That implies that less ivory makes it to the market which means that more elephants make it through life without getting killed for their tusks.
Ivory isn't as easily produced as most drugs so the price of ivory is dictated by scarcity even absent any other controls.
You could make as much of most drugs as bulk chemistry or farming allows.
So the value of ivory going up as a result of being tougher on poachers would be proof that it is working.