Kasos and the 14 smaller islands and islets around it – the so-called Kasonisia, along with the sea surrounding them – is an area that reaches 15,700 hectares included in the Natura 2000 Network thanks to the great variety of natural habitats. Kasos (as well as Saria of Karpathos) is one of the Important Bird Areas of Europe (IBA), because it is the place where rare birds of prey meet and it constitutes the first station of the migratory birds coming from Africa.
The types of natural habitats of Kasos are the following: Posidonia, Lagoons, Avathis, gulfs and small gulfs, sheer rocky coasts with vegetation in the Mediterranean Sea (with the native species Limonium spp.), annual vegetation with Salicornia and other species flourishing in the muddy and sandy zones, Mediterranean and thermo-Atlanitc halophilous scrubs (Arthrocnemetalia fruticosae), Mediterranean salt steppes (Limonietalia), Mediterranean gypsum vegetation (Gypsophiletalia), coastline mobile dunes with Ammophila arenaria (white dunes), Mediterranean Temporary Ponds, Rivers of the Mediterranean with seasonal flow, high bushy areas with Juniperus phoenicea, sparse degraded garrigues, Sarcopoterium spinosum, screes of the Balkan Peninsula, limestone pavements of the Aegean, primary grasslands in rocky roads, Caves.