Ways as easy as sending a bunch of guys with rifles into the jungle?
You could legalize eating tiger. This will prevent tiger extinction in the same way it prevented cow extinction, result in sending some guys with rifles into the jungle that you don't even pay for, and if that's not enough, you can still send guys with rifles to finish off the wild population, and they still will be less likely to go extinct than if you do nothing.
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.