In Jurassic World Evolution how can I mix carnivores and herbivores without the herbivores basically being attacked the second they walk out of the gate? Or am I supposed to keep them in 2 separate areas and build a new research center? I would like to mix them it seems like more of a natural habitat but right now its more of a buffet for a few carnivores.
To have carnivores and herbivores in the same enclosure, you need to balance their attack, defense, and aggression. The herbivores need to be able to defend themselves from the carnivores but also neither side should be so aggressive that they'll fight to the death.
I've had fairly good success mixing Triceratops and Velociraptor in a large enclosure with different feeding stations on different sides of the enclosure (meat on one side and plants on the other). You might also have success with similar pairings of small carnivores like Dilophosaurus or Deinonychus with strong herbivores like Anchylosaurus or Stegosaurus.
Larger carnivores like the Carnotaurus or Allosaurus are simply too powerful and aggressive to live in an enclosure with other dinosaurs, let alone herbivores.