With a name such as “invasive” its hard for an emerging species in a new biome to establish a good reputation.  An “invasive species” can be defined as an organism establishing a presence in a newly introduced area not native to it whether by accidental or intentional means.  For the most part, as stated by the New York Times, it has been the general opinion of conservation organizations to either eradicate or eliminate the invasive species.  However, a large number of scientists including Dov Sax and Ken Thompson, both professors of Ecology at Brown University and the University of Sheffield respectively, are beginning to dispute this idea.  Dr. Thompson claims that species have been moving around for centuries and that humans play a large role in their movement.  In a modern era of globalization, it is getting increasingly harder to stop the spread of “invasive” species and climate change is multiplying the number of species considered “invasive” drastically.  Although Thompson’s theory has a large following, it is not universal.  Some “invasive” species are undeniably harmful such as the fungus that causes chestnut blight which decimated thousands of trees across America in the 1900s or more recently the Zika virus spreading rapidly through mosquitoes drawn north by the warmer climates.  It has been discovered that islands and mountaintops are even more susceptible to these species due to their isolation and indigenous population’s lack of evolutionary defenses.  For example the the accidental transport of the brown tree snake to Guam has nearly eliminated the bird population.  However, this general trend has given many nonnative species a bad representation.  For example, monarch butterflies of California prefer to live in the eucalyptus tree which was brought there 150 years ago.  Or the nonnative crayfish pictured above which feeds the migratory wetland birds of Spain.  In fact the term “invasive species” was coined in Charles Elton’s 1958 book The Ecology of Invasions by Plants and Animals drawing from the heightened tensions caused by World War 2.  This term did not gain its modern weight until the 1990s when the field of Invasive Biology began to grow popular.  Despite findings such as the ones by Thompson and Sax, this is still a much highly debated topic in the field of biology.

original article:http://www.nytimes.com/2016/03/01/science/invasive-species.html?action=click&contentCollection=science&region=rank&module=package&version=highlights&contentPlacement=1&pgtype=sectionfront&_r=0




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