Because the biological system on this planet is a closed system (no life seeping in from outer space that we know of) and because life forms are limited and made up of limited elements, we can logically assume interdependency of life forms. Yet, generally we humans see that relationship abstractly, at a distance, so we take the extinction of species as something that might concern scientists and ecologists, something sad and maybe inevitable, but not as something we can affect.
This new study of the little brown myotis bat die-back showing a correlation to infant death seems a major demonstration of our pretty direct relationship to other species. While statistical correlation is not a causal mechanism, the correlation demonstrates the existence of an as yet unknown causal chain.
To read the article click on this link: https://www.commondreams.org/news/bats-infant-mortality.
In 1962 Rachel Carlson wrote The Silent Spring. It chronicled her observations of the deleterious effect of pesticides all along the food chain during her 17 years working for the Department of Fish and Wildlife. She is considered one of the parents of the environmental movement and her work was instrumental in many of the controls placed on the use of pesticides today.