What on Earth is "Environmental Conservation"? I know conservation of energy and momentum and angular momentum (no one of which contradicts evolution), but conservation of environment? It doesn't happen. See all the current stories about loss of habitat, or think what the Chixalub comet did to the environments of the time.
OK, then I understand. The environment of evolving creatures can always vary from all sorts of causes, ice ages, droughts, comets, etc. Humans are only another variety of change. Animals and plants will evolve according to whatever is out there, whether it is suburbs rolling over habitats or dogooders preserving some patch of forest. It takes a number of generations for evolution to show up but show up it will in the fullness of time.
If the world was to change e.g. via gloabal warming, and certain insects are not be able to live ... then should we preserve them? Wouldn't it betta to let them fight it out so that the fittest amongst them survive?
There is no better or worse in evolution, only outcomes. Human beings and human societies have moral preferences, but from the point of view of evolution these are no more moral than a comet strike. Que sera sera.
One way to look at it is that humans are just another factor in natural selection. Our challange, being an imperfect & volitional factor of natural selection, will be to keep the ecosystem working for us instead of against us...whether that is aesthetics or life and death. Obviously, our mucking about is bringing down a large number of species, but that is not the first time in the history of the world a massive die-off has happened. (Not that I don't care...I do care because I believe it to be immoral and because, in a practical/selfish sense, it weakens the ecoystem we rely on for a happy life.) Anyway, the evolutionary history that is unfolding is certainly different than it would be if we weren't here.
The thing with saving endangered species is that we know the current ecosystem is beneficial to us...so it makes sense to preserve it.