HOME >> BIOLOGY >> NEWS
Wolves' top-down effect

Willow trees, riparian willow warblers and beaver dams once were bountiful in an area near the town of Banff, Alberta, Canada. But once wolves left this area, elk grew more plentiful, browsing heavily on young willows. Today, there is little trace of beavers, and sparrows have replaced the warblers in what is now a grassland meadow. These profound changes were driven by the absence of the wolf, a top predator. That's the compelling finding of the paper, "Human Activity mediates a Trophic Cascade caused by Wolves" that appears in the August issue of Ecology by Mark Hebblewhite (University of Alberta) and colleagues.

Top-down effects of predators are called trophic cascades. While studies have demonstrated this phenomenon in aquatic environments, the Hebblewhite et al study is one of the first terrestrial, large-scale studies that so clearly exemplifies the strong role played by a top predator.

In the mid-1980s, wolves naturally recolonized the Bow Valley of Banff National Park in Alberta, Canada. The nearby town of Banff has been steadily growing and prevented wolves from fully recovering in areas surrounding the town while wolves fully repopulated adjacent areas. Hebblewhite and his fellow researchers were able to examine the effects of wolf exclusion on elk--wolves' preferred prey--on plants such as willow, which are favored by the ungulates, and on other species that depend on the willow habitat.

Hebblewhite and his colleagues found that in the low-wolf area of Bow Valley elk populations were 10 times as high as in the high-wolf area.

"We also found that as elk populations climbed, active beaver lodges declined, probably because beavers could no longer find sufficient trees with which to build their dams," says Hebblewhite.

In addition, songbirds, such as the American Redstart, which is strongly dependent on willow, also vanished from the wolf-excluded area.

Although the presence of people in the Bow Valley
'"/>

Contact: Annie Drinkard
annie@esa.org
Ecological Society of America
1-Aug-2005


Page: 1 2

Related biology news :

1. Smokeless tobacco more effective than cigarettes for delivering dangerous carcinogens into the body
2. Grapes, soy and kudzu blunt some menopausal side effects
3. Developing a more effective vaccine for tuberculosis
4. Cost-effective method for gene silencing is featured in Cold Spring Harbor Protocols
5. Negative effects of plastics additive blocked by nutrient supplements
6. Implanon, Norplant and Jadelle are all effective contraceptives -- but side effects vary
7. High blood pressure medication strategy proves effective in Hispanic women
8. Study shows cane sugar, corn sweeteners have similar effects on appetite
9. New compound effectively treats fungal infections
10. Northern forests less effective than tropical forests in reducing global warming
11. Cisplatin is more effective than carboplatin for treating nonsmall cell lung cancer

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:8/5/2020)... ... , ... Regenative Labs has received approval from the Centers for Medicare & ... first Wharton’s jelly allografts to be assigned a Q code and be approved for ... Wharton’s jelly allograft product to be recognized as a 361 HCT/P by CMS regulated ...
(Date:7/18/2020)... ... July 16, 2020 , ... A study has been published ... Neoasis™ active noise control device to attenuate typical noises in a simulated neonatal ... the alarm sounds from patient monitors, ventilators and other bedside devices that would ...
(Date:7/2/2020)... ... July 01, 2020 , ... AltruBio Inc. http://www.altrubio.com ... a biologic for the treatment of steroid-refractory acute graft-versus-host disease (SR-aGVHD), at European ... J Martin of the Fred Hutchinson Cancer Research Center, this single-arm, open-label Phase ...
Breaking Biology News(10 mins):
(Date:8/12/2020)... FARMS, Mich. (PRWEB) , ... August 12, 2020 ... ... Consulting Group, Inc. (EMMA International), a global leader in FDA compliance consulting ... of the nation’s fastest-growing private companies. The list represents a unique look at ...
(Date:8/3/2020)... (PRWEB) , ... August 03, 2020 , ... ... collection, today announced Jim Corrigan, President and CEO has been named one of ... broad cross-section of industry sectors, PharmaVoice 100 honorees are selected based on how ...
(Date:7/31/2020)... ... July 29, 2020 , ... R3 Stem Cell International is ... $3950. With 50 million stem cells total, patients may choose which extremities they would ... for arthritic joints (BMC Musculoskelet Disord. 2016). At R3 International, umbilical cord tissue is ...
(Date:7/31/2020)... ... July 29, 2020 , ... ... transmitter systems that can be configured to drive Klystrons, TWTs, IOTs, and magnetrons. ... drive one or two switches in a push-pull configuration; yielding fast fall time ...
Breaking Biology Technology:
Cached News: