So it doesn't detect poachers, it detects humans. And it requires drones flying non-stop over gigantic masses of land.
Edit: having dabbled in this field myself during my studies, I know from research that one of the biggest problems is simply corruption among rangers. It doesn't really matter if you can spot a poacher if a whole group of rangers will decide to not do anything about it (because for them the financial incentive of doing nothing can be HUGE). Of course the corruption problem stems from very low incomes and poor living conditions in those countries. If your monthly income is $100, it's quite tempting to accept a $10.000 bribe.
Edit: having dabbled in this field myself during my studies, I know from research that one of the biggest problems is simply corruption among rangers. It doesn't really matter if you can spot a poacher if a whole group of rangers will decide to not do anything about it (because for them the financial incentive of doing nothing can be HUGE). Of course the corruption problem stems from very low incomes and poor living conditions in those countries. If your monthly income is $100, it's quite tempting to accept a $10.000 bribe.
Edit 2: I worked on this: https://www.hackthepoacher.com/. We tried it with cell phone detection.