Effectiveness and ethics of using herbicide on invasive species

At The Wilds in Ohio, rhinos are used to control Autumn Olive.

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goats are great for kudzu control. not sure how well they do for other southeastern invasives.

Goats Take On Kudzu at Fort Dickerson Park - City of Knoxville (knoxvilletn.gov)

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@dianastuder ”From a Californian blogger - you are the fire, you are the deer. Prune hard!”

Great thought, that!

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For several years in Florida I was involved in volunteer work to control invasive species. Although Florida continues to be overrun by the particular plant we were trying to control (Schinus terebinthfolius), every plant we eliminated was that much less seed load, and it also preserved some habitat space for valuable coastal native species for a while longer. We used Garlon on stumps after cutting down the brush, and it was very effective. If we omitted the herbicide treatment, the stumps regrew a large plant in a few months. While the volunteers were active, we were preserving some lovely areas of mangrove forests that would otherwise have disappeared. A whole ecosystem seemed to appreciate the effort. Every year the ecosystem is there, is a year the world was a better place - don’t give up.

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LD50 is tested for animals, usually mammals. The toxicity to other plants or pollinators rarely considered.
The ecosystem is complex: when I controlled my woolly adelgid infestation by avoiding seasons when pollinators might be exposed, it also killed off helpful predators of other insects like aphids. End result: trading one infestation for another.

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I had someone do this to a bunch of my beloved native plants I had planted around a place I worked (with permission). They all died. I was heartbroken and it was kinda one of my bosses fault so what could I do? I wasn’t at that job much longer. But that place was a hot mess for other reasons too.

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Nothing like a little Pleistocene rewilding :grin:

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Yes, I thought they were asking if it was safe for them to be around it so much :) I assume they are a human posting on this, at least! That’s what I was answering with the LD50.

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I used to volunteer with an open space agency that managed about 65,000 -70,000 acres. They developed an IPM management plan which included mowing, hand pulling, flaming dicots, chopping and stump treatment, targeted herbicide use and a robust volunteer team. So while one particular area might be sprayed once to knock the invasive population down, it was followed by using other management tools. I am surprised that a state park doesn’t have the same sort of system in place.

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Jena, Germany, chalk mountains. Lots of Orchids! But also goats. Big protest, “the goats are killing the orchids!” So the goats got removed (some decades ago). A few years later the whole area was covered in bushes, no more orchids. So they brought back the goats: now the bushes are held in check, and the orchids returned amidst the hooves of those goats.
Still, every now and then someone tries to get rid of the goats “because of the orchids” …

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Glyphosate is relatively safe. It has been studied a lot, and it’s still used on food crops.
If you use Glyphosate to clear plants, you can use less of it this way:

  1. Cut the plants near the ground with loppers, weed eater, or a mower.
  2. Let the leaves start growing back for a week or three (time depends on season, rain, etc.)
  3. Spray the new leaves with Glyphosate.
  4. A few weeks later, see if anything is left, and kill it if there is (to prevent the creation of “roundup ready” varieties).
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If they use prisoners to hand pull weeds surely that is a better option than spraying herbicides which have a lasting effect of people and the environment??? Would do the prisoners good too. I’ve often thought that people who exploit and damage the environment to make millions (like chemical manufacturers, especially roundup) should be locked away, then made to work at removing weeds from national parks etc.

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We made a well-timed pit stop on a roadtrip and had the good fortune to see this. Quite surprising if you’re not expecting it.

I would agree, as long as the inmates are paid at least minimum wage, and are able to go on to train in such a job if it interests them. And find a job. A criminal record is usually a barrier to being hired. I have heard about inmates in the US who were used to fight bush fires. When some asked if they could make this a career when they were released, the answer was no, not with a criminal record. That is just wrong.

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I think the best way to answer your question “Did I actually make a positive difference?” is to ask if you are doing any quantitative tracking of the management process. You can’t know if you are making a difference if you don’t know where things started and where you stand now. In the invasive species management I help with, we have GPS coordinates for each plant (historical and active locations), survey a few sample plots to track how things are going, and take a photo in the same spot each year so we can see how it looked before the management started and how it looks now.

This documentation showing its effectiveness is irrefutable. Most of the plants we spray now are clearly seedlings, with very few mature clusters being found anymore. There are also much fewer plants being found during each survey/spray trip than in the early years. With the plot surveys documenting the species abundance and also just seeing photos of before and now, it is clear that after hawkweed is killed the native plants come back and flourish. However, just from volunteering a year or two without being taught the history of the project, I might also have thought that perhaps we aren’t making a huge dent. It is so important to see the whole picture when making that assessment.

All this is just to say that I think sometimes herbicides can be an effective tool, but it depends on the species and the type of herbicide being used for that particular situation (disclaimer: we don’t use roundup, so I can’t comment on any of your specific concerns about that one).

However, if you have been there a few years(?) and haven’t noticed any difference in abundance, I think you’re asking the right questions. Without tracking your progress it is hard to say for sure if efforts are just plateauing somewhat or if they have been mostly ineffective for a long time. The herbicide may not be the most effective tool for that particular plant. If what you’re doing isn’t working, you may want to do your own research into alternatives. Have you researched if other agencies/groups/businesses are having success with some other methods for this plant species?

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Very wrong. Firefighters should be highly skilled and well trained. Both for themselves, and for the people they are protecting from wildfire.

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I’m a Land Steward (read Manager) at a small Nature Center in upstate New York, and we deploy herbicide to combat certain invasive in certain locations. I think being very clear about why we treat and how we treat is very important to understand this discussion fully.

First our preserve is small (270 acres) in a matrix of rural, farmland, roads, and power lines. Most of it has regrown from heavily grazed or plowed land, and most of our forested land is on the range of 60 years old. We still maintain some open meadows and shrubland, as well as some leased agricultural land. Invasives are one of our biggest stewardship issues. We have a state rare community on site and a state threatened plant, both of which are threatened by displacement by Pale Swallow-Wort, an aggressive European invader. Additionally many of our open habitats and shrub swamps are being overwhelmed by shrubby invasives.

If we lived in a perfect world we could have swathes of intact habitat that was easy to maintain relatively invasive free, and our stewardship toolbox could include native grazing animals and fire in addition to our more traditional management of herbicide, hand pulling, and mowing. But our preserve is highly fragmented, and despite the great assets we do have there are a lot of problems too.

Our highest priority invasives (the ones that have demonstrated their ability to radically and permanently alter communities, like Phragmites and Pale Swallow-Wort) For these we deploy every tool in our arsenal including herbicide (in places where it’s application is appropriate) our use in natural areas is far less than what is used in our agricultural areas (at 2% spray every acre of agriculture lands gets ~50 lbs of Glyphosate each year) and it is applied in a targeted fashion. The first year post spray of a 100% coverage Swallow-Wort stand looks bleak, but in the follow-up years the problem is much less severe and the recovery is significant. Our herbicide regime only continues because it is effective (both in terms of cost, time, and effect). Monitoring success is critical for deciding how we deploy our limited resources, and herbicides allow us to get a whole lot more effect for the cost.

We will never eradicate established species from our preserve (at least long term) but by staying on top of our worst problems and preventing small problems from getting worse we are reducing invasive coverage, increasing native coverage, and preventing community shifts from radically degrading sensitive areas. Ultimately I view herbicide as a tool. It’s certainly not the only tool we have and just like any tool the way it is wielded is very important to how effective it is. It has negative potential (just like every tool) but in many situations it’s appropriate application is the most effective, lowest cost, lowest off target effects tool we have.

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I worked one summer as a technician applying herbicide in just the way you described. It was hard to feel good about it because of what you have said here: basically, we had a “chemically-dependent” ecosystem, one that will disappear within a few years after herbicide spraying stops, whenever that will be. The native communities you mentioned have only as many years to live as your program can continue; a loss of funding, a disruption in society, and they are gone.

I had this conversation with my manager at that job. I was of the mindset that the ecosystem isn’t really saved unless you can build a fence around it and walk away, and it be able to take it from there; as long as its existence depends on continued intervention, it is like a patient on life support. My manager understood where I was coming from, but she disagreed that that meant it was futile; no, you’ll never be able to build a fence around it and walk away, she said, but her view was more like yours in that the native species can still carry out their ecosystem roles with that help we give them.

In my mind, a species that can only survive with continual human intervention is as good as extinct.

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I hear this and I think about California’s wildfire dependent plant communities, where human induced fire practiced have been in place for thousands of years. The idea that humans are something separate from wilderness and shouldn’t have an impact is an idea that I think is influenced by the abundance of examples of seemingly negative impacts we have had, but it doesn’t have to be that way and it hasn’t always been.

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