Navigation Links
Loss of top animal predators has massive ecological effects
Date:7/14/2011

STONY BROOK, NY"Trophic Downgrading of Planet Earth," a review paper that will be published on July 15, 2011, in the journal Science, concludes that the decline of large predators and herbivores in all regions of the world is causing substantial changes to Earth's terrestrial, freshwater, and marine ecosystems. The paper claims that the loss of apex consumers from ecosystems "may be humankind's most pervasive influence on nature." The research was funded primarily by the Institute for Ocean Conservation Science at Stony Brook University with support from The Pew Charitable Trusts. The paper is co-authored by the Institute's executive director, Dr. Ellen K. Pikitch, and the lead author is Dr. James A. Estes, professor of ecology and evolution at the University of California at Santa Cruz.

The review, conducted by an international team of 24 scientists, illuminates the patterns and far-reaching impacts of predation and herbivory on the structure and dynamics of global ecosystems. The researchers relied on both experimental and observational evidence, which provides a strong basis for their conclusions.

"By looking at ecosystems primarily from the bottom up, scientists and resource managers have been focusing on only half of a very complex equation," said Dr. Estes. "These findings demonstrate that top consumers in the food web are enormous influencers of the structure, function, and biodiversity of most natural ecosystems."

Apex consumers include animals such as big cats, wolves, bison, sharks, and great whales, and are typically large, long-lived, and not amenable to laboratory experiments. As a result, the effects of removing them from ecosystems are not easy to document. The team of scientists reviewed an accumulation of theoretical and empirical evidence on how the decline of top predators and herbivores has affected Earth's ecosystems on land, in freshwater, and in the ocean. Their findings suggest that "trophic downgrading" the ecological consequences of losing large apex consumers from nature causes extensive cascading effects in ecosystems worldwide, especially when exacerbated by factors such as land use practices, climate changes, habitat loss, and pollution.

"Our review of existing studies clearly shows that a top-down cascading effect in natural systems is both powerful and widespread," said Dr. Estes. "There is an urgent need for interdisciplinary research to forecast how a continued loss of top level consumers will further harm the planet's ecosystems."

This paper documents some of the negative effects that the widespread loss of these animals has already had on Earth's biosphere, climate, biodiversity, and vegetation:

  • The reduction of lions and leopards from areas of sub-Saharan Africa caused the baboon population to swell. This unexpectedly increased transmission of intestinal parasites from baboons to humans as the primates were forced to forage closer to human settlements.
  • As large ungulates recovered from a devastating rinderpest epidemic in the Serengeti in Africa, herbivory increased, and the frequency of wildfire declined in that region. Wildfire frequency increased following the late Pleistocene/early Holocene decline of megaherbivores in Australia and the northeastern United States.
  • Industrial whaling in the 20th century resulted in the loss of large numbers of plankton-consuming great whales, which are now known to sequester carbon into the deep sea through deposition of feces. The result has been the transfer of approximately 105 million tons of carbon into the atmosphere that would have been absorbed by whales, contributing to climate change.

"We must assume going forward that significant changes to the ecosystem are occurring when large predators and herbivores are removed from the top of the food web, and, thus, that efforts to manage and conserve nature must include these animals," said Dr. Pikitch. "An old paradigm has shifted, and those who question this theory now have the burden to prove otherwise."


'/>"/>

Contact: Cindy Yeast
cdyeast@earthlink.net
720-542-9455
Stony Brook University
Source:Eurekalert  

Related biology news :

1. Long-term study shows effect of climate change on animal diversity
2. Researchers find animal with ability to survive climate change
3. Researchers note differences between people and animals on calorie restriction
4. Earliest animal footprints ever found -- discovered in Nevada
5. Details of evolutionary transition from fish to land animals revealed
6. Drug-embedded microparticles bolster heart function in animal studies
7. Swamping bad cells with good in ALS animal models helps sustain breathing
8. Moderate use averts failure of type 2 diabetes drugs in animal model
9. Grapes may aid a bunch of heart risk factors, animal study finds
10. Animal and biological science highlights: San Antonio Fluid Dynamics Conference, Nov. 23-25
11. Discovery of giant roaming deep sea protist provides new perspective on animal evolution
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Loss of top animal predators has massive ecological effects
(Date:12/5/2016)... 5, 2016  The Office of Justice Programs, ... CT Scans Enhance or Replace Medico Legal Autopsies?" ... supporting or replacing forensic autopsies with postmortem X-ray ... In response to recommendations made by The ... CT scans as a potential component of medicolegal ...
(Date:11/30/2016)... , Nov. 30, 2016 Not many of us realize that we ... of recovery so we need to do it well. Inadequate sleep levels have been ... blood pressure, stroke, diabetes, and even cancer. Maybe now is the best ... that could help them to manage their sleep quality? ... ...
(Date:11/29/2016)... Lithuania , Nov. 29, 2016 /PRNewswire/ ... biometric identification and object recognition technologies, today ... (SDK) for fingerprint recognition solutions that run ... a fingerprint template using less than 128KB ... in compact devices that have limited on-board ...
Breaking Biology News(10 mins):
(Date:12/6/2016)... , ... December 06, 2016 ... ... the Almac Group, the world’s largest privately-held contract pharmaceutical development and manufacturing ... Health, a leading biopharma outsourcing company combining a leading CRO and the ...
(Date:12/6/2016)... ... December 06, 2016 , ... Symbios Technologies, Inc. , ... company has engaged in a collaborative research partnership with Colorado State University (CSU) ... of the Vice President for Research. This agreement is designed to further the ...
(Date:12/6/2016)... -- Zimmer Biomet Holdings, Inc. (NYSE and SIX: ... of its previously-announced cash tender offers (the "Offers") ... accrued and unpaid interest to, but not including, ... expenses related to the Offers) (the "Maximum Tender ... table below (collectively, the "Notes"). The terms and ...
(Date:12/6/2016)... ... December 06, 2016 , ... ... management solutions headquartered in Aurora, Ohio, announced the opening of their new office ... the newly constructed facility is home to 200 employees focused on providing sales, ...
Breaking Biology Technology: