This summer I’ve been on a mission. My objective: eradicate from our 96-acre farm some of the invasive plant species. I’ve been hacking, slashing, cutting, chopping and smothering garlic mustard, goutweed, European buckthorn, European barberry, phragmites (said to be the most nefariously invasive plant species in Ontario), and other alien species.
When I took up the task, my concern as an amateur conservationist and ecologist was primarily biological and to a lesser extent economic. I am aware of how invasive plant species can seriously damage, even irreparably harm, native ecosystems which I believe are richly valuable in themselves and need to be protected. Garlic mustard, a herb imported from Europe, will spread into wooded areas and displace native wildflowers, including Ontario’s provincial wildflower, the trillium. European buckthorn, a small tree originating in Eurasia, also spreads rapidly and crowds out native tree species. Phragmites, another European transplant can destroy huge swaths of native wetlands affecting all the native plant, animal and insect species that call them home.
To step away from plants for a moment, the emerald ash borer beetle is marauding through the province’s deciduous forests killing white ash trees and costing millions in lost lumber revenues, an example of the potential economic impact of some invasive species. Collaterally, forest biodiversity is being adversely affected which may also result in yet to be realized economic costs. Agriculture, too, is in the cross-hairs. The aforementioned buckthorn and barberry, for example, are said to be vectors of diseases that can damage soybean and wheat crops respectively.
Comments by two Facebook friends in response to a post I shared about my clash with invasives prompted me to think more deeply about the phenomenon of invasive species and do some research. One friend somewhat forcefully took me to task for messing with Nature, his point being that Nature is continually evolving and will sort itself out, thank you very much. Another, an Indigenous mentor, said something similar but in the context of “All my Relations” (Mitakuye-Oyasin, Ojibwe for we are all related, humans and all things of the land). She was speaking of her faith that the “Creator” would determine Mother Nature’s composition without any interference by us humans.
I found both comments arresting, especially the one by my dear Indigenous sister, which I take very seriously. I came to realize that, for anyone interested in ecological and conservation sciences, the approach to invasive species cannot simply be determined by an understanding of biological and economic impacts alone. The associated social science as well as Nature- or Spirit-related belief systems also should be considered.
Some scientists, too, now argue that we should be more welcoming of the evolutionary diversity that can be generated by species invasions, treating it as a hallmark of the Anthropocene, the geological era in which we live. While this idea is controversial, it seems true enough that the range of species shifts resulting from environmental change and other factors make the distinction between native and non-native species much less clear than it was traditionally. Species can move taking some of their ecological network with them, but “rewiring” it to include some new species as well. The extent to which this can be seen as an invasion, therefore, is perhaps debatable. Maybe those of us who seek to eliminate non-native species are the real invaders.
So I now find myself considering the phenomenon of invasive species on several coinciding and perhaps overlapping fronts. Included are the complex politics of how decisions are made about management programs. For example, some municipalities spray phragmites with powerful herbicides. In places where this tough, insidious reed grass has colonized massive swaths of native wetlands, and where uprooting or smothering the plants is not a practical option, one can perhaps understand this choice of approaches. But many ecologists and conservationists, citizens too, strenuously object to such practices because the chemicals used are believed to kill other species – plant, insect and possibly small animals. This is the case with the broad spectrum herbicide, glyphosate, which also is thought by some scientists to be a carcinogen.
The psychology of how people view different types of invasive species is another factor. Domesticated cats, both loved and loathed, are a good example. A 2013 study estimated that free-ranging domestic cats in the U.S. cause the deaths of 1.3 to 4 billion birds yearly. That’s right, billion! It’s a statistic that, not surprisingly, can pit bird enthusiasts against cat owners in highly emotionally charged arguments.
The Spiritual dimension articulated by my Indigenous sister also, I believe, deserves elucidation and consideration. On that subject, though, I’ve got to do some more thinking and will rely on the “Owl Woman,” as she is called, to guide me.
The debate on invasives is obviously far more complex and ranges far more broadly than does my preoccupation with a few non-native plant species on my property. I will continue, even ramp up, my efforts to manage them (“eradication” which is the aspiration I began this column with is, of course, pie in the sky). So garlic mustard, European buckthorn, phragmites – you will get no quarter from me, at least for now. But I will also continue to educate myself about the social, psychological, and Spiritual as well as the biological and economic impacts of this beguiling and somewhat alien field of study and debate. ◊