One cannot fully support both Darwinism and Conservationism simultaneously.
That really sounds quite controversial at first when you read it, but if you take a step back for a moment, maybe you'll see what I am getting at...
Darwinism, or for the sake of making my point a little better to read, Natural Selection, thrives on the idea of "survival of the fittest." If Rat A and Rat B both are subjected to the same environment and contract the same disease, and Rat A survives while Rat B dies, then according to Natural Selection, the gene pool has been strengthened by the rat with the stronger genes (Rat A) surviving, and the weaker genes (Rat B) dying off, eventually producing a species of rat immune to the disease. So effectually, Darwinism promotes the strong surviving whilst the weak dies off, creating a healthier gene pool.
Conversely, Conservationism thrives on the idea of preserving life. A true conservationist will administer medicine to Rat B to conserve life. A better illustration would be an endangered species; suppose a beaver dam is built and changes an ecosystem. Creatures dependant on the river will have to make some changes, and in the event that they can't adapt to the newly created pond, they will likely die. In history, Darwinists believe that this caused some species to die out, while other species survived and came out stronger for it. Herein lies the problem: As a species is beginning to die out, making way for the stronger species, the true conservationist is obliged to intervene and save the weaker species from extinction, using the loss of the species as a worse outcome than the emergence of a stronger species.
I am getting a little long-winded, I know, so the above can be summed up in one simple phrase:
Darwinists (Natural Selection) rely on the weaker species dying off.
Conservationists (Environmentalists) rely on saving the weaker species.
The two are complete polar opposites!
It is for this reason that I scoff at environmentalists who are such huge proponents of Darwinism-- the very ideals they believe in totally contradict their perfect picture of life.