When faced with invasive, non-native weeds on the range, the first response for many conservationists is to load up a backpack sprayer full of pesticides.
Spraying chemicals toxic to wildlife and people — under the auspices of protecting wildlife and people — is often portrayed as a necessary evil if we want to stop the spread of invasive species.
But what if such spraying doesn’t actually work?
A 16-year study recently released by the United States Department of Agriculture found that spraying herbicide doesn’t always pay.
The study, on the USDA’s Agricultural Research Station in Miles City, Montana, found that spraying for invasive leafy spurge had quite different results than intended:
“A one-time aerial spraying of herbicide showed that the invasive leafy spurge (Euphorbia esula L) may have ultimately increased due to spraying. Conversely, several desirable native forbs were still suffering the effects of spraying 16 years after spraying.”
This is just one study, of course.
But it begs the question: Should the first impulse of conservationists be to spray herbicides and other pesticides to control invasive species? Are such efforts really working?
Spraying pesticides for invasives control has long struck me as one of those cases where “the cure is often worse than the disease.”
Perhaps the real issue here is humanity’s relationship with non-native species. Too often, conservationists appear content to label all non-native species as “bad” and thus seek to eradicate them by any means necessary.
It’s time to face up to the reality of the “invasive species” issue: It’s complicated.
The rapid spread of invasives may be a symptom of deeper ecological problems, not the problem itself. Thus, using chemicals is only treating the symptom, not addressing the real issues. I’ll refrain from making any comparisons to U.S. health care.
In other instances, invasives may be so established on a landscape that we can only hope to manage them, and eradication attempts will be proven folly.
Complex conservation issues deserve complex solutions. Spraying too often feels reactionary rather than well thought.
Spraying does involve action, and action often gives the illusion of accomplishment. Weeds wilt and die. Maybe they even disappear (for a bit).
Certainly, there are incidences where spraying is effective conservation. In the remote canyons of Hells Canyon, for instance, helicopter surveys can reveal small, new weed infestations.
Here, Conservancy crews spray the weeds before they become established. If those weeds spread, they would damage wildlife habitat and become almost impossible to control. Thus, by spraying now, there likely will be less need for more spraying later.
That’s strategic. Many pesticide applications in invasives control, I am convinced, are not.
Too often, conservationists have been spraying first, asking questions later.
It’s time we take a long, hard look at our use of pesticides, and quit using them when the only measurable outcome is increasing toxic chemicals in our land and water.
(Image credit: Matt Miller/TNC.)