We received a comment on our Research with Pre-Emergence Herbicides, Native Plants blog post and felt it was such a great question, that our response should be shared in it’s own post. Read on…
“Will you also be monitoring effects of herbicide on other native species: arthropods, birds, reptiles, etc.?”
This is an open-end question and I could spend days addressing it. With any pesticide, there are good and bad consequences -you must weigh the benefits with the potential side effects. Herbicides are suppose to impact plants only; however, there are some instances when herbicides can be toxic to plant pathogens or arthropods. Some herbicides can also change the feeding behavior of insects. There has been a lot of talk about the most commonly used herbicide in the world, glyphosate (A.K.A. Roundup), and it’s impact on frogs. But something else is often over looked. Pesticides are made of an “active ingredient” (the poisonous component) along with “other ingredients”. The “other ingredients” are patented secrets and we don’t always know what is included in the herbicide. Pesticide manufacturers want their product to be as effective as possible and they do that by adding adjuvants or surfactants. The role of an adjuvant or surfactant is to increase the penetration of pesticide into the target organism. The idea is the more pesticide the target organism receives, the better it works. Unfortunately, the EPA only requires testing of the “active ingredients” and not all the “other ingredients”. Sometimes these “other ingredients” have detrimental effects on non-target organisms.
Another potential side effect of herbicide is the consequence of removing existing vegetation. Many insect-weed studies have shown that the removal of weeds, by hand or chemical, has an equal effect on insect populations. It is likely the same outcome would be detected for birds or other seed specialists, as well. The big difference is that applying herbicide to 1,000 acres is much easier than hand removing weeds in such a large area.
With all that said, with this experiment, we are looking at only one herbicide and 6 native plant species. We are conducting this research in greenhouse-like conditions that don’t lend well to examining side effects on other organisms. We would have to conduct a targeted study (like this one) that did specific assays examining the effect of an herbicide on tiger beetles.
-CSR’s Senior Scientist, Kelly Tindall
Conservation Seeding & Restoration Inc is not an herbicide spray company. The services we offer do not revolve around chemical applications, but rather the restoration of native plant habitats. When we do use herbicides we treat weeds only so that native grasses and plants can establish themselves and out-compete weeds for water, light, nutrients, and space.
Filed under: Biology, Stewardship Tagged: | Herbicide Application, native plants, Tiger Beetles, weed eradication
another disadvantage of herbicide: it’s good for business, and is a good money maker.
I would be curious about the effects of herbicides on the native soil organisms that could potentially sterilize and or create a less conducive environment for native grasses? Also curious if there is perhaps a larger picture of weeds benefit to an area…as in knapweed helping recondition soils in 5-8 years with deep taproots and then clearing the way for the next succession of plant life? Or the nitrogen fixing of scotch broom after a clear cut, or the band aid like qualities of blackberries on logging roads. Or the plant indications of abuses in livestock operations. “Invasion Biology, Critique of a Psuedo-Science” and “Invasive Plant Medicine” books worth looking at?! Appreciate your efforts to limit herbicide use, but in my radical opinion, feel like enlightened companies cease to support big chem companies entirely, who usually are beholden to the bottom line, not the life of the land and have proven this time and time
again. Aloha.
Thank you for your comment regarding herbicide and native plants, CSR’s Steven Paulsen responds:
“Stewardship is the act of promoting a landscape, Maintenance is the act of keeping it in stasis” ~Steven Paulsen
would be curious about the effects of herbicides on the native soil organisms that could potentially sterilize and or create a less conducive environment for native grasses?
In the case of herbicides as a general class of chemistry it is very difficult to say anything with the idea of an absolute. In most cases particularly with the chemicals we typically use the breakdown of “active ingredient” in soils is very rapid. Ironically the breakdown/binding is due specifically to the micro organisms in the soil. It is my experience that unless the applicator is working away from the label, damage to soil is not likely.
Also curious if there is perhaps a larger picture of weeds benefit to an area…as in knapweed helping recondition soils in 5-8 years with deep taproots and then clearing the way for the next succession of plant life?
The idea of leaving knapweed to its own ends for a period of 5-8 years is troubling at best. Away from so many reasons not too, I would consider the reality of walking past not the action of a land steward but the action of a lazy maintenance man. The potential for the plant to be persistent for many lifetimes coupled with the displacement of all the players that would otherwise occupy the space is in my opinion unconscionable. As with many non native plants a personal choice is dealt to the landscape with regard to how it is ultimately stewarded. Peoples desire/needs dictate the results, it is my opinion that humans should ultimately steward and foster diversity this unfortunately is not the easiest path.
Or the nitrogen fixing of scotch broom after a clear cut, Why not native aspen?
or the band aid like qualities of blackberries on logging roads. How about native diversity in early serial plant succession?
Or the plant indications of abuses in livestock operations. “Invasion Biology, Critique of a Psuedo-Science” and “Invasive Plant Medicine” books worth looking at?! I am unfamiliar with both of these volumes and will look into them thank you for the reference.
Appreciate your efforts to limit herbicide use, but in my radical opinion, feel like enlightened companies cease to support big chem companies entirely, who usually are beholden to the bottom line, who usually are beholden to the bottom line. Business, especially for profit businesses in the environmental arena and more specifically in the restoration application arena, simply must be beholden to the bottom line. If we cannot justify our cause with value driven concepts of carefully crafted and guaranteed delivery we are nothing more than concerned folks walking about hoping for things to get better and wishing to not be held accountable for and to our actions.