I don't see why they would'nt leave it up. It was the absolutely perfect way to show the zoo's legacy of their semi/somewhat/success story of saving a rhinoceros species. They need to show future generations what they accomplished, and it needs to remain perfectly right there.
Wow, that's saddening. Do you have any clue what they're doing with the signage? I know we keep ours in a storage room to preserve the zoo's collection history.