Thomas Newsome

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Unravelling the complexities of multi-predator systems in managed landscapes

In December last year I spent two weeks out on the Washington Wolf-Deer project. The biggest eye opener was the diversity of large predators in the system. On top of wolves, there are bears, cougars, coyotes and bobcats.

Clockwise from the left - a bear, cougar, bobcat and coyote caught on wildlife cameras in the study site

Clockwise from the top left: a bear, cougar, coyote and bobcat caught on wildlife cameras in the study site

For an Australian who is used to studying the interactions between three small-medium sized predators (the dingo, red fox and feral cat) the idea of having all these large predators within a study site is a new challenge.

For example, there is debate in Australia about the ecological role of dingoes. Indeed, we struggle to unravel the complex relationships between dingoes, red foxes and feral cats. So attempting to understand how wolves, bears, cougars, coyotes and bobcats interact with each other is a whole new ball game.

Because wolves have recently recolonised Washington State it is possible to study interactions between predators in two different scenarios being with and without wolves.

As mentioned in a previous post (https://thomasnewsome.com/2013/11/26/from-desert-dingoes-to-alpine-wolves/), the research group from the University of Washington are putting camera and GPS collars on two deer species to look at behavioural changes in response to recolonising wolves.

During my first two weeks on the Washington Wolf-Deer project we set out traps to catch the deer each night. Unfortunately the lack of snow made it difficult to lure deer into the traps using alfalfa, old apples and molasses (deer are much easier to catch when there is snow because the grass is covered and inaccessible to eat).

Deer trap in the study site

Deer trap in the study site

In early January I made the trip back to the field site hoping that with more snow there would be a higher chance of catching deer. Fortunately, success!

A white-tailed deer ready for release with GPS collar fitted

A white-tailed deer ready for release with GPS collar fitted

The additional impetus for heading back out in the field was the company of a fellow Australian researcher, Prof. Chris Dickman, who had a few days to spare after we attended the Gordon Research Conference on Predator-Prey interactions in California.

Poster presentation at the Gordon Research Conference on Predator-Prey Interactions. Poster title: a continental scale trophic cascade from wolves through coyotes to foxes

Poster presentation at the Gordon Research Conference on Predator-Prey Interactions. Poster title: A continental scale trophic cascade from wolves through coyotes to foxes

Chris has spent his career working in the arid deserts of Australia. Fortunately, I found enough warm clothes to see him through a North American winter field experience.

Chris Dickman (left - aka michelin man) and Tom Newsome (right) with views of the field site

Chris Dickman (left – aka michelin man) and Tom Newsome (right) with views of the study site

Working in a complex multi-predator system raises a plethora of ecological questions for consideration.

For example, with wolves in the system, is the “top-dog” canine or feline?

Cougars and wolves will both be competing for resources (deer) so there is the question of whether or not wolves will out-compete cougars. Wolves are also known to suppress coyotes so there is the question of whether or not coyote density will decline in areas where wolves are present.

Some of these questions were addressed after wolves were reintroduced into Yellowstone National Park in 1995-1996. However, in Washington State, wolves have recolonised managed lands where there are hunting seasons, logging and cattle ranching. Therefore, the future persistence of wolves in managed lands depends on minimising negative interactions between people and wildlife.

It also depends on the ecological role of wolves in managed lands i.e. how they interact with other predators and prey.

The results from the Washington Wolf-Deer project therefore have important implications for understanding how people, wolves and other wildlife might be able to coexist in managed lands.

When results from the project become available I will be sure to share them here.


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