I think the word "mass" indicates something over 50% of species. Not by definition, but as a personal gut feeling. We humans change the world and thus the environment of nature. However nature is resilient as hell. If I am correct humankind took shape during a bottleneck.

Now I love nature and animals. I am really curious about developing better communication with highly intelligent animals like birds, dolphins and dogs. But I hate the term fragile ecologic systems. Nature will crush us someday for sure. We should focus on creating an environment we, as humans, can live in. Nature will be just fine, she survived for billions of years.