The most famous biogeographical region present in the country is certainly the Mediterranean, located along the Eastern coast of the crystal-clear Adriatic Sea. The exact number of species and subspecies that really live or breed in the Adriatic is still not known. According to a very rough estimation, between six and seven thousand species of flora and fauna may live in the Croatian part of Adriatic Sea, of which more than 5,500 invertebrates. This region, with mild Mediterranean climate and karst, has an exceptionally large number of endemic plant and animal species.
The Alpine region in Croatia still retains the look of wild and untouched nature and comprises the Dinaric mountains with the karst cave systems, mountain pastures, dense forests where bears, lynx and wolves roam freely, and karst fields with rivers.
Central Croatia, which is part of the Continental biogeographical region, is characterized by gentle hills covered with forests, which increasingly lower to the East leading into the Pannonian plain.
The number of known species in the whole of Croatia is around 38,000, though the estimated number is far higher – from 50,000 to over 100,000. This is a very significant number for a relatively small country. Although Croatian nature is of high value, many of its species are threatened according to the IUCN criteria.