This world takes place in the remains of the Eastern United States, devastated by 3000 years of neglect and climate change. The Mississipi river is pretty much a gulf now, which has caused everything east of it to either sink, or become part of several new islands.
http://www.floodmap.net/?ll=20,-10&z=3&e=225 was used as a resource to help me with drawing maps.
So, while I have not created a definitive biome map, the islands that were once the east coast are much more lush and jungle like, as are the Great Plains, which are now more reminiscent of true savannahs, though some parts in the west have desertified, and a lot of the coast is swampy mangrove.
My question is, what actually lives here? The mutant apocalypse that destroyed this world was in the 2200s, and before it occured, there were many attempts to clone extinct and endangered animals, some of which were successful, though the extinct specimens were primarily kept in zoos.
The first thing I thought of was jaguars, as they once inhabited the US-Mexico border before they were hunted back to South and Central America. After all, they'd be better suited to a tropical/subtropical climate than their primary competition, which would obviously be Coyotes and Mountain Lions. They would have either headed north due to the flooding of their previous habitat, or been cloned by the Helix Corporation, which inadvertantly caused the apocalypse.
Another thought was Rhinos. Helix originally gained prominence by cloning several species of rhinoceros back from the brink. They would definitely be suited for the tropical grassland that was at one point called the Great Plains. Of course, they would have to compete with cloned bison. Also, mutants ate a significant portion of the cows. I figured that after the destruction of civilization, animals in zoos and other such care facilities would have maintained breding populations provided they weren't eaten by the Biters, most of which were exterminated anyway. They only would have survived, because at the time, most of these facilities were automated by domestic robots and AIs. Chances are, the animals capable of surviving in their new environment managed to survive, but what would these animals be?
So, I'm not an expert on this sort of thing, but I'm hoping someone else on this site is, so what would new species would survive and what old species would die out in this new North America? My list is various South American, South Asian, and African animals including jaguars, monkeys, and possibly even elephants. This is just to give my world an exotic touch, as the whole thing is meant to be a sci fi twist on fantasy tropes, but I didn't want the stereotypically North American-style environment.
EDIT: I recently discovered various plans to restore the pleistocene ecosystem to North America. That could theoretically be my excuse, though there wouldn't be any rhinos or monkeys...