As a Pleistocene refuge, the Sierra was a propitious habitat for thousands of species, many of which evolved in isolation within the Sierra and hence account for the rich biodiversity and high level of endemism, especially over 1000 meters (3280 feet). Therefore, the Sierra is one of the areas with the highest degree of endemism in the world. There are at least 600 botanical genera and over 3000 species of superior plants. It is know that 25 of the 514 species of birds registered for the Sierra are endemic (23 of them can be found within the reserve). Among the 46 species of amphibians and reptiles, there are 12 which are endemic. Finally from 120 species of mammals, one has been reported to be endemic.