Religion And Science Are Complements
There are two ways in which religion can conflict with science. The first is substantive: religion proposes factual theories that are incompatible with those of science. The best current example of this, of course, is creationism versus evolution. Literalist Christianity contains certain factual propositions, such as "the world was created in six days," which conflict with science's factual propositions. The other way science and religion can conflict is epistomological: religion asserts a moral injunction against the pursuit of certain knowledge by science, either because that knowledge is intrinsically something that we are not meant to know, or because the only feasible methodology for acquiring that knowledge would be unethical. Stem cell research is an example of the latter sort of conflict.
While I can't speak for all religions, neither of these sorts of conflicts are present in the case of Christian environmentalism. There is no substantive conflict, because the Bible does not contain any ecological theories. God may have told the Israelites where all the animals and plants come from, but he never pronounced on food webs and successional patterns. Christianity also does not offer any epistemological opposition -- nowhere in the laws of Moses or the teachings of Jesus are we told "thou shalt not conduct a biodiversity survey or build for thyself a computer model."
In the case of environmentalism, what religion provides is a value system. Science alone cannot tell us what to do. Science may find that expanding palm oil plantations cause declining biodiversity, but it takes the addition of an extra-scientific value premise -- "we ought to preserve biodiversity" -- to give us an agenda for action. Religion is, of course, not the only source of values, and one may reject religious environmentalism due to disagreements with the basis or content of that value system. But science is useless without some extra-scientific value system. To eschew Christian environmentalism in favor of science-based environmentalism is like saying that instead of getting a car with automatic transmission, you're going to get one with wheels. Regardless of how much you enjoy driving stick, it doesn't change the fact that automatic cars need -- and are perfectly capable of having -- wheels.