I doubt that the animals would be the slightest bit bothered by a roller coaster in that area. Chances are that you wouldn't even be able to hear it from the Oasis - steel coasters are typically pretty silent.
Tarzan Rocks, on the other hand, can clearly be heard in several of the animal habitats, with no visible effects.
Even if you were able to hear the coaster, I doubt that these animals would be significantly bothered by it, after seeing some 8 million noisy people pass by them each year.
Take Epcot for instance. Illuminations is definitely MUCH louder than a coaster, and they don't seem to be too bothered by it. The wild ones just gather around the side of the lagoon, and the captive ones don't really do anything.