2016-02-29. Invasive Species Aren’t Always Unwanted.

posted Mar 1, 2016, 8:33 PM by Alan Gould
By Erica Goode, The New York Times. For GSS Ecosystem Change chapter 6. Excerpt: Invasive species are bad news, or so goes the conventional wisdom, encouraged by persistent warnings from biologists about the dangers of foreign animals and plants moving into new territories. Conservation organizations bill alien species as the foremost threat to native wildlife. Cities rip out exotic trees and shrubs in favor of indigenous varieties. And governments spend millions on efforts to head off or eradicate biological invaders. ...But a growing number of scientists are challenging this view, arguing that not all invasive species are destructive; some, they contend, are even beneficial. The assumption that what hails from elsewhere is inherently bad, these researchers say, rests more on xenophobia than on science. ...Many common animals, plants and insects are not native to the environments in which they are now found. Take this quiz and learn more about the living things that surround you. ...“We’re actually moving plants and animals around the world all the time,” he said. “We have been for centuries.” ...Eradicating most invasive species is virtually impossible in an era of globalization, they note. And as climate change pushes more species out of their home ranges and into new areas, the number of so-called invaders is likely to multiply exponentially. ...Some alien species are undeniably harmful, a fact that neither Dr. Davis nor others who share his view dispute. The fungus that causes chestnut blight, for example, decimated thousands of trees and changed the American landscape in the early 1900s. The Zika virus is invading new regions, carried by infected mosquitoes that some say are being driven northward by warmer temperatures. ...In a paper published last month in the journal Conservation Biology, two scientists in California, Michael P. Marchetti and Tag Engstrom, describe the “paradox” of species that are under threat in their native range but are viewed as invasive in other places they have settled....  http://www.nytimes.com/2016/03/01/science/invasive-species.html