Thanks to its specific geographical position on the dividing line between several biogeographical regions and for its characteristic ecological, climatic and geomorphologic conditions, Croatia is one of the richest European countries in terms of biodiversity. The great diversity of land, marine and underground habitats has resulted in a wealth of species and subspecies, including a significant number of endemics.
One of the reasons for the large number of endemics in Croatia, and especially tertiary relics, is the fact that this area was not greatly affected by glaciation. The main centres for endemism of flora are the Velebit and Biokovo Mountains while endemic fauna is most represented in underground habitats (cave invertebrates, the Olm), the islands (lizards, snails) and the karst rivers of the Adriatic drainage basin (minnows and gobies).
Croatia contains significant populations of many species that are threatened at the European level. The most significant threat to wild species is habitat loss and degradation. Even today, there is great pressure to convert natural habitats into building or intensive agricultural land.
Adriatic Sea, the treasure of life
Despite the fact that the Mediterranean Sea is among the most threatened in the world - exposed to great anthropogenic impacts, the increasing impacts of climate changes and the resulting tropicalisation - it is certain that the Adriatic Sea is one of its best preserved gems. Although relatively small, the Adriatic Sea is one of richest seas considering the number of species and subspecies. Its Eastern part stands out for the great wealth and diversity of marine habitats, some of which are unique to this area, such as the submerged karst habitats that resulted from the rising sea level following the last glaciation.
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 has been recorded in the Croatian part of Adriatic Sea, of which more than 5,500 invertebrates. There are 442 recorded species of fish (it is about 62% of known species and subspecies of fish in the Mediterranean Sea (719)). Nine species of the infra order Cetacea (whales, dolphins) are occasionally appearing in the Croatian territorial waters and bottlenose dolphin (Tursiops truncatus) is the only resident species in the Adriatic. Another marine mammal species was recorded in the Adriatic Sea – the Mediterranean Monk Seal (Monachus monachus). There are three species of marine turtles (of the seven species in the world). The Loggerhead Sea Turtle (Caretta caretta) is the only resident species of sea turtles in the Adriatic.
There are about 600 species of algae in the Croatian Adriatic which build living communities in shallow coastal waters. Also, there are three species of seagrasses in the Adriatic, among which the Neptune Grass (Posidonia oceanica) which builds large marine meadows. Posidonia meadows are "factories" of oxygen and provide home and shelter to a great number of other marine species. They are the most important ecosystem in the Mediterranean as well as in the Adriatic. Nonetheless, seagrass meadows are quite endangered and have been slowly disappearing. Irresponsible fishing of marine species, habitat degradation caused by uncontrolled construction in coastal areas, marine pollution, unnecessary disturbance of marine species and invasive alien species are some of the major threats to biodiversity in the Adriatic whose conservation represents one of the greatest challenges.
One of the specific examples of marine species conservation efforts in Croatia is National Marine Animal Stranding Network. It was established five years ago and led by the State Institute for Nature Protection. At present, this network gathers around 20 different associates and successfully helps, rescues and monitors stranded endangered marine animals (marine mammals, turtles and cartilaginous fishes) and contributes to their overall protection.