Sunday, July 31, 2005

Are all non- native species bad?

Ron Bailey doesn't think they necessarily are. He also deplores the fact that you aren't supposed to talk about it.

" "That kind of information is dangerous," scolded Jodi Cassell. Cassell, who works with the California Sea Grant Extension program, was speaking at a symposium on "Alien Species in Coastal Waters: What Are the Real Ecological and Social Costs?" at the February American Association for the Advancement of Science meeting in Washington, D.C. She wasn't alone in her alarm. "We have members of the press here," warned a member of the audience. "I am very concerned that they might think that his view is the dominant view."

"The target of this shushing was Mark Sagoff, a philosopher from the University of Maryland who has worked with Maryland's Sea Grant program to determine how the Chesapeake Bay's unique ecology defines a sense of place. Sagoff's sin? He'd had the temerity to point out the benefits that the much-loathed zebra mussels had brought to the Great Lakes.

" "There has been a striking difference in water clarity improving dramatically in Lake Erie, sometimes six to four times what it was before the arrival of the zebra mussels," according to the U.S. Geological Survey's Nonindigenous Aquatic Species Database. "With this increase in water clarity, more light is able to penetrate deeper allowing for an increase in macrophytes (aquatic plants). Some of these macrophyte beds have not been seen for many decades due to changing conditions of the lake mostly due to pollution. The macrophyte beds that have returned are providing cover and acting as nurseries for some species of fish." What's more, zebra mussels provide food and habitat for all sorts of native fish and ducks".

Bailey is provocative, though he hardly has the last word. For a more detailed examination of the state of the art, check out Out of Eden by Alan Burdick, a good and even- handed book about the ecology of biological invasions. (On the cover is an unquestionably bad invader, the brown tree snake that wiped out Guam's birds).

3 comments:

Steve Sailer said...

I enjoy seeing green parrots fly overhead in Los Angeles. Evidently, they are escaped pets.

There are large parakeets who live in the trees near the Museum of Science and Industry in Hyde Park in Chicago. I have no idea how they survive the winters.

Steve Bodio said...

Steve-- these are probably monk parakeets, communal tree nesters from southern South America, who have no problem with cold. I believe there are also colonies in Long Island.

Matt Mullenix said...

We have Monks overhead in New Orleans also, a very well-established population that makes its home in the old quarters of the city, building huge communal nests in the palm trees. They are fantastic athletes and look like neon-green mourning doves as they zip past.

For a REAL exotic avifauna, try Miami Florida. If Hurricane Andrew's forible release of hundreds of birds fromthe Miami Zoo wasn't enough, Miami has been a hub of wildlife trade (both kinds) for many decades. Forget parrots --- look out for Macaws, Maribu Storks, Great Black Hawks and Hornbills!