The only animal that I know of that changes their habitat even close to us humans are beavers. I've seen entire mountain valleys carved out into one beaver pond after another, which made for great hiking and very muddy boots. I've never BATed before, but I would make an entire set in individual pieces to match the PEG Pond and Steam kits.
Beaver Lodge
Beaver Damns
Tree stumps from beavers felling the trees.