In many species taking out the biggest males actually increases the overall numbers.
One instance is red deer, where biggest stags tend to gather harems with more does that they can get pregnant. Killing these stags allows younger (and more fertile) stags to fertilize these does.
Another example is the brown bear. Bears are cannibalous, and the bigger the bear is, the more cubs and young bears it can kill. Kamchatka and many other parts of the world saw dramatic increase in bear numbers after start of trophy hunting.
