I don't know.. sounds like semantics more than any real difference .. but I get what you mean. If we extract resources from the environment in such a way that the the environment in more or less preserved in it's original state, that's conservation/environmentalism
That said the government plays a role in conservation. If I'm in business, producing a pollutant as a by product, I'd have to dump my byproduct in the nearest stream, just like everyone else who makes a similar product, to stay competitive. But, if the government says , to me and all my competitors, no, no dumping allowed, it puts all at the same economic advantage, and preserves the common good: the clean stream
That's the reasoning from the view of the producer. From the innocent bystander just trying to fish the stream, or get a drink of water, it's protection of the common good