Are there any way that the zoo may decrease the biodiversity?

Well, in African lots of hunters kill porcupines for their quills which decreases their biodiversity. Which then they're will be less porcupines at the zoo. But if the Zoo doesn't want them to reproduce they can put them in different rooms, they can also let them out in the wild agin that way they might get shot by a hunter or killed by a predator. That way the biodiversity of the animal will decrease.