Tiger Poachers Fear The Bite

Now this is the proper way to have Nature work for you:
Crocodiles scare tiger poachers in India

This is a bit like building a moat for your nature preserve. Also, tigers are most vulnerable to attack by poachers when they come to a water source for drinking or swimming, so the poachers will have to work harder and out in the open. Hopefully, the guards can make more arrests, as long as they don't keep succumbing to bribery.