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Crowdfunding Wolf Research: The Impact of Wolves in the American West

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In collaboration with the University of Washington Predator Ecology Lab we are launching an online crowdfunding effort.

Led by Professor Aaron Wirsing, we hope to raise $12,000 US to fund radio collaring deer as part of an ongoing wolf study.

Our goal is to better understand how the return of these top predators to Washington may impact other carnivores, deer populations, and perhaps even plants.

To visit our campaign page and see our promotional video click here.

Please share our campaign page with as many friends as possible!

https://uw.useed.net/projects/129/home

Feeding the beasts

Polar Bears marked with numbers scavenge on the rubbish dump outside Churchill, Manitoba, Canada. (Photo credit B & C Alexander / Arcticphoto.com)

(Photo credit B & C Alexander / Arcticphoto.com)

Predators often have important roles in structuring ecosystems via their effects on each other and on prey populations. However, there is growing concern that the ecological roles of predators will be altered when they access readily available food provided by humans.

The key issue here is that 1 billion metric tonnes of food produced for humans each year is lost or wasted. Even in developing regions where food shortages exist, 44% of food produced for human consumption is lost in production, storage and transport, while consumers also waste large quantities of edible foods.

Frequently, this waste food is dumped or discarded so that it is easily accessed by wildlife, particularly in areas where there are high human densities or relaxed environmental policies. For example, large quantities of human food scraps are often discarded in unfenced rubbish dumps or left to rot around townships.

On top of this, in Africa and Asia alone, over 10 million tonnes of cattle carcasses are unused and discarded each year. High livestock mortality rates mean that millions of carcasses are left to rot in the field, while vast quantities of resource subsidies are available as crops. Urban settlements also continue to expand rapidly, adding to the expanses of modified landscapes where resource availability is regulated by human activities.

Dingoes scavenge at a waste facility

A predator using a resource subsidy: dingoes scavenging at a rubbish dump

In a recent paper published in Global Ecology and Biogeography, we quantified the ecological effects of providing resource subsidies to terrestrial mammalian predators (greater than 1 kg in body size) by reviewing published studies on the topic across the globe.

Overall, our review included data from 129 published studies. Seventy percent of the studies were published after 2000, indicating that predator access to human-provided foods is an emerging research topic. The review included 36 different predator species from 34 countries across all continents.

The most prominently featured predators were grey wolves, dingoes, coyotes, red foxes, golden jackals and domestic dogs. Over 50% of the studies came from four countries: the United States (N = 29), Australia (N = 24), India (N = 13) and Israel (N = 9).

Geographic distribution and number of studies included in the review

In the presence of the resource subsidies we found that (i) predator abundance generally increased, (ii) the dietary preferences of predators altered to include the food subsidy, (iii) life history parameters such as survival, reproduction and sociality shifted to the benefit or detriment of the predator, and (iv) predators changed their home ranges, activity and movements. In some instances, these modifications negatively affected other species via increased predation or competition.

A few of the papers we reviewed are worthy of highlighting.

One study compared coyote density across a gradient of anthropogenic food availability and found an eight-fold increase in coyote density in the most human-developed area.

Another study found that black bears exploit highly predictable waste foods by forming social aggregations and tolerating other bears around rubbish dumps.

In South-America free-roaming domestic dogs, subsidised by humans, were shown to be efficient at chasing and harassing a threatened deer species.

An influx of free-roaming dogs in Israel was found to be a major factor causing decreased recruitment of mountain gazelles.

We also found evidence for subsidy-driven prey switching behaviours. Most notable was the study demonstrating that spotted hyenas increase predation on donkeys when the availability of urban and rural waste declines during Christian fasting periods.

Surprisingly, despite the many studies demonstrating that the largest predators included in our review frequently eat livestock, this food source comprised only 17% of their diet on average. However, this may reflect the high risks associated with taking livestock such as persecution by humans, with many studies in our review indicating that even when predators use livestock, they alter their behaviour to avoid humans.

Taken together, the changes to food web interactions that we documented in our review highlight that many countries, even those technologically advanced, are addressing inadequately the problems associated with predator access to resource subsidies.

Additionally, it is clear that predators frequently utilise human-provided foods, and that the ecological effects appear to be mostly negative.

Conceptual framework depicting the potential changes to food-webs when predators access human-provided resource subsidies. Solid lines are direct effects and dotted lines are indirect effects. Subsidies result in changes to space-use, life history parameters, diet and density of predators. These responses may indirectly affect co-occurring predators and prey.

The potential changes to food web interactions when predators access human-provided foods. Solid lines are direct effects and dotted lines are indirect effects. Subsidies result in changes to space-use, life history parameters, diet and density of predators. These responses may indirectly affect co-occurring predators and prey.

In a world where human activities are continually expanding, it is crucial that humans change the way in which their waste and resources are managed in order to minimise the access of predators to these rich resource subsidies.

A key step to achieving this goal is to reduce the amount of edible food that is lost or wasted by humans.

A co-benefit of this strategy is that it may help to solve global food security problems, with roughly 1 in 8 people lacking access to sufficient food. It may also slow down the rate at which land is being converted to agriculture, which is arguably one of the biggest threats to biodiversity across the globe.

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.

 

FoxRig

 

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: http://furbearerdefenders.com/blog/episode-138-the-wolf-effect

 

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

Wolf

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

 

 

 

 

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