Animal species will expand into suitable habitat nearby, certainly. Whether they cease to exist in their original range is usually a question of the habitat there becoming unsuitable for some reason or another - maybe through climate change, or increased predation, or because that species has changed the original habitat itself - which is what you seem to be talking about. That is usually a question of overgrazing or similar, and typically will be a cyclical thing: population boom leads to overgrazing, which leads to migration and/or population crash due to starvation, which then allows the food source to recover and rinse and repeat.
I am struggling to think of a particular animal species which has permanently changed the habitat of an area to the point where they couldn’t survive there - other than human. There are plenty of plants and microorganisms though. That is the whole basis of ecological succession.
Mostly asking because this appears to have happened in a fictional world’s ecology (Pokemon, oddly enough), and I have no idea if the concept has any basis in reality.
(In Pokemon, some subspecies seem to have gone extinct in their equivalent of Hokkaido, but some remained extant in the prefecture/region just to the south in-universe)
Yes but it isn’t usually caused just by migration but rather so migration coupled with changing environments.
Changes in the climate are a huge driving factor of this.
Speaking of the Pokémon example, I believe you are speaking of Sinnoh and Johto. Johto is (at least nowadays) a much warmer region than Sinnoh and during the events of the Arceus Legends game, a huge cataclysm happened that is very comparable to driving factors of IRL extinction events. So the migration of Hisui to Johto is not only plausible but actually foreshadowed
I was talking about Sinnoh/Hisui, but the other region I was thinking of was Kitikami (from Scarlet/Violet’s Teal Mask DLC), as white-stripe Basculin seem to show up in the latter’s waterways.
But yeah, migrations between Hisui and Johto might still have happened, considering that Sinnoh still has Sneasel in the modern day, but only the Johtonian subspecies.
If I recall correctly camelids originally developed in the northern tundras (cold desert) before becoming more adapted to mountainous areas and hot deserts. I think there are fossils of camels in northern Canada.
