Just make sure you're reading resources that don't have an obvious bias (I'm looking at SeaWorld here). That can be hard, because both sides will have a bias. I'm actually not aware of any reliable resource that is completely neutral on this topic. I was actually asked about SeaWorld/Blackfish at UF, but I also feel very adequately informed on both sides. If you don't feel informed about something, try not to feel like you need to blurt out an opinion. I think the adcoms expect you to have some working knowledge about most hot topics in the field. Explain what you know and how you feel about it, but also explain that you feel you need to learn more about it to form a more educated opinion (if that's the case). Part of the problem with controversy is that too few people seek out knowledge before forming an opinion. As veterinarians, you may be approached with questions about controversies, and you'll need to know how to handle that.
Your state's DNR could be good for invasive species if you're not even sure which species in particular are an issue. That's also a good place to read about nuisance species (species that people seek to kill year round, even if they are native). Read up on conservation efforts for species that are in trouble. I've been asked "But why is it okay to kill of invasive species? We're supposed to reduce suffering and promote health. Why don't invasive species not apply here?" The knee-jerk reaction is to say "Because they're killing off other species via competition" or something, but I personally think it's much harder to answer (again, my opinion).
OneHealth has a website.
This is just my opinion, but SDN (or any forum) isn't a source you should use to form your opinions. Most of what you'll see on here are opinions about something. There's a good amount of pressure here to agree, or you'll have to argue with a handful of people to defend your POV (especially when something is a pretty hot topic and a lot of people get involved). There are many cases where some people just have a lack of facts/experience and have formed opinions that don't make any sense, but that's a little different. You can definitely learn a lot from posters on here, but you are entitled to forming your own independent opinion regardless of what someone says to you or about something on a thread you're reading. Plus, if you just repeat something that a poster on here has said, you'll probably dig your own grave if someone presses you even more and you're out of words (I've heard someone drop near-identical quotes of SDN stuff, and they were most certainly not the OP). I'm not saying you'd do that, I just think it's easy to want to take these opinions and run with it.