Who Are the Real Invasives?

Zebra Mussels?  Kudzu?  Mute Swans?  Or Us?

The definition of what an “invasive species” is depends on context and point-of-view.  From the species’ point of view, of course, circumstances, competition and survival are vital factors.  Therefore, whatever kettle of soup, so to speak, you find yourself in, you need to figure out what’s available to keep you going and to stave off anything else looking for the same thing you need. 

Let’s say I’m a zebra mussel and, through completely accidental good fortune, my fellow Dreissena polymorpha and I land on the foreign shore of a large fresh water lake where we set up shop.  We are filter feeders, which means, after we open our shells, we siphon in water, extract algae (mostly), then filter the water out.  We are celebrated around inland lakes as natural water cleansing agents, which allow deeper penetration of sunlight, which permits water fauna growth at greater depths.  In other words, within reason, we help a system’s eco-system.  If there are too many of us, though, we tend to be pigs (nothing against pigs) about the algae filtering and take too much, depriving other algae-dependent species, like, well, most fish from securing what they need for survival.

Partly because of this, Canadian and American humans in the Great Lakes’ area are out to get us.  For one thing, our females can lay over one million eggs in a season, so with no known natural predators, we can eventually take over an entire maritime eco-system, literally smothering other lake life by the sheer magnitude of our numbers—and we do have a habit of doing this.  We also love getting into pipes, water treatment plants and other facilities where, again, because there are so many of us, we clog everything up and cost taxpayers and consumers in the U.S. and Canada billions of dollars every year. 

So, humans call us “invasive” because, although we are originally from Eastern Europe and managed to immigrate to Western Europe around 300 years ago, in the 1980s we immigrated to North America via ocean liner ballast water, and arrived not far from the Motor City (and some other places). It didn’t take us long, barely two decades, to clog the Great Lakes.  We aren’t liked where we are right now . . . much like kudzu.

Ah, kudzu!  Although I’ve never heard of Walt Whitman: I hail myself!  How could naive Euro-Americans have known what they were letting into their Reconstruction South when they put me on display as an ornamental bush at the New Orleans Exposition in 1883? They call me “The vine that ate the South” (1).  We should change "ate" to "eats" because I’m still chomping away, so to speak: we kudzu plants grow out of control, and in the process, suffocate any and all plant growth unfortunate to be under us.  Needless to say, this rampant habit of ours does not benefit biodiversity in eco-systems.

The funny thing is, in northern China, Japan and Korea, where we are from originally, we thrived well and did not pose any galloping threats.  Why?  Because the climate is temperate, so we lost our leaves and basically died above ground over the winter; but, when we traveled at the hands of humans, we found ourselves in places where we just kept growing and growing and growing--I honestly think that Energizer Bunny got the idea from us.  But back to my point: although we are still admired for our ability to provide comforting shade on southern porches, increasingly we are viewed as hated Mongol hordes, invaders, killers. 

We do have our uses, however, as livestock feed, in medicines, as basketry fibres, even for paper and clothing, et al.  But, like zebra mussels, our harm outweighs our good.  As invasives, we are out of context, kind of like plopping a big handful of parsley on a birthday cake: ruins the whole mood.

Here’s another mood ruiner: let’s say I’m a beautiful, elegant mute swan.  Here’s a picture of me and my mate—we connect for life, you know!

Our Cygnus olor ancestors came to this country to be used as decoration on large estates for folks like the Rockefellers, the Roosevelts, the Carnegies, you know, the 1%ers of their time.  Some of us also landed in zoos; well, we didn’t literally “land” there because we were shackled and caged there by our human captors.

About 100 years ago, some of us escaped captivity and established successful wild populations in New Jersey, New York and Long Island.  Wildlife folks estimate that there are about 5,000 of us now, spread throughout the Northeast.  No one argues against our beauty and majesty, but we are a non-migratory waterfowl, so when we identify a wetland as ours, we stay put; and because we are very large birds and aggressively territorial, we drive away and sometimes kill native waterfowl.  Plus, we have a wing span of 7’ and with a 4’ underwater reach, and due to our long necks, we can reach down quite far into ponds and lakes to consume the 4-8 pounds of vegetation we need each day to survive.

Our aggressive territorial habits and consumption needs have gotten us into trouble.

“Over the winter [NY State’s Dept. of Environmental Conservation] DEC became the target of public outrage after it issued a draft plan that entailed eradicating the state’s entire population of 2,200 mute swans by 2050, claiming that they’re an invasive species who pose a threat to native wildlife and are aggressive toward people” (2).

Um.  Excuse me?  We’ve been here 100+ years—longer than, well, you could name any number of immigrant groups, like Italians, Vietnamese, Lebanese, Jews, Mexicans, blah, blah, blah.  Get it?  We came to the U.S. by force, adapted, found a niche for ourselves and our families, but now we are regarded as “invasives,” so it is necessary to put us into the sites of guns, which two NY State DEC officers did two weeks ago, killing the two parents pictured below, even though the state had put a moratorium on killing us due to opposition from human groups who recognize our right to life and the significance of our iconic beauty:

Anyway, those four cygnets (baby swans) were left without parents.  Well, they are invasives anyway—much like the children of Mexican immigrants who do not yet have legal status.

Given the human tendency to determine what is a ‘fact,’ based on what serves or fits human purposes, perspectives, the prevailing value system, sure! mute swans are invasives because the point of view and context reality changed.  

Consider horses.  There were NONE! on either the South or North American continents before the Spaniards brought them.  Weren't horses an invasive species?  Yes, they were, but humans liked them . . . a lot. Horses fit smoothly into North America's Great Plains eco-system, and humans found them useful.

But what about humans themselves?  They are the ultimate invasive species, marching or blundering into wherever they do and not, generally speaking, considering the impact on what is already there.  Humans are ‘the better species’ or the ‘higher species,’ so their behavior, their decisions rule.  If an eco-system is harmed?  Oh, well. And tough luck to those for whom they develop distain.  Die invasives, die. (In some cases, this attitude is being demonstrated right now at the U.S.-Mexican border . . . a different kind of eco-system, but an eco-system nonetheless.)

Certainly, zebra mussels and kudzu need to be brought under control.  The lesson we can learn from their introduction into a new context is to be investigative and cautious before we introduce new species in new places.  As far as the species themselves, such as mute swans, are concerned, it would be most ethical to find a way to let them stay, and to monitor the populations of migratory waterfowl to determine if their numbers are negatively impacted by mute swan competition and aggression.  If so, let informed wildlife officials do what is necessary . . . short of total extermination.

I focused here on just three “invasive species,” but there are hundreds and hundreds of examples from all over the world available to use, and many sometimes ridiculous stories to tell—like the 3,000 mile rabbit fence in Australia, or the decimation-by-goat of the Galapagos Islands, or the massive extinction of birds in Hawaii—known as “the extinction capital of the world” (3)—thanks to Captain Cook and a whole lot of rats and cats--talk about invasives!

My point, however, is that humans are the real invasive species.  We’ve been invading new lands since we first began our trek out of Africa.  The problem with us in the last 500 years or so is twofold:  1) Our population has grown exponentially.  It’s out of control, and from an International Space Station perspective, we are the ones clogging the waterways and smothering everything under us.  2) Our rampant technologies are facilitating a global eco-system increasingly out of balance, for which other species are paying with their lives, and for which we, too, are starting to pay with decreased diversity and quality of life in virtually every eco-system on Earth.

1. http://en.wikipedia.org/wiki/Kudzu_in_the_United_States

2. http://www.care2.com/causes/mute-swan-parents-killed-in-new-york-despite-promise-of-protection.html

3. http://planetearth.nerc.ac.uk/features/story.aspx?id=129&cookieConsent=A