Biological diversity or biodiversity refers to the entire spectrum of different life forms: microorganisms, plants, animals, as well as the genes that they contain and the ecosystems that they form.
Flora and fauna
In the protected area of the Axios Delta, rivers, lagoons, salt marshes, fertile fields and the sea give shelter to hundreds of species of plants and animals. More than 370 species of plants exist in total. Some are protected, like the sea daffodil, the water fern and the water chestnut, while others are very popular across numerous points in the protected area, but still contribute greatly to the conservation of the character-structure and functionality of the coastal water ecosystems:
- glassworts which adorn the coastal salt marshes with their autumnal red colour and create small ‘islands’ within the flooded grounds, becoming home to black-winged stilts and shelducks
- the dense clusters of reeds and rushes which hide the nests of purple herons, the hatchlings of the mallard and the listless lake frogs who capture insects with their flexible tongue.
The proximity of the protected area to the urban fabric and the pressure it undergoes from intense man-induced activities such as agriculture, stockbreeding, sand extractions and mechanization have had severe repercussions on numerous vegetation types, such as:
- the valuable riparian forest with its willows, alders, poplars, elms and black-elms which contains the riverbanks and creates the necessary natural paths for the safe passage of wildcats and wolves, while the seldom otter rests and nests at the roots of the trees
- the windswept dunes with sea lavender, purslanes, pimpernels and sea weeds which offer refuge and food to butterflies, beetles, as well as the Mediterranean and Greek turtle.
The protected area of the Axios Delta is a valuable biotope for many animal species, some of which are endangered, like the European ground squirrel and the otter, and some of which are elusive, as they move either inside the vegetation –wildcats, snakes, turtles – or they move around silently at night –bats. Others, like wolves, are active in groups mostly around dusk, while the presence of other animals is more common, though are not always visible (foxes, badgers, shrews, marmots). The relevant bibliography and the corresponding field work have documented in total 50 species of mammals, 27 species of amphibians and snakes, more than 50 species of fish living in inland waters and in the sea and 65 species of invertebrates – mostly insects. It is worth noting that one of the largest populations of Mediterranean turtles in Europe has been observed at the dunes of Alyki Kitrous.
This region is of worldwide ornithological importance, as considerable populations of rare birds stop, nest or overwinter here. These species include the Dalmatian pelican, the avocet, the black-tailed godwit, the night heron, the squacco, the collared pratincole, the Mediterranean gull and the pygmy cormorant, the oystercatcher and the Kentish Plover. Given its location on one of the main migratory routes in Europe, thousands of water birds stop in this wetland during the migration season in order to feed, while important numbers of waterbirds at a European level gather here during the winter.
A total of 299 species of birds have been documented in this area – that is, 66% of all bird species observed to present in Greece, and of these 106 nest here.