Everything we call 'natural' has existed for generations and if it has not flourished it has at least maintained a steady state. In other words it has demonstrated Darwinian fitness. As environment change, though, the requirements for fitness change and some things that were once fit become unfit though no fault of their own. Similar to how all unfit things are unfit through no fault of their own.
Now consider that the environment is changing because of human activity. And by extension some things, animals and entire species, are becoming unfit because of us. But also some are becoming fit because of us. This, I would say, is that balance of nature.
While subsidizing a few species to give them a few more generations to try to adapt may give them more of a chance it seems kind of foolish to me to consider this preservation of nature. I want to describe this a preservation of a moment of nature. It even sounds absurd to me to try to preserve nature, as nature is the constant that chooses what is preserved.
While I may find opportunities in environmentalism I doubt I will make opportunites unless I can resolve issues like this with the movement.