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View from the Lectern: Exotics Versus Natives and how to save the Chesapeake Bay

“Aliens are a problem!” was the claim from the back row.  “They don’t belong here.”  “They aren’t natural.”  “Get rid of them.” “Send them home!”

I am moderating a class debate about whether the Asian Oyster could save the Chesapeake Bay.  Once the world’s most productive estuary, the Bay’s health is failing, despite receiving lots of money and attention over the last few decades.  Even an ambitious and well-designed new initiative from President Obama might not be enough.

Once so abundant that their reefs presented navigation hazards, the native oyster could filter the Bay every 2 days or so.  Now filtering takes months if not years, and everything else suffers—crabs, fish, grasses; especially since we still dump silt, sewage, fertilizers, and pesticides into the watershed.  Commercial and recreational harvesting of oysters also continues, and there is concern that the population is not sustainable.  So serious discussion are underway about what to do.  The Asian Oyster is larger, faster growing, and resistant to diseases that weaken the native oyster, so one proposal is to insert thousands upon thousands of caged, sterilized Asian oysters into the Bay, creating oyster farms that filter the Bay and grow fresh fare for restaurants.

The class debate has two purposes: 1) to make students aware that meat-heavy diets and sprawling suburban commuting lifestyles are the real pathogens causing the Bay’s illness and 2) to confront the overly simplistic claim that natives are good and exotics are bad.  This blog examines the latter.

By some estimates, we spend millions of dollars to battle exotic species—invasive species like Kudzu, Zebra Muscles, and Gypsy Moth—and lose billions (yes that is a “b”) more through damage caused to land, crops, forests, and water intakes.  But let’s not forget the benefits.  Where would we be without economies built around cotton, wheat, beef, and honeybees?

“We must protect biodiversity,” is another quickly voiced opinion in these debates, usually from the front row.  “Really? Which biodiversity,” I ask?  Yes, our poor stewardship of the biosphere is causing the 6th great extinction of species, a holocaust our descendants will not forgive.  But species biodiversity is actually increasing in some places, such as urban areas where residents import and nurture species from around the world, often for ornamental purposes.  Perhaps those urban islands of increased diversity are more resilient, more beautiful, and otherwise better than what was there before?  Does that make exotics good, or at least OK? Or is the answer more complicated and require a careful and contextual comparison of costs and benefits?

“How about genetic diversity,” I ask?  Maybe we should worry about the spread of mono-cultures and the loss of diversity within species more than we should worry about whether something is native or exotic?  If new pathogens or climate conditions emerge to which the remaining varieties are vulnerable, then huge swaths of our biosphere might disappear, irreversibly changing conditions to something less supportive of human economy and civilization.

The most persuasive pro-native arguments follow from the precautionary principle—let’s keep what works in the biosphere until we know for sure that the replacements will work, and continue to work for a really long time.  The least persuasive pro-native arguments have some uncomfortable parallels to xenophobia and/or invoke a nature-knows-best naturalism bias.

We have entered the anthropocene, so the sorts of choices hinted at by this class debate are increasingly upon us.  Society needs a strategy to make good decisions.  Being good stewards of the Chesapeake Bay, or any ecosystem, is too complex a problem for simple answers.  Plenty of meaningful arguments exist for and against introducing a new species—whether the species is exotic, foreign, alien, or Asian is not one of them.

R. Bruce Hull, IV, Ph.D. is a professor in the College of Natural Resources at Virginia Tech practicing social ecology. His work focuses on healing forests fractured by pressures of urbanization and globalization. He is author and editor of over 100 publications, including two books: Infinite Nature (Chicago 2006) and Restoring Nature (Island 2000). He serves on the editorial advisory board for Gale’s GREENR environmental and sustainability studies web portal.

Posted on: October 20, 2011, 9:36 am Category: View from the Lectern Tagged with: ,

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