The case *against* killing spotted lanternflies?

I really haven’t heard about any impact to crops other than vineyards.

My sense, after watching this develop over a couple of years, is that the impact of SLF on our native plants and our crops (besides vineyards) is not going to be remotely as great as people are making it out to be. I think we are probably wasting a lot of attention and energy on SLF, when there are bigger threats to our native ecosystems that we’re ignoring. In my area, I think the biggest threat is deer over-population. Until we deal with that, there’s probably no point trying to remove the invasive plants that dominate the understory of the forests around here (Essex County, New Jersey, USA)


In this case, I think there’s an important difference when you factor in management.

More diverse systems are sometimes more stable than less diverse systems, but it matters how the system is supported. If it’s self-sustaining, it’s legitimately strong, but if it’s artificially supported by humans, it’s not. Humans, and our political, financial, social, and religious systems, become the weakest link. Instead of being built on a foundation, they’re built atop something far less stable.

Generally speaking, weak monocultures are those that rely on near constant human management, and threaten systemic harm via bottom-up trophic cascade because of their failure to survive: Agricultural crops and trees planted for forestry purposes. These monocultures are vulnerable to attack by a diverse horde of higher level trophic occupants and the pathogens they carry. The endangered species act basically incorporates listed species into this model of artificial human support. Works well with things like DDT, deforestation, pollution, hunting; things humans do directly. Not so much with managing other species to support target species. But back to monocultures:

Organisms that have evolved to form monocultures are typically successful and resilient. I can name the following highly successful invasive aquatic plants off the top of my head:

Phragmites australis
Typha angustifolia, and T. x glauca
Phalaris arundinacea
Lythrum salicaria

In contrast to things like crops, they threaten bottom-up trophic cascade with their very presence. They need no management to accomplish this, and while doing so, they defeat that same diverse horde of enemies.

The success of these invaders kind of turns the whole “diversity is strength” thing on its head. Diversity may in fact be a weakness. @Marina_Gorbunova

I’d imagine the response will be something like “But those invasives became established due to human disturbance!” except that I don’t think that’s true in this case. Hydrology, floods, tides, fire, and other natural processes create more than enough disturbance.

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I have conflicting information as to whether the eradication of Aedes aegypti from Brazil in the early 20th century was successful or not. Although it needs to be said: if it was eradicated then, it has since re-invaded.

Doesn’t matter how they got there, but they evolved in a different place, thus nothing around them now is adapted to them and established weeds usually have major + about them that helps them not only survive in a new place, but also win in competition.

Yes, but that also means they haven’t evolved defenses to the herbivores and pathogens in the new area, either. Theoretically, it should be a level playing field.

As far as pathogens go, I know that viruses tend to be specialized, but bacteria and fungi should be the opposite.

Perhaps I should have ended with screwworm and a note clarifying that, while not an invasive, it’s still an example of a concentrated effort - through Sterile Insect Release Method - that lead to the eradication of an unwanted insect species.

Bacteria and fungi on plants are also specialized if you check hosts of them, usually they can jump between species of the same genus. Invasive plants if we look at them always are in good place for that matter, either very agressive annual plant with tons of seeds or perennial plant that is very hard to kill because it has rhizome or it grows easily in any place (so likely chemically affecting plants nearby). Take Elodea canadensis that can grow from small piece into a full plant and even though it has 2 sexes, only was is present here, but it didn’t stop it from vegetatively colonise everything it can. You rarely see any miners or gallers on such plants, usually it happens if, again, there’re a native species of the same genus or it was brought with the plant from where it originated. Herbivores aren’t a danger for such plants and tbh for most plants, big mammals just can’t each and every sprout (and they can be toxic), small ones also rarely target them.
To kinda prove my own experience here are introuced plant observations of mine, you can see how rare it is to fin anything wrong with them, especially matter fall observations where most plants suffer from something.

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In regards to biodiversity, I think there’s a definite disconnect in this thread between just how severe people are judging our current ecological crisis. Generalists and species that are already anthropogenically adapted are far, far more likely to survive the next 10, 20, 30 years than any other life form on the planet. Our classical understanding of biodiversity preservation is not going to do much than delay the inevitable by maybe a decade at maximum.

What should be done about it instead, I don’t claim to know with perfect certainty, nor can I offer suggestions without brushing up against this forum’s rules, but I am usually inclined to think most problems are best tackled at the source (i.e. major causative agents of climate change), rather than treating the symptom (mass extinctions) ;)

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Monocultures exhibit only temporary strength, while diversity offers long-lasting strength (even as that diversity evolves over time). A monoculture is susceptible as soon as one thing is able to exploit it. A diverse ecosystem does not have this susceptibility because there are multiple species providing checks and balances (parasitoids keeping caterpillars in check, who in turn keep vegetation in check). Do things cycle? Sure, we can have a boom year for tent caterpillars, but that is almost always followed shortly after by a boom in tent caterpillar parasitoids/predators. A monoculture of Phragmites australis seems strong until a fungal disease spreads rapidly through it and there are no other plants to quickly fill the gaps before serious erosion sets in.

As you yourself pointed out, the reason chestnut blight didn’t cause the collapse of eastern North American hardwood ecosystems is because we had other native mast trees that helped compensate.


I think the hope is that we can preserve some diversity long enough for us humans to get out s*** together. We are having an impact on even generalist species. For example, many Icterids are generalist and easily exist and forage in urban areas, and yet we are still seeing large population declines.


My $.02: Morality always traces back to “because it is bad”. We have moral intuitions. By default we assume they are true as a matter of objective fact. When we try to find a basis for our moral intuitions, though, generally two things happen: there’s still a “because it is bad” hiding in there, the most we can really do is pile words & layers of analysis on top of it and hope people don’t notice that it’s still there; if we keep working at it long enough, we’ll eventually notice that the “foundation” for our moral intuitions changes a lot more than our moral intuitions do.


(post deleted by author bc author reconsidered his choice to wade into this discussion)


Actually … no.

Biodiversity provides humans with very tangible benefits and resources. Crystal clear water from the Highlands; Optimal mix of nutritious forage for game and livestock; honey with just the right tang and sickly sweet aftertaste; good quality firewood; Shrubs with fibrous leaves for making textiles

These and tonnes of others have a single thing in common - You have biodiversity to thank for them

And although many scientists and futurists would have you believe otherwise, we are still EONS away from being able to replicate the processes and reactions that give us such things as an end product


That Life, capital L, will survive with lower biodiversity is not the question at hand. That probably the survivors will be generalists is also most likely true. That Life will survive sidesteps the moral problems of of biodiversity loss. It also assumes that a biodiversity crash will not affect us, as generalists. There are a thousand scenarios where life becomes untenable for human life. The great generalists could be nematodes or tardigrades. It could be this kind of attitude that dooms intelligent civilizations, and why when we search the sky for neighboring civilizations, we hear nothing.

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Now I’m imagining a great city built by civilized tardigrades.

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Spotted this taped to a tree at the trailhead yesterday (Niagara Region, Ontario, Canada).

(Might be nice if they figured out a way to make these legible!)

Indigenous to China, then accidentally introduced to South Korea, then Japan, then the East Coast of America. Niagara has extensive vineyards and orchards, so I’m thinking a lot of people here are following the American invasions very seriously, and with quite a lot of anxiety.

So far, no iNat observations in the province. But just nine days ago there was an observation in Buffalo. It’s really just a question of time, I think.

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more mixed messaging in popular culture about killing SLFs:

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The real problem is that the two hybridize creating Hybrid Cattail which outcompetes both straight species.

Why is that a problem?

I realize the brief question sound kind of combative – I don’t know anything about cattail ecology and am asking sincerely!

That is native to Eurasia too.

Hybrid Cattail is likely a boon for species that like cattail marshes (e.g., Red-winged Blackbird, Black Rail). The problem is hybrid cattail not only outcompetes its parent taxa, it outcompetes other native wetland plants as well. It can tolerate a wider range of water depths and salinity than either parent taxa. So it can create huge monocultures. This means lower plant diversity and lower animal diversity (despite the fact that a select few species may thrive with more cattail marshes).

I suspect Hybrid Cattail functions as good as or better than its parent taxa in remediation wetlands. But that’s not my area of expertise.

You may enjoy this article.

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