Were they introduced to the west by humans? If this migration is occurring without human intervention this is just evolution doing its thing.
Itโs going to be hard to remove human influence on this equation considering almost everywhere the human influence is present.
Agreed, I think a lot of conservationism can even go too far in removing or preventing natural adaptation to the human presence. I was mostly referring to cases where humans can transport species between local ecosystems in a way that wouldnโt occur otherwise, which can result in an environmental imbalance that doesnโt always fix itself since such changes in range donโt usually occur naturally on a scale as large as with, say, the introduction of the brown marmorated stinkbug into North America from Asia.
