[soiltype]

Rare is relative. Those changes all happened over much longer timescales and with far fewer species involved in a given ecosystem. It's not the same thing as what we're doing. You're making essentially the same argument as "Earth's climate has always been changing, what's the big deal?"

The big deal is that when a species becomes invasive, the effects can cascade. You don't just lose their direct competitors and their prey, you can lose anything they pollinate, nest in, are nested in, etc. You can replace a diverse ecosystem with a near-monoculture.

Of course, if you don't hold the fundamental belief that biodiversity is Good, and is Better than raw biomass increase, I see why this doesn't bother you, but I do hold that position.