Absolutely agree with German here. "letting nature take its course" is an easy out for those people (unlike most of us on this forum) who don't understand that our species has already meddled with most of the planetary ecosystems. The best ideas usually come from field experience/data, evaluated with some understanding of how an ecosystem works.
As for "natural": cholera is natural, so is death in childbirth and a limited human lifespan. We are the ultimate, meddlesome primate species, constantly invoking the law of unintended consequences!
"Trust in God; all others bring data"
Funny how you say letting nature take it's course is not good, but then slam humans for meddling with ecosystems. Such as controlled burns and mechanical thinning of the forest?