"Naturalism," as far as I understand it, simply means taking one idea and making a fetish of it. (In this case, the idea of "nature.") As R.G. Collingwood put it, you can tell materialism is a religion because if you just substitute "God" for "nature" in a talk by a materialist, you'd have a perfectly good Christian sermon.
But I've never even found a consistent naturalist. A friend of mine at LSE told me, "I try to practice a naturalistic attitude towards sex." What he meant was that he wanted to sleep with lots of women. What he didn't want was the natural consequence of that activity, getting lots of women pregnant. That sort of naturalism he worked studiously to avoid, but whatever artificial means were efficacious.
Similarly, I've been reading The Beauty of the Beastly, a very entertaining book by Natalie Angier. She pitches a similarly "naturalistic" attitude towards sex. But she certainly doesn't take the same angle on dealing with other species. "Naturalistically" speaking, we should just wipe out any species that annoys us, the same way that lions wantonly kill cheetah cubs. That sort of naturalism must be firmly supressed.