A place with many deer and wolves is likely to be a good environment for wolves and a bad environment for deer. You must ask either the deer or the wolves and both will give true but conflicting answers. A place made by humans into a good environment for humans may turn out to be a bad environment for wolves. The interests of species are often in conflict. The thought that there is some delicate harmonious state in which each strand in the web of nature is held taut in perfect shimmering balance is a fantasy.
Biologists sometimes say that to a first approximation, all species are extinct.
Which is to say that Earth throughout history has been a very bad environment for all but a tiny fraction of species. Without a single person or power plant, Earth's ecosystem has managed to extinguish almost every species that it has ever produced. Whatever balance exists is a constantly shifting, dynamic thing. Change is the rule. And some of these changes produce fatal environments for some species and happy environments for others.