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Loss of Top Predators is “Humankind’s Most Pervasive Influence on Nature”

Loss of Top Predators is “Humankind’s Most Pervasive Influence on Nature”


According to a review paper titled Trophic Downgrading of Planet Earth, published last week in the journal Science, killing top predators is humankind’s most pervasive influence on nature that has far reaching and devastating effects.

The study was conducted by a team of 24 scientists from around the world who compiled evidence from both experiments and observations to draw conclusions about the decline of top predators and herbivores on land, in the ocean and in freshwater.

“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,” according to a statement from the Institute for Ocean Conservation Science, which provided major funding for the study, along with Pew Charitable Trust.

Some of the additional consequences noted were changes in vegetation, water quality, the frequency of wildfires, invasive species and the spread of infectious diseases. The review cited examples from the vegetation recovery after wolves were reintroduced at Yellowstone to the increase in intestinal parasites spread from baboons to each other and humans as a result of the loss of lions and leopards in Africa.

“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 lead author Dr. James A. Estes, professor of ecology and evolution at the University of California at Santa Cruz. “These findings demonstrate that top consumers in the food web are enormous influencers of the structure, function, and biodiversity of most natural ecosystems.”

The report also notes that we are experience the sixth mass extinction in history, but it’s the first to be caused by humans and despite the number of studies that can be conducted while animals are still alive, no one actually knows what the effect will be until they disappear.

“It’s not reporting on any new findings, but I would say its value is that it is a synthesis,” said Matthew Kauffman, a professor at the University of Wyoming, who is not part of the study. “It’s showing us that there are top-down effects of large predators and large herbivores among many different ecosystems, functioning in many different ways. It allows us to see the full scope of the value of having top predators in ecosystems.”

“To the extent that conservation aims toward restoring functional ecosystems, the reestablishment of large animals and their ecological effects is fundamental,” Estes said. “This has huge implications for the scale at which conservation can be done. You can’t restore large apex consumers on an acre of land. These animals roam over large areas, so it’s going to require large-scale approaches.”

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Photo credit: Cryptowolf via flickr

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7:38PM PST on Jan 9, 2013


11:39AM PST on Jan 9, 2013

iT IS A SAD COMMENTARY THAT THE HUMANS THAT ARE THE DEPARTMENT OF AGRICULATURE which we elected (well some of us voted or not for them) decide when and how animals in the wild are caught, domesticated and killed for food or human hunting, Please sign petitions against this practice and write or email the Department of Agriculture, Fishing etc to stop killing or eliminating wolves, cougars, wildlife, etc. including horses for animal control population.

8:58AM PST on Dec 11, 2012

Thank you for sharing.

3:22PM PDT on Sep 4, 2012

Thank you for article.

3:21PM PDT on Sep 4, 2012

Thank you for article.

10:18AM PDT on Aug 20, 2012

Grazie per la condivisione.

4:52AM PDT on Aug 10, 2012

“Aren’t humans amazing? They kill wildlife – birds, deer, all kinds of cats, coyotes, beavers, groundhogs, mice and foxes by the million in order to protect their domestic animals and their feed. Then they kill domestic animals by the billion and eat them. This in turn kills people by the million, because eating all those animals leads to degenerative – and fatal – health conditions like heart disease, stroke, kidney disease, and cancer. So then humans spend billions of dollars torturing and killing millions more animals to look for cures for these diseases. Elsewhere, millions of other human beings are being killed by hunger and malnutrition because food they could eat is being used to fatten domestic animals. Meanwhile, few people recognize the absurdity of humans, who kill so easily and violently, and once a year send out cards praying for “Peace on Earth.”~Revised Preface to Old MacDonald’s Factory Farm by C. David Coates

3:02PM PDT on Jul 24, 2012

Good article! I agree! - we need our natural predators in wildlife...they are vital!
Because of man, ecosystems on the planet are imbalanced - we're the ones who should immediately change our bad habits!
We're the ultimate predator on this planet, and lo mismo, our ravaging ways and overpopulation are the biggest problem to deal with!

3:05PM PDT on Jul 7, 2012

AGAIN WHAT IS WRONG WITH US. That we have to kill animals because we don't like them etc.
God did not put them on this earth so we can turn around an kill them all.
What next PEOPLE

6:33PM PDT on Mar 29, 2012

"If you have men who will exclude any of God's creatures from the shelter of compassion and pity, you will have men who will deal likewise with their fellow men. ---St. Francis of Assisi..."

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Hunters are very vile dusgusting creatures that deserve to die and go back to hell where they belong.…

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