The ethics of removing invasive plants

In our area you can get a ticket for removing plants from a public park without a permit or outside of permitted activities, invasive or not.

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Years ago I ran an urban (mostly) river restoration project for a few years. We spent a lot of time and effort planting buffers that were entirely native plants in combinations that would provide a foundation for reasonable wildlife habitat and we spent a lot of time and effort making sure they weren’t overrun with invasive competitors. Japanese knotweed was an issue. Some people were very unhappy when they came across crews stomping down knotweed and there were a couple of confrontations with local landowners who wouldn’t believe that a motley crew of volunteers had any business pulling out flowers (mostly garlic mustard) from a park, even when we had documentation.

Most people loved the project but we were obliged to do a lot of outreach to avoid misunderstandings. It’s a little embarrassing to relate but I actually got into a punch up with three drunk university students I came across vandalising plantings one evening. Don’t like to think about how that would turn out in a place where many people carry concealed handguns. I’m sure that the folks who confronted the knotweed stompers and garlic mustard yankers were as full of righteous indignation as I was that evening, even if they hadn’t actually planted anything.

Anyway, not everybody understands why it’s OK to kill what they see as flowers. I wouldn’t recommend vigilante weeding in public places.

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I’ve been debating the issue with a Joro Spider (an East Asian species) that has appeared in my backyard in Georgia USA (http://www.inaturalist.org/observations/59267584). She is still there after a few weeks and I haven’t seen too many prey items in her web. I debate the ethics of killing it and wonder if it would even make a difference… like draining the ocean with a spoon, as you say. Curious the opinion of others since it is not a plant.

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If I were you I’d prolly just ignore it or maybe take it indoors and feed it bugs for fun (note: nephiline spiders often require vast spaces and supplemental humidity indoors to thrive, please do research before attempting such a feat).

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Off topic: this made me think about Motley Crue doing habitat restoration and this thought is really hilarious :rofl:

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It depends on the plant. I am part of a stewardship group for my park (the City and NCC are landowners but only remove toxic plants such as poison ivy, wild parsnip, and hogweed). We’re overrun with Japanese knotweed so our group trained volunteers to spot and clear it. We tarped some areas with a plan to regenerate in spring. The NCC has now stepped in with a plan. We were actively on the lookout for dog-strangling vine (DSV) that we knew was in the area, and caught it early so that it didn’t seed. It’s still in amongst other natives but again, we have volunteers trained to spot it and remove it when found. If you leave certain invasive species in your park, you’re going to be overrun in very little time, but I don’t recommend doing it alone. Find people who care, that will take the time to learn how to do it correctly.

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In my yard proper I grow for pollinators but my property border has been a tangle of invasives since I moved in 26 years ago. I have pulled and dug and cut away for many of those years and it continues to be a tangled mess with the same species finding their way in no matter what I have done to remove them and of course new species - ampelopsis, stilt grass and lesser celandine are recent interlopers that I have been trying to discourage from taking hold though stilt grass seems impossible to contain. Even not going to work for 4 months I cleared some areas but drop in bucket. Just not sure what good pulling in public does if its not a special concerted effort to rid and follow up on the maintenance - just takes many personnel hours to clear and maintain even a small area. Problem is rampant particularly in settled areas where people nearby plant any and all kinds of unwelcome species.

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Slightly off topic, but this summer Winnipeg had a canker worm infestation, along with more caterpillar hunter beetles (neither of which is invasive). I’d dangle a canker worm on it’s thread in front of a beetle, and managed to feed some that way. It was oddly satisfying!!

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The general rules for the local open space district for which I volunteer are that nothing is to be removed. One of the resource management biologists had commented once that they didn’t want us (docents) to pull out invasives on our own, even knowing there’s a separate group of volunteers who do that work under supervision/authorization.

I can see where some people may get the idea to do that and think they know what they’re doing, but really don’t and might actually pull out a native or rare plant. Thistles, for example, look weedy, but there are natives. And grasses.

Other people may also see someone doing that, even a knowledgeable someone, and decide to do it too, or despite the rules, think it’s ok to pick things.

I don’t know what the other group does in such a case, but it’s not uncommon for me to see native insects using non-native plants, caterpillars or chrysalis on thistles at those times of year (but then, I look for such things).

It depends on where you are, and how knowledgeable you really are.

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If only it was like that with Himalaya blackberry in Washington State!

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It’s still all over the place though, at least near towns & cities. I doubt that many people have been taken to court over it.

Knotweed only spreads by vegetative means here. I assume the blackberry sets viable seeds?

An interesting flip-side to the question might be, “What are the ethics of not removing invasive plants?” The problem is (at least in CA, but I suspect in many other places as well), there are highly invasive plants which can be identified and removed by the proper agencies, but there is a lack of knowledge, funding, resources, and education on the part of public and private agencies alike which precludes “nipping the problem in the bud” before it’s too far gone to manage.

That being said, it’d be irresponsible not to mention that ID confidence needs to be at a very high level, ideally confirmed through multiple observations of the invasive species during flowering to confirm to the species level.

One person earlier in the thread brought up a very good point about native thistles (at least in CA), where there may easily be confusion between native thistle (Cirsium brevistylum and others) and invasive Cirsium or even invasive Carduus by those less familiar with native thistles–some Californians aren’t even aware that there are native thistles, so this is a great example of where good intentions could be very harmful to native species!

For me, do no harm always comes first, but if I see invasive french broom (Genista monspessulana) in an area I frequent at a monthly basis, 9 times out of 10 I’ll do a quick look around and pull or break the stem if I can, replace and pack down the disturbed dirt and come back in a month or so to get any seedlings or plants I missed.

This is where the ethics of not pulling out invasive exotic plants comes in, since Genista is a highly invasive (and highly recognizable) plant which can easily take over an area by spreading thousands of seeds a season, choking out natives, and greatly increasing fire risk, and reducing habitat value for endemic plants, birds, insects, etc.

Ideally, I’d get permission and go through the proper channels, but as another person in the thread mentioned, this can take a while (though I am getting more interested in doing so in areas which are more thoroughly managed). This might be the best idea, in terms of getting trained and organized ‘weed warriors’
to work on removing invasive plants.

I get the idea of ‘a drop in the bucket/ocean’ echoed by many in this thread, but, and not to be cheesy, it’s important to remember that the ocean is nothing but a collection of individual drops, so again, in my mind it’s always important to consider the flip side of every argument.

It’s a thorny issue, the solution or answer to which is probably as varied as the number of unique circumstances and ecosystem contexts that exist!

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Also off topic: A phrase I never thought I’d see.

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I somewhat wonder if this topic varies from place to place - I feel the Idea of preserving a local flora and fauna to be more prominent in places that are relatively new to human influence, like the Americas or Australia. In central Europe, after thousands of years of humans manipulating floras we are a point where it seems impossible to determine whats native and what’s dragged across the various mountain ranges and oceans. Let’s take Digitalis purpurea - it has survived the last Ice Age in Spain, and quickly followed the receding glaciers back all the way to Scandinavia - through populated country. Who’s to say if that was natural, or human induced, or a positive form of invasiveness? In our densely populated area, you can be happy about any plant surviving, especially with the new effects of a changing climate.
Yes, there are some severe problems - but those extremes can’t be battled with occasional pulling: Giant Hogweed ist too dangerous without proper equipment, Impatiens glandulifera has to be found before the first seed capsule is ready to explode, and Japanese Knotweed? leave a cm of root in the ground or, worse, allow it to drift down the stream, and you’ve multiplied the Problem.

I personally see biodiversity as a meta-stable system - in the long run, stopping the flow completely can be just as problematic as a dynamic take-over.

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It may. I have wondered that as well. I am a US citizen and resident and consider any species that did not exist in the Americas prior to any European contact to be an exotic. I think since we are talking about only 550 years with early documentation of the existing flora and fauna on the continents, it may be something easier to determine than would be in Europe, for sure.

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Also easier to decide (if not to do) for us in the Southwestern Cape, where we have a mediterranean climate and an entire floral kingdom. Is it fynbos or invasive or commonorgarden or…

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Right, but that is a different kind of exoticism. @pmmgarak was speaking of the postglacial expansion of plants within Europe, and whether it was natural or human-assisted. Similar questions can be asked of postglacial North American plants – like the oak savannahs in the Pacific Northwest. Native people maintained the open savanna by periodic burning; but some suggest that they may have transported the acorns, as well.

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Actually, I was considering both effects - we ARE part of the ecosystem so how natural or unnatural are our influences? As for the Americas: Not just the crops, but also ornamental species like Tigridia pavonia or Mirabilis jalapa have already been spread by pre-European civilizations - the latter one so much that the true origin of the species isn’t clear.

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While humans are part of the environment, it’s important to remember that it is not the first time in natural history that a too-successful group of organisms has so dramatically and quickly transformed the landscape/climate of Earth as to doom themselves – and the majority of species diversity that existed in the epoch – to extinction.
As a thinking species we ought to choose to make our influence one that promotes realtive stability. For our sake at least.

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In some cases if not done properly the results could be detrimental.
Example: Lygodium japonicum-one could easily spread thousands of spores.

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