Climate change is particularly scary for those of us doing conservation in very fragmented landscapes, because you're essentially depending on having sufficient north-south connectivity so that species can migrate north as they need to. When you're dealing with a fragmented landscape, if those connections are broken, there's a pretty good chance those species won't be able to move quickly enough to survive.
At a conference a few years back I saw a presentation that looked at modelling different vegetation communities. The modelling showed that, essentially, new communities would be created that didn't even exist then. Ultimately, we have no idea what the species complement will be, and in turn, we don't know what types of wildlife those different habitats will support.