In my plant systematics lecture this morning we touched (very) briefly on the subject of so-called "invasive species." I realize that my use of the qualifier "so-called" and my use of quotation marks go against the grain, at least in environmental circles, but I have a serious philosophical problem with how the issue of "invasive species" is handled.

It's not at all that I object to the goals of invasive species management, but I object to the philosophy and reasoning that underlies a lot of the arguments as to why it is important. Specifically, I can't abide those who believe that preventing the spread of species is to hold back some insidious unnatural process.

The spread of species is a natural process. Many plants depend on animals to disperse seeds and human beings are perfectly valid disperses. We're not special just because we're human. One of the prime reasons that an animal might be complicit in spreading plant seeds is that the plant provides some reward to the animal for doing so -- often some kind of food reward -- but for whatever reason, the plant is attractive to the animal. Plants make themselves attractive to us in many ways: agriculturally, pharmaceutically (both for therepeutic and recreational purposes) and aesthetically. Many of the rewards we get from plants cause us to grow them in locations where they did not previously exist, and in many circumstances they have a competitive advantage in the preexisting plant communities. Nothing here should be considered unnatural or immoral.

Certainly the degree to which human beings spread plants is one which we have no evidence of ever occurring in the past, but just because we're terribly effective dispersers does not mean that it's somehow unnatural. Plants that have become attractive to human beings -- including those plants that are attractive because of their plasticity in response to selective breeding such as Brassica oleraceae -- have a distinct reproductive advantage over plants that are not attractive to us.

As a species that tends to think of itself as enlightened and as environmentally and scientifically literate individuals who are particularly so, we need to stop taking ourselves out of the equation when we speak of natural selection and Earth's ecosystems. If we want to make it a priority to attempt to control "invasive species" (and I believe we should), we can't pretend to be doing it from way up on some moral high ground. We need to recognize that one of the main reasons it is important is because it affects us, not because we think there's a moral imperative to protect some rare wetland sedge from being overwhelmed and replaced by some other eurasian sedge. We may feel that it is a moral issue at times, but I think that feeling results from a greater awareness of exactly how interconnected and interdependent Earth's species are. Those who argue environmental issues with pretensions of moral superiority are doomed to fail; even I can't suffer them long. However, I sincerely believe that many environmental activists are not aware of how much their arguments revolve around self-interest and may in fact believe in the "high moral purpose." These people would do well to honestly examine their motivations.

Recommended Reading: The Botany of Desire by Michael Pollan
This book includes a fascinating chapter on marijuana (Cannabis sativa and Cannabis indica) including not only how human beings have been intertwined in its evolution as a result of the rewards it offers (psychoactive compounds, responsiveness to selective breeding/hybridization, ability to grow well indoors) but also the effects that criminalization has had on how the plant has developed in the past century or so. Further, he includes an astoundingly insightful commentary on the human desire for intoxication. For anyone interested in "the interconnectedness of things," this is a must read.