What do humans do to protect the biodiversity of earth

I know one way is by the reduce use of pesticides. The less in a sense the better.

As a man, created out of nothing but pancakes, I can only assume a true human would have the answer but I will fill you in, regardless. I think humans protect the environment in a countless number of ways, but it is not this what counts. It is the fact that humans don't learn from their mistakes: they don't eat enough pancakes. That, my dear, is my take on your question.