Lessons from Nature: invasive aliens

Invasive species alert sign
Sign warning of the presence of zebra mussels, an invasive alien species.
Migrants throwing rocks at helicopter
Central American economic migrants throw rocks at a circling helicopter in Mexico, on their way to the United States (where they plan to illegally cross the border), November 2018.

I have spent a lot of years of my life teaching outdoor and environmental education, conservation education, and sustainable agriculture education. And one thing I have learned, as a guiding principle, is that the natural world can often serve as a lens through which to view human society with greater clarity and awareness.

Let me cite one example, which seems to be impinging itself upon us, here in the West, with greater and greater urgency:

It is now a commonplace, among the “talking heads” of the Western media, political, and academic elite, that “diversity is a strength.” Some even go so far as to say that diversity is “our” strength. The notion is not completely without merit: there is a type of diversity which can be a strength.

The biologist and ecologist E.O. Wilson, for example, has demonstrated how biodiversity can greatly enhance resilience: the ability of, for example, a natural forest ecosystem to resist the impacts of a changing climate, or infestation by pests or diseases, especially as compared to a monoculture tree plantation, or a grain farm.

But – and this is a big “but”! – this is true only of a certain type of diversity, the sort which comes about naturally, over centuries or even millennia. An example in the natural world might be a healthy forest, meadow, or wetland. And example in human society might be the tremendous diversity of cultures, customs, and tradition which make up the vibrant tapestry of Europe.

Ecologists have long recognized the existence of a category of organisms to which “human ecologists” appear oblivious (or, more accurately, feel socially and politically constrained to ignore or deny): invasive aliens, which often find fertile soil in a new ecosystem, in which are there few or no natural controls to limit their spread. Invasive aliens in their original locality are perfectly fine and non-disruptive, because there are natural controls that limit their spread, and prevent them from getting out of hand.
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