Quite a few things.
1 - People are going to be aware that the ecology can be damaged, unlike in UO where that wasn't even a thought any of the players had.
2 - scale. The maps here are HUGE in comparison to UO. the size of the world will mean that It'll likely take a concerted effort on the part of many people to wipe out an ecology, and they would also have to work against other people who are trying to save the ecology. Not to say that it won't happen, but it'll take some deliberate effort.
3 - Ecology management will be a focus effort during the Alpha and Beta, depending on testing SbS will tweak the plants and animals to either be easier or harder to propagate and kill.
4 - if it happens there is probably some Story Engine stuff that is planned for said ecological events. So while it might suck for where it happens, it'll lead to some interesting events and who knows what the Story engine will do from there.
This Video has been brought up a few times before, but every time it is there is usually an interesting discussion about it.