Archive for April, 2011

Give Me Your Tired, Your Poor, Your Huddled ….. Invasive Species?

April 11, 2011

Yesterday, the Sunday New York Times printed my letter responding to a guest editorial that actually praised invasions by non-native species. My letter in the times was a shorter version of a longer piece that’s below (thanks to GLU’s Jen Nalbone for some great edits!). Also, check out the other letters that ran in response to the guest editorial.

Here’s my original piece:

For a minute, I thought Hugh Raffles’ New York Times op ed, “Mother Nature’s Melting Pot” was a bit of a satire – perhaps a modern adaptation of Swift’s “A Modest Proposal.” After all, Raffles compares the anti-immigration fervor with the attempts to stop invasive, “alien” species from colonizing native habitats in the U.S. But as I read, I got the sinking feeling that Rafferty is serious. He argues, human diversity is good; the iconic “melting pot” has made the United States what it is today. He seems to ignore that he’s talking about diversity among a single species, humans. Would he be as positive about welcoming species into the U.S. that eat humans? Or that kill us through disease? Because that’s what harmful invasive species often do to native species. Shall we open our arms, say, to SARS or the Asian flu? After all, those organisms are just yearning to be free.

What Raffles seems to forget is that our society does welcome many invasive species, like ornamental plants and shrubs, soybeans, and housecats. What we try to stop (or once they are here, control or eradicate) are the few non-native species that turn out to be invasive, or harmful to humans and the habitats we rely on.  Just as we use vaccines, screening and antibiotics to stop diseases that hurt us, so do we use similar techniques to stop the bad invasive species.

And there are bad ones – species that can hurt humans, and species that actually reduce the biological diversity in an ecosystem. Living in the Great Lakes, we see evidence of that on a daily basis. One of them is zebra mussels, which coat the bottom of the Great Lakes and many beaches with six-inch thick mats of tiny, sharp shells. Raffles says that zebra mussels have had a significant positive effect on the Great Lakes because they make filter the water, making it clearer and increasing populations of fish and plants. Problem is, that’s just flat out wrong. Due to zebra mussels and their incredible ability to filter out microscopic organisms, there’s no food left in the water column of vast sections of the Great Lakes and fish populations have crashed. A new article in Environmental Science  and Technology this month documents that fish biomass in two Great Lakes has declined by 95% in the past 15 years, primarily due to zebra mussels and their cousins, the invasive quagga mussels. And according to scientists, because zebra and quagga mussels spit out toxic algae as they consume virtually all the rest, they are the primary culprits in causing harmful algae blooms in the Great Lakes – thick pea-green soup that can poison drinking water and lead to botulism outbreaks.

And that’s only one harmful invasive species. How about viral hemmorhagic septicemia (VHS), the Ebola of fish that causes them to bleed out and die? Shall we roll out the welcome mat for that one?

Biology doesn’t say one species is bad and another is good (although I would argue that an invasive species that wipes out all or many of the other species in an ecosystem is biologically bad). But people value some things above others… including our own survival and prosperity. Call me people-ist, but I prefer native species that don’t hurt me or kill me. So no more harmful invasive species, please!