An introductiry tutorial or some more info (movement range of animals etc) would have been nice. But it's clean and simple enough to get a grasp on it by trial and error.
And after about 3 or 4 turns I can't seem to place a block, and I'm not sure why. It usually happens when I've isolated some rabbits/foxes on an "island". Possibly a bug when there are no rabbits in reach?
The idea is very nice though, I love these kind of 'ecosystem simulator' games, and I wish there were more of them.