ecology:

Reintroducing wolves is only effective at large spatial scales (Conservation Magazine)

Bring back the wolf – everywhere (Takepart by Richard Conniff)

What is the wolf effect (ABC News)

Bring back the wolf – everywhere (Strange Behaviors by Richard Conniff)

Wolves have an effect on coyotes, foxes across North America (Red Orbit)

Animal trapping records reveal strong wolf effect across North America (Oregon State University)

‘Wolf effect’ key in determining fox-coyote ratio, study says (CBC News)

Fox and coyote trapping records reveal the major impact of wolves across North America (Science World Report)

What American wolves can teach us about Australian dingoes (The Conversation)

The fox and the wolf: an unlikely duo (Nature World News)

Red fox decline linked to coyote (Herald News)

Animal trapping records reveal strong wolf effect across North America (Salem News)

Trapping records reveal strong wolf effect across North America (Cattle Network)

Old fur trade records show predator has ripple effect on ecosystems (EENews)

Animal trapping records reveal strong wolf effect across North America (Phys.Org)

Animal trapping records reveal strong wolf effect across North America (E! Science News)

Animal trapping records reveal strong wolf effect across North America (Science Codex)

What American wolves can teach us about Australian dingoes

New article just published in The Conversation

The results of our wolf-coyote-fox cascade paper are now summarised in The Conversation.

Click here for a direct link to the article





Early view version of wolf-coyote-fox cascade paper now available


(The study species from left to right: a wolf, coyote and red fox. Photo credits: wolf – Doug McLaughlin, coyote – Shawn McCready cc @flickr, red fox – Kelly Colgan Azar cc @flickr)

The Journal of Animal Ecology has now released my latest paper in the ‘accepted unedited articles section’. Below is a copy of the abstract.

Paper title: A continental scale trophic cascade from wolves through coyotes to foxes

By: Thomas M Newsome and William J Ripple


  1. Top-down processes, via the direct and indirect effects of interspecific competitive killing (no consumption of the kill) or intraguild predation (consumption of the kill), can potentially influence the spatial distribution of terrestrial predators, but few studies have demonstrated the phenomenon at a continental scale.
  2. For example, in North America, grey wolves (Canis lupus) are known to kill coyotes (Canis latrans), and coyotes, in turn, may kill foxes (Vulpes spp.), but the spatial effects of these competitive interactions at large scales are unknown.
  3. Here, we analyse fur return data across eight jurisdictions in North America to test whether the presence or absence of wolves has caused a continent-wide shift in coyote and red fox (Vulpes vulpes) density.
  4. Our results support the existence of a continental scale cascade whereby coyotes outnumber red foxes in areas where wolves have been extirpated by humans, whereas red foxes outnumber coyotes in areas where wolves are present. However, for a distance of up to 200 km on the edge of wolf distribution, there is a transition zone where the effects of top-down control are weakened, possibly due to the rapid dispersal and reinvasion capabilities of coyotes into areas where wolves are sporadically distributed or at low densities.
  5. Our results have implications for understanding how the restoration of wolf populations across North America could potentially affect co-occurring predators and prey. We conclude that large carnivores may need to occupy large continuous areas to facilitate among-carnivore cascades and that studies of small areas may not be indicative of the effects of top-down mesopredator control.


Animal trapping records reveal strong wolf effect across North America


(The study species from left to right: a wolf, coyote and red fox. Photo credits: wolf – Doug McLaughlin, coyote – Shawn McCready cc @flickr, red fox – Kelly Colgan Azar cc @flickr)

Oregon State University Press Release

This story is also available here

CORVALLIS, Ore. — Scientists have used coyote and red fox fur trapping records across North America to show 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. “They were historically located in the middle and western United States, but they dispersed all the way to Alaska in the early 1900’s 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 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,” he added. “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.


Get every new post delivered to your Inbox.

Join 154 other followers