Croatia can be subdivided between several ecoregions because of its climate and geomorphology. The country is consequently one of the richest in Europe in terms of biodiversity. There are four types of biogeographical regions in Croatia—the Mediterranean along the coast and in its immediate hinterland, Alpine in most of Lika and Gorski Kotar, Pannonian along Drava and Danube, and Continental in the remaining areas. The most significant are karst habitats which include submerged karst, such as Zrmanja and Krka canyons and tufa barriers, as well as underground habitats. The country contains three ecoregions: Dinaric Mountains mixed forests, Pannonian mixed forests, and Illyrian deciduous forests.