Search This Blog

Monday, August 17, 2009

Alien Invasion? An Ecologist Doubts the Impact of Exotic Species

"Mark Davis is a plant ecologist at Macalester College in St. Paul who has spent the past 15 years challenging the most cherished principle of restoration ecology: that nonnative species should be eradicated from the landscape."

"Earlier this spring, he published a bombshell of a book with Oxford University Press called Invasion Biology. Davis claims that alien species have been demonized and resources wasted on purported "invasives" could be better spent protecting habitat. More than that, he disputes the maxim that invasive species are the second-leading cause of species endangerment after habitat destruction, impacting some 42 percent of threatened and endangered species. Such concerns are particularly timely as ecologists debate the risks of relocating species to save them from climate change. In June, one reviewer wrote that Davis "dares to touch the third rail of invasion biology," slaughtering some of its "sacred cows."

"In his book Davis picks apart the claim that invasive species are the second-leading cause of extinctions. He traces that meme back to a 1998 paper by Princeton ecologist David Wilcove and colleagues in the journal Bioscience, which he derides for being based on the "opinions" of field researchers. Moreover, most species said to be imperiled by invaders were located in Hawaii and on other islands, not the mainland U.S., where he is skeptical that alien species can gain a foothold. "There have been thousands of nonnative species introduced in the United States," he says, "and they have not caused one native species to go extinct."



Even the cane toad—that monster of invasion ecology depicted in the madcap 1988 documentary, Cane Toads: An Unnatural History—may not be as bad for Australia as some have claimed. Imported from South America in the 1930s, Bufo marinus soon spread from its gateway in Queensland, and researchers have since documented a much-ballyhooed trail of devastation in its wake. When molested, the amphibian secretes a milky blend of neurotoxins from glands on the back of their heads powerful enough to kill any crocodile or quoll (a catlike marsupial) that tries to eat it. Volunteers now conduct military-style operations to hinder the toad's progress, and government scientists have spent millions of dollars to build a virus to exterminate it.



"But the most respected voice in Australian herpetology, Richard Shine of the University of Sydney, says cane toad hysteria is overblown. Not a single organism has gone extinct due to the cane toad, and many have adapted to its presence. Shine has found that some snakes, such as the red-bellied black snake, are evolving to have smaller heads, which forces them to prey on smaller, less toxic cane toads. Some species of birds and rodents have also learned how to eat the toads safely by flipping them over on their bellies to avoid the toxins before devouring their organs. Life, in other words, goes on."

To read the remainder of this article please click on this link:http://www.scientificamerican.com/article.cfm?id=alien-invasion-ecologist-doubts-exotic

Source of image of the Cane toad:http://commons.wikimedia.org/wiki/File:Cane-toad.jpg

No comments:

Visit GM Alexandra Kosteniuk's Women's Chess Blog:Please click on the image below:

Visit GM Alexandra Kosteniuk's Women's Chess Blog:Please click on the image below:
Chess needs more women and girl participants and administrators!

Thoughts worth thinking about

"Our subconscious minds have no sense of humor, play no jokes and cannot tell the difference between reality and an imagined thought or image. What we continually think about eventually will manifest in our lives."-Sidney Madwed



Laws alone can not secure freedom of expression; in order that every woman and man present their views without penalty, there must be spirit of tolerance in the entire population.- Albert Einstein Too often we underestimate the power of a touch, a smile, a kind word, a listening ear, an honest compliment, or the smallest act of caring, all of which have the potential to turn a life around. - Leo Buscaglia



A person's true wealth is the good he or she does in the world. - Mohammed



Our task must be to free ourselves... by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty. -Albert Einstein



The best way to find yourself, is to lose yourself in the service of others. - Ghandi



The unselfish effort to bring cheer to others will be the beginning of a happier life for ourselves. - Helen Keller



Aim for success, not perfection. Never give up your right to be wrong, because then you will lose the ability to learn new things and move forward with your life. Remember that fear always lurks behind perfectionism. Confronting your fears and allowing yourself the right to be human can, paradoxically, make yourself a happier and more productive person. - Dr. David M. Burns



Life is as dear to a mute creature as it is to man. Just as one wants happiness and fears pain, just as one wants to live and not die, so do other creatures. -His Holiness The Dalai Lama



Mankind's true moral test, its fundamental test (which lies deeply buried from view), consists of its attitude towards those who are at its mercy: animals. And in this respect mankind has suffered a fundamental debacle, a debacle so fundamental that all others stem from it. -



Milan Kundera, The Unbearable Lightness of Being



The worst sin towards our fellow creatures is not to hate them, but to be indifferent to them. That's the essence of inhumanity. -George Bernard Shaw

Ego's trick is to make us lose sight of our interdependence. That kind of ego-thought gives us a perfect justification to look out only for ourselves. But that is far from the truth. In reality we all depend on each other and we have to help each other. The husband has to help his wife, the wife has to help the husband, the mother has to help her children, and the children are supposed to help the parents too, whether they want to or not.-Gehlek Rinpoche Source: "The Best Buddhist Writing 2005 pg. 165

The hostile attitude of conquering nature ignores the basic interdependence of all things and events---that the world beyond the skin is actually an extension of our own bodies---and will end in destroying the very environment from which we emerge and upon which our whole life depends.