Invasives: Upsetting Nature’s Order

This piece ran as a newspaper op/ed in early August, 2023

****************************************

The destructive impact of invasive species demonstrates the fundamental importance of Order for Life’s thriving.

The disordering effects of invasive species has been brought home to me over thirty years of tending a half dozen acres on the western flank of the Shenandoah Valley. I labor to keep under control a variety of invasives (like garlic mustard, autumn olive, bishop’s weed).

(Besides the plants, also problematic in their new ecosystem have been invasive insects —  like the stinkbugs, and before them an alien kind of ladybug, and before them the gypsy moths that were recently wreaking havoc on much of the Eastern forest.)

But my most intense struggle has been what I’ve dubbed “the wisteria wars.” My wisteria turned out to be an invasive form of the vine, continually threatening to upset the ecological balance, growing “out of control” as if it wants to take over the world.

Invasive species can generate disorder as a result of their not having evolved with the rest of a given local natural order.

When things evolve together, they work out the terms for a life-serving order; but when something – with no prior relationship with the rest of the system — enters that ordered world, a destructive disorder can be the result.

A dramatic illustration of this was enacted – more than a century ago — in the eastern forests of North America. The ecological climax of these magnificent forests featured the American chestnut tree. Then people imported some specimens of the Japanese chestnut. Quite innocently — unaware that the Japanese chestnut harbored a fungus that would soon wipe out the native trees.

The Japanese chestnut and its fungus had evolved together for more than 20 million years. Over those eons, they’d worked out a relationship viable for both. But to the American chestnut, the fungus was a sudden intruder. They’d evolved no synergistic way of co-existing. And so this invasive fungus brought down the great chestnut forests of this continent.

The way communities of organisms that evolve together achieve a modus vivendi —a balance that makes the whole viable — is something I like to summarize thus: “The lion and the zebra and the grass collaborate in operating a perpetual motion machine, even as they devour each other.”

The introduction by Europeans of feral cats into Australia is another example of how the arrival of an invasive new element can create ecological disaster. (Invasive predators have contributed to the majority of the extinctions of birds, mammals, and reptiles.)

Occasionally, it is purely “natural” processes that introduce these disordering invasives. New forms of life can be introduced into an ecosystem by washing up on the ocean beaches, or from droppings of birds. Or even – as when the North American and South American tectonic plates collided at the Isthmus of Panama many million years ago – whole different communities of species can suddenly be thrown together.

But the problem of invasive species in our times is almost always the result of human action.

Sometimes people import a new species because they think it will be useful. Sometimes the new species just hitch-hike on some human transport (like zebra mussels introduced into the Great Lakes from the bilge water of ocean-going ships).

As human civilization has become increasingly knit together on a global basis, the sometimes-destructive spread of species into new ecosystems has likewise accelerated.

Which brings into focus the heart of the problem of “Invasives.” The quintessential invasive species is humankind. No, that’s inaccurate: not “humankind,” but the new unprecedented kind of life-form that our species has been developing for mere millennia: “civilized society.”

Human societies, before the rise of civilization, were not so disruptive in this “invasive” fashion. That’s because the societies of hunter-gatherers – which, even before civilization, had spread across the planet – operated in ways that were basically continuous – in their size, structure, and means of subsistence — with the niche in which we had evolved.

Although — even then — we were exceptionally intelligent creatures who created culture, we were still sufficiently in harmony with the rest of the natural order that we inflicted comparatively little damage.

Then came “Civilization,” which can best be defined as “those societies developed by a creature that has extricated itself from the niche in which it evolved biologically by inventing its own way of life.”

That “extrication” and “invention” connects with what was said earlier: how the coming together of things that have had “no prior relationship” can result in “destructive disorder.” Civilized societies — the first kind of life-form not shaped by natural selection but by the creative intelligence of the creature — did not evolve together with the rest of the biosphere.

And the “invasive” life-form of civilization – operating “out of control” has largely taken over the world, reshaping the planet in countless ways.

• As hunter-gatherers, there were only 1-10 million of us. Now, we have passed 8 billion.
• The increasing domination of this invented life-form – civilization – has spread the deserts, and generated an accelerating wave of extinctions.
• This invasive new kind of life-form has now also destabilized the very climate system on which we and the rest of Life-on-Earth depend for our survival (bringing historically unprecedented fires, floods, droughts, lethal heatwaves, rising seas).

Blessings and curses – both the advantages humans derive from unchecked power, and the problems that come from disorder — have marked the course of Civilization from the beginning.