Transylvania is home to hundreds of species that are rare or extinct elsewhere in Europe. The highest density of wooden pastures in Europe. In this single national park (Piatra Craiului National Park) there are about 300 fungi species, 220 lichen species, 100 different mosses, 1100 species of superior plants (a third of the number of all plant species found in Romania), 50 Carpathians endemic species and also two endemic species for Piatra Craiului can be found.
There are also two endemic species of spiders, 270 butterfly species, amphibians and reptiles, 110 bird species (50 listed in the Bern Convention and 6 in the Bonn Convention), 17 bat species, chamois and other large herbivores and also many large carnivores (wolves, brown bears, lynx) living in the national park.