One of the reasons why the Danube Delta has become a biosphere reservation is because, in comparison with the other deltas of Europe and even the rest of the world, it has preserved a higher level of biodiversity, whereby we understand a large number of species from a large diversity of systematic units. Furthermore, the Danube Delta is striking for the high density of many of its species, which are rare or lacking in other regions of the continent, in spite of the fact that, due to the effects of human activity in recent decades, the numbers and habitats of these species have also been gravely affected. Since 1991, the flora and fauna of the Danube Delta Biosphere Reserve has been undergoing an inventory, with two major objectives: to gain knowledge of a major component of the natural heritage within a biosphere reservation and to highlight the species that require protection and conservation measures. The mosaic of habitats that have developed in the Danube Delta Biosphere Reserve is the most various in Romania, hosting a great variety of plants and animals, whose numbers have been estimated at 5,380 types. · 30 types of ecosystem · 5 380 species, of which · 1 839 species of flora · 3 541 species of fauna · Molluscs (91 species) · Insects (2 244 species) · Fish (133 species) · Amphibians (10 species) · Reptiles (11 species) · Birds (331 species) · Mammals (42 species) A NATURAL GENE BANK OF INESTIMABLE VALUE TO WORLD NATURAL HERITAGEFLORA - 1 839 species The flora of the Danube Delta Biosphere Reserve is represented by more than 1,839 taxa, and around seventy per cent of the Delta's vegetation is dominated by reeds (Phragmites australis), lesser bulrush, or narrow leaf cattail (Typha angustifolia), combining with Scirpetum and reed vegetation to form floating islets. In the lakes and channels can be found aquatic plants represented by underwater species: lily (Nymphea sp., Nuphar), water chestnut (Trapa natans), Potamogeton sp., Myriophyllum sp., Utricularia sp. The willow woods lie on the higher banks (Salix trianda, Salix fragilis and Salix alba), while the smaller grey willow (Salix cinerea) grows on lower banks. In the forests of Letea and Caraorman, which have developed in the damp, low-lying areas between the sandbanks, there grow species of oak (Quercus robur, Quercus pedunculiflora) together with species of ash (Fraxinus angustifolia, Fraxinus pallisiae), and various shrub and climbing plant species such as wild vine (Vitis silvestris) and liana (Periploca graeca). The sand dunes are characterised by the presence of arenaceaous plants (Koeleria pyramidata, Koeleria glauca, Festuca pallens etc.). In areas of saline earth there frequently grow halophile plants such as Salicornia herbacea, Suaeda maritima, Puccicinelia distans, Aeluropus littoralis, and Limonium gmelini. A distinct category is formed by rootless, floating plants such as Salvinia natans, three species of Lemna, and Wolffia arrhiza, Utricularia vulgaris, and Spirodela polyrrhiza. During the period in which an inventory of DDBR species was made, two species new to science were discovered: Centaurea pontica, and Elymus pycnattum deltaicus. FAUNA - 3541 speciesThanks to the favourable conditions created by the large variety of terrestrial and aquatic habitats, as well as the proximity of a number of sub-zones of the Palaearctic fauna region (e.g. Mediterranean, Pontic, Eurasian), the fauna of the DDBR is estimated at 3,541 species (3,061 invertebrates and 480 vertebrates). The invertebrates form by far the greater part of the DDBR fauna, with over 3,000 species. Of these, 435 are species of worm and rotifers, 91 species of molluscs, 115 species of crustaceans, 168 species of arachnids, and 2,244 species of insects. Up to now, thirty-seven species new to science have been described, including a worm, the Proleptobchus deltaicus, five species of arachnid, one fish species, the Knipowitschia cameliae, and thirty species of insect, including Isophya dobrogensis, Diaulinopsis deltaicus and Homoporus deltaicus. The fish of the DDBR are remarkably varied, comprising eighty-six species included in twenty-two families. The majority of these are freshwater species, but there are also marine and eurihaline species from the Black Sea, which penetrate the Danube Delta during the reproduction season. Approximately a third of the species are or have been exploited commercially, including the sturgeon group (a ten-year fishing ban was placed on this species in 2006) and the Pontic shad (Alosa pontica). Amphibian and reptiles species are well represented in the DDBR, with most species being protected by law. There are ten species of amphibian: fire-bellied toad (Bombina bombina), European tree frog (Hyla arborea), common spadefoot (Pelobates fuscus), common toad (Bufo bufo), green toad (Bufo viridis), Pelobates syriacus balcanicus, Rana lessone and two species of water lizard, Triturus dobrogicus and Triturus vulgaris. Reptiles are represented by eleven species, including lizards (Sauria) and snakes (Serpentia). However, the DDBR remains most renowned for its birdlife, with a total of 331 recorded species (excluding the 520 species recorded in the rest of Western Europe). The region is of universal importance as a nesting area for a number of bird species such as the white pelican (Pelecanus onocratalus), Dalmatian pelican (Pelecanus crispus) and pygmy cormorant (Phalcrocorax pygmeus). There are also major colonies of common spoonbill (Platalea leucorodia) and a number of nesting species of white-tailed eagle (Haliaeetus albicilla). The Danube Delta is a major resting place, both in summer and in autumn, for millions of birds, particularly duck, white stork (Ciconia ciconia) and numerous species of birds of prey. In the winter season, the DDBR is home to large groups of swans and geese, including almost the entire population of red-breasted goose (Branta ruficollis). The 331 bird species include:· The greater part of the European population of white pelicans (Pelecanus onocrotalus) and Dalmatian pelicans (Pelecanus crispus)· 60% of the world's population of and pygmy cormorant (Phalcrocorax pygmeus)· 50% of the world's population of red-breasted goose (Branta ruficollis) Mammals are represented by forty-two species including important European conservation species, such as the otter (Lutra lutra) and mink (Lutreola lutreola). The muskrat (Ondatra zibethicus) and wild boar (Sus scrofa) are economically important for fur and hunting respectively. Predators are represented by the stoat (Mustela erminea), enot dog (Nyctereutes procyonoides), fox (Vulpes vulpes) and wildcat (Felis silvestris). By the Berne convention, a large number of birds are protected species (320 from a total of 331 species), followed by 22 mammal species, of which seven are strictly protected. Likewise, 24 species of fish are protected, 22 strictly protected. ECOSYSTEMS IN THE DDBR In the DDBR, there are thirty types of ecosystem (twenty-three natural and seven man-made).Of the curiosities and superlatives that make the Danube Delta unique, the following are particularly worthy of note:¨ The best-conserved wetland in Europe¨ The newest land in Romania, still being formed today. The Chilia Arm has the strongest alluviation, at its mouth, continuing at a rapid rate the extension of the secondary delta¨ The oldest nature reserve in the Delta is the Letea Forest, declared a protected area in 1938¨ The most characteristic formation of the Delta are floating reed islets – a tangle of rhyzomes and plant roots, mixed with vegetal remains and alluvium, which, once, dislocated, becomes a floating mass¨ The most extensive area of compact reed beds in the world – approx. 175,000 hectares¨ Birdlife – 331 species of birds, of which 320 are protected by the Berne Convention¨ The largest colony of white pelicans (Pelecanus onocratalus) in Europe is in the entirely protected area of Roşca-Buhaiova¨ In the DDBR can be found 60% of the world's numbers of pygmy cormorant (Phalacrocorax pygmaeus) and 50% of the world's numbers of red-breasted geese (Branta ruficollis) during winter¨ The greatest curiosities of the Delta are the oak forests and lianas. The most interesting liana, with a length of up to 25 m, is the Periploca graeca, which is Mediterranean in origin and reaches its northernmost limit on the sandbanks of Letea and Caraorman¨ The largest oak tree – Quercus pedunculiflora – can be found in the Caraorman Forest, with an age of more than four hundred years and a circumference of more than 3.8 metres¨ The most venomous spider is the black widow – Lactrodectus trecimguttatus – found in the Letea area and on Popina island¨ The largest beluga (Huso huso) ever caught weighed 882 kg¨ The largest carp (Cyprinus carpio) ever caught weighed 46.5 kg.The smallest fish is a goby (Knipowitschia cameliae), whose length does not exceed 3.2 cm, and is found only in Portiţa.
by Danube Delta Biosphere Reserve
