Native species are just an invasive species 10 000 years later.

Ok, so in the year 11950 we can have a debate about whether or not a species has been around long enough to be considered native. Right now, they're still invasive.

Who gets to decide what is "harmful" and what isn't? Why is it necessarily better to have one animal species in a certain area rather than another? Valuing native species over invasive species seems like an arbitrary human value judgment. (I don't necessarily disagree with eradicating invasive species, but I've noticed that people often haven't thought it through or considered their biases.)

Why, you get to decide. And I do. And everyone else. Just like we all chose whom to listen to. Turns out that people who study these things and understand the implications tend to be more listened to than, say, me, because I'm not an expert.

But to explain a bit of the reasoning, as I understand it, invasive species are considered harmful to ecosystems because they tend to throw them out of equilibrium. If you introduce something to an environment with no natural predators or other environment feedback loops to constrain population growth, the newly introduced species has a field day, for a bit, until it kills off whatever it feeds on. Since ecosystems are inherently deeply interconnected things, the boom-bust cycle causes all sorts of problems.

Now maybe a new equilibrium is eventually "better" than it was before, but that, I think, is the real arbitrary human value judgment. Observing that introducing a new species throws existing systems out of whack isn't a value judgement - it accurately describes what happens.

But real world ecosystems are never in equilibrium, at least not for long. Even isolated ecosystems with little human contact and no invasive species experience boom and bust cycles. So we're actually just discussing the appropriate rate of change. How fast is too fast?

I don't think ecologists use the word the same way you do. I'm not an ecologist; I just used to date one. But I do know that equilibrium in the ecology sense is not static at all.

If I'm understanding your comment about the rate of change, I think you're talking about drift between equilibria.

Asking about "too fast" is where the human value judgement comes in. Which isn't invalid, it is just human-centric and far from the whole picture. Stating that introducing an invasive species can destroy the existing ecosystem is a statement of fact without judgement. It is just an observation of reality.

>Who gets to decide what is "harmful" and what isn't?

Typically zoologists, botanists, and other biologists who study local ecosystems and determine the damage done by invasive species.

Construing this as a human concept doesn't make it arbitrary - anthropogenic impact on the environment is important because we rely on our environment for survival as a species. Damage isn't limited to just a less biological diversity, it can and has stretched into agriculture and human production.

Reminds my if an old timey sayjng—"A weed is just a plant out of place."

And back on topic - Kill 'em all - native, invasive, makes no difference. As I read the expert concensus, after eradication the likelihood of some edge case eco-dependency being revealed should be vanishingly small, whereas the status quo allows millions of homo sapiens to be sickened and or killed.

That seems like easy math to me.

NB: I'm a Southerner (Peach state) so I'll admit I carry a strong, but well earned, hatred of the vile creatures.