Unfortunately it's very hospitable to the vast majority of smaller animals since it doesn't get very cold on the south end of the island and there's a fair amount of food available. Rats live comfortably outside of cities here, and you'll find them out in the woods where they can eat insects, seeds, nuts, berries, etc for most/all of the year.
British Columbia has banned rat poison since around 2021. At least anecdotally, the impact on the local rat population has been exactly what you'd expect.
It's difficult to assess one way or the other, but the impact of poisons on rat-eating animals was bordering catastrophic in some areas. Farms using rat poison would often have dead raptors nearby, for example. Hopefully the predators not dying from poisoning will have its own effect on the rat population. It might not be as significant as poison, but it's better that we have healthy predator populations rather than eventually little or none.
Alberta's advantage is being landlocked (and not a natural habitat for rats). They managed to keep the rats that arrived at the ports from encroaching inland.