Monday, October 19, 2009

Study: Cougars essential to balanced system

OSU professors to share findings in first lecture of annual series
October 19, 2009
By Stefanie Knowlton - Statesman Journal - October 19, 2009

Picture two valleys in Utah's Zion National Park.

One teems with large cottonwood trees, wildflowers, butterflies and so many frogs you need to watch your step along the stream. The other offers fewer cottonwood trees, wildflowers and only a handful of varieties of frogs, butterflies and lizards.

If you ask renowned OSU professor Bill Ripple, the more abundant landscape can be traced back to cougars.

Ripple and OSU Professor Robert Beschta, known for their work on predator, prey and plant relationships, found that cougars play an essential role in maintaining biodiversity. Ripple's latest study with colleagues outlines how smaller predators fill in the gaps left by dwindling larger predator populations and cause bigger financial and environmental headaches.

Ripple will discuss his cougar studies Oct. 22 during the first lecture in the Environmental Learning Center's annual series.

It's a timely topic, said Lisa Olivares with the Friends of Straub Environmental Learning Center.

"We've heard a lot about top predators and the public's fear about having them in our environment," she said.

But this lecture looks at the environmental consequences of removing them, she said.

There have been at least three cougar sightings in the Salem area this summer. And the Oregon Department of Fish & Wildlife recently expanded the cougar-hunting season to year-round starting in January in an effort to meet quotas.

Ripple declined to comment on Oregon's management of cougars and how it might effect the landscape.

His research in National Parks shows that when an ecosystem loses top predators such as wolves and cougars there are major effects on plant communities extending to the entire ecosystem.

"I think the studies speak for themselves," Ripple said.

So how do cougars affect ecosystems down to butterflies and frogs?

The study in Zion National Park shows that areas where cougars are scarce, the population of mule deer explodes. The deer, unchecked by predators, eat many of the young cottonwood trees, shrubs and wildflowers. Those plants no longer provide habitat and food for butterflies, frogs and lizards.

In addition, plants help slow erosion of the stream banks, which keeps the streams narrower, deeper and provides better habitat for fish. Without them, there's erosion, which sends sediment into the streams, effects water quality and widens of channels.

"The basic lesson here is the plants are the basic glue that holds biodiversity together," he said.

And the top predators keep watch over the entire ecosystem. or (503) 399-6735


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