Let's brainstorm some ideas for some alternate invasive/introduced species and how much of an impact they create on their new environment. Not all of them have to be necessarily detrimental to the environment they're established in, just enough that they're able to maintain a population in a certain environment. Can be flora or fauna. No humans. Some ideas I had: -Perhaps some wealthy French or Italian businessman/woman imports some snow leopards in the Alps or Pyrenees? In the case of the Pyrenees, could this perhaps be an alternate factor in the extinction of the Pyrenean Ibex? Maybe they learn that domesticated/feral sheep, calves and goats are easier prey and create a problem for the local farmers. As they start to become accustomed to their habitat, they spread across and perhaps move into Germany, Switzerland and Spain too. -Komodo dragons in Everglades? -Some stupid bogan living in Queensland somehow gets a hold of some crab-eating macaques and releases them to the Daintree Rainforest. -Perhaps more thought is put into reintroducing bears into Africa after the extinction of the Atlas bear, and some Cantabrian brown bears and/or Marsican brown bears are introduced into North Africa? After all, it was likely that the Atlas bear was actually a Cantabrian brown bear population was introduced to Africa from Spain by the Romans. As for wolves, lynx, bears and wolverines in the UK and Ireland, well that's actually likely to happen quite soon (at least for one or two of the animals; I think the lynx would do best). But if you want, then come up with an earliest possible POD for them to be reintroduced there after 1900. I wonder how well polar bears will do in Antarctica. I mean, there's enough penguins and seals for them to eat there. Now your turn.