The New Kid on the Block Has Nasty Habits: Invasive Species
Posted by Richard Conniff on June 20, 2016
by Richard Conniff/Takepart.com
If it had gone undetected, a study by the U.S. Forest Service later estimated, the beetle could have killed a third of the trees in cities nationwide, at a loss of up to $669 billion. Instead, the discovery launched a major campaign to locate and contain the invasion at a handful of sites around the United States.
Here is the scary thing:
Invasions like that happen all the time. Roughly 50,000 alien species are established in the U.S., and a 2005 study put the economic and environmental costs at $120 billion a year. Most of that is in damage to agricultural crops and forests. But take a look at the plants and animals on the threatened and endangered species lists, for instance, and invasive species are the main reason about 42 percent of them are in trouble.
Scarier still, globalization of trade and increasing international travel make the danger worse each year. A new study in the journal Proceedings of the National Academy of Sciences has added up the factors determining whether a species invades another country and becomes established well enough to do serious damage. It found that China and the United States are the countries at greatest risk, in purely economic terms. That’s mainly because those two countries lead the world in international trade. For the same reason, they are also the leading sources of species likely to become invasive elsewhere.
But this all sounds a little abstract. So let’s look at a recent case study. Sometime in the 1980s, a trivial-seeming species called the spiny water flea invaded the Great Lakes and spread from there. Lake Mendota in Madison, Wisconsin, in particular, seems to have been spiny water flea heaven. Since spiny water fleas are enthusiastic predators, they demolished the population of a native species called Daphnia pulicaria. The Daphnia in turn are enthusiastic grazers, and when they disappeared, the algae boomed, turning formerly clear water murky. This is what scientists call a trophic cascade. Nonscientists just say, “What the hell happened to my lake?”
The good news, Madison, is that you can get your lake back. But since you’re now stuck with the spiny water fleas, the only practical way to do it is to get rid of the pollution that’s feeding all that algae. To be precise, it’s going to require a 71 percent reduction in the amount of phosphorous entering the lake from farms, lawns, and household plumbing, at a cost somewhere between $87 million to $163 million. (After that we can talk about Lake Monona just next door.) Multiply the mess in Madison by 10,000 or 100,000 other lakes, plus countless rivers, fields, and forests, and you may begin to see why it’s a big deal when alien species slip into the country.
What can we do to minimize the risk? The first step is to stop being stupid: We live in a time of mindless demagoguery about the dangers of “big government,” combined with an irrational drive to cut all federal funding across the board (except for the military), regardless of the demonstrable benefits. So who is going to do proper inspections at ports and airports, if not U.S. Customs and Border Protection? Who will make difficult taxonomic identifications fast enough to block invasive species at the border, other than the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service? This is one of the many reasons we have a federal government.
So call it “defense funding,” if you must. Or call it “standing up to China” when federal agents turn a ship around and order it back to its point of origin because it’s infested with Asian gypsy moths. Just accept that our taxes sometimes work to our joint benefit, and get on the phone to tell your representatives in Congress to fund these watchdogs at our borders.
One last point about the new study in PNAS: The authors don’t make a big deal of it, but there’s a poignant dark side to the international trade–invasive species equation: When you look at the potential damage to quality of life—and not just at dollars and cents—the countries that benefit least from international trade seem nonetheless to suffer the worst risks. Countries in sub-Saharan Africa in particular tend to lack diverse economies and depend largely on agriculture, leaving them highly vulnerable to invasion by agricultural pests and pathogens. For us, the risk is about economic loss. For them, it’s about not being able to feed their families. It’s a lot like what’s happening with the consequences of climate change: those least to blame nonetheless face the biggest potential hit.
That’s a hidden cost researchers and political analysts should be taking into account when they talk about the value of international trade.