there are lots of flavors/versions with lots of alts but basically that the aff re-enforces the human-nonhuman or human-animal divide -- the link, and this creates a bunch of problems -- that's the impact. The alt can range from "adopting the viewpoint of a mountain" to some more radical stuff.
Most links aren't that great; The most common one is a link of omission, which is honestly pretty easy to beat. Link of omission means "the didn't talk about it, therefore they must be anthropocentric" and the common response is "we only have 8 minutes; there's no way we can talk about everything -- We agree that anthro is important, so we'll just perm it". However, there are some better links for sure albeit they're less common to dehumanization and other impacts.
The impacts are generally root cause cards which can also easily be beaten -- There are lots of "proximate cause is fine" or "root cause methodology fails" cards, not to say that these impacts/RC arguments are bad but just to say that you'll have to defend them. Other impacts include genocide, ecological destruction, etcetera.
The alt, as mentioned above, can be viewing something from a mountain which is pretty common, but somewhat susceptible to a link turn. There are others link rejection, thought experiment, etcetera which is probably what you're running.