"Apparently, predatory vines and giant rats. But it's not a place we want to mess around with, because we are depending on it for the oxygen, and we have no way of regenerating it if we accidentally kill off too much. Just keep the vines back from extending out of the Gardens, that's the best we're doing right now."

[Jack anticipates the objection.] "I don't really like it, either, but, as I keep somehow mentioning, alien botany's not my specialty. Or anyone's on the Station so far, really."