Flora and Fauna of the Danube Delta

Flora

Delta vegetation is represented mainly by a specific vegetation wetlands (reed, bulrush, sedge, mixed with dwarf willow) and covers 78% of the total. Riverside coppices occupies 6% of the delta, are forests of willow, ash, alder, poplar, which grow on river levees, are regularly flooded and the stitches are covered by water and floating aquatic vegetation, occupying 2% of the delta. There is also the forests and fields Letea Caraorman and consist of gray oak, English oak, ash, poplar, elm, climbing plants.

Recent research has led to the identification of 955 species of wild cormophytes, including:
Eurasian elements (28%)
Eastern (24%)
European (14%)
cosmopolitan and adventive.
From an environmental perspective only a quarter of species (26%) are related to the aquatic environment (hydrophilic, hydrophilic and higromezofile), the rest being mesophilic, xerophyte, eurifile, halophile, psamofile. Note dominant give reed, bulrush, willows, floating plants (water lilies, cornacii, sickle). Find refuge in its delta some rare species, such as Ephedra distachya, Carex colchica, Nymphaea candida, Convolvulus persicus.

Fauna

Contains more than 320 species of birds as well as 45 freshwater fish species in its numerous lakes and backwaters. This is where millions of birds from different corners of the Earth (Europe, Asia, Africa, Mediterranean) come to roost. Major species of fish in the Danube Delta are pike and sleep.

Delta is a paradise fauna. Here lives  98% of European aquatic fauna, the whole fauna of Sighisoara, the lepidopteran aquatic mollusks and gastropods from Europe and here its rare mammals found refuge as lutreola Mustela, Lutra lutra and Felis silvestris. Vertebrates which, by their presence, give notice specifying the delta fauna. Amphibians are represented by two strange species and six species of anuria, with 8 species and reptiles, mostly snakes (4 species).
Fish are present in 65 species, mostly freshwater (60%), the rest of spring migrating from the Black Sea. Among the latter, sturgeon and mackerel are important, both scientifically and economically.
Birds are the ones that have created the fame of the Delta, known since the beginning of the century as an avian paradise. Fame is due to the 327 species that can be met in the delta that represents 81% of the fauna of Romania. Of these 218 species nest, the remaining 109 species passing through the delta and different periods of time remaining in autumn, winter and spring.

Aquatic birds are the most numerous: 81 nesting species and 60 species pass through the delta, a total of 141 species, representing 82% of European aquatic fauna. Aquatic fauna of the Danube Delta consists of a core of old species are well adapted to the aquatic environment, plus, accessories species and cosmopolitan species. Core avifauna is composed of 75 species whose life is related to the presence of water. They are grouped in five main ecological types: species closely related to water, strictly stenotope (dip, mirabelle, furtunari, pelicans, cormorants, spoonbills), species of reeds (all species of aquatic paseriforme) shore species (herons, fallow herons, spoonbills), hydrophilic vegetation species rich meadows with reeds (ralide), species of marine shores (some laride).

Many species, especially of ducks, geese, gulls, frequently occur in different biotopes. Accessory species are those that integrate secondary aquatic fauna, becoming increasingly turning as many aquatic ecosystems. Meadows are inhabited by Silvia, Flycatcher, filomele, Pitigoi, finches, plus, during the nesting ducks, cormorants and herons. In Letea forests and 64 species nest Caraorman nemoral typical forest avifauna (Silvia, blackbirds, woodpeckers, macaleandru, Pitigoi, starling, and tailed (Haliaetus albicilla), Milvus, dwarf eagle, osprey, etc.. Pheasant (Phasianus colchicus) was introduced through colonization rapidly developing population. In sandy steppe meadows are specific partridge, quail, cicârliile, Stone Curlew (Burchinus oedicnemus). The delta villages, in addition to households, are common Collared Dove, House Sparrow, Swallow , stork, swallow.

In the Danube Delta are several types of colonies: herons, spoonbill, herons and cormorants, pelicans and cormorants, gulls, and the avoazete ciocântorsi, the Black Tern, the terns. Pelican colony strictly protected area-Buhaiova Rosca is the largest in Europe and is an example of a mixed colony *. This is associated with several thousand pairs of white pelicans, with tens to hundreds of pairs of Dalmatian pelican and cormorant sea in a landscape reminiscent of Jurassic Park. Access is allowed only near the colony specialists who have obtained special permits from ARBDD of Tulcea.

Danube Delta climate

Danube Delta area falls within the semiarid temperate steppe Pontic specific. Flat water and very large spaces, covered in varying degrees of vegetation, interrupted by fields of marine sandy islands, forming an active area of ​​the Delta area and the adjacent lagoons, quite different from the Pontic steppe.

This active area responds to the total radiation received and the general circulation of the atmosphere resulting in a mosaic of microclimates. Total radiation varies between a minimum of 3.5 Kcal / cmp recorded in the winter months and a maximum of 17 Kcl. / cmp, in July. Depending on the intensity of activity centers to install the main barrel specific weather conditions: mild winter days (when the active center of north-eastern European barrel), cold winter days with strong winds (when acting anticiclonii North Atlantic), summer days hot and dry (when acting anticiclonii tropical Atlantic), rainy summer days (when the Mediterranean air interacts with the cold north-west Europe).

Duration of sunshine is high, the annual average is 2250 hours, but can reach 2600 hours in low nebulosity years. The temperature is distributed unevenly on the surface of the delta. Multi-media show the temperature increase from west to east. At the tip of the Delta (Tulcea) annual average temperature is 10.94 C in the river delta (Gorgova) of 10.96 C, on the seashore (Sulina) of 11.05 C and the Black Sea (Platform Gloria) of 11.86 C.

Average daily high amplitudes reflect differences due to the nature of active surface: the Gorgova varies between a maximum of 9 C (July) and a minimum of 3.8 C (December), from Sulina between 2.8 C (July) and a , 4 C (in November), and Gloria station between 2.3 C (July) and one C (in December and February). The annual average daily temperature viscosity of the actual close of 1600 C. The air humidity recorded the highest rates in Romania. Relative air humidity in winter varies between 88 - 84% to 85% and 89 Gorgova Sulina and St. George, and in summer, between 69-71% at Gorgova and 77-80% at Sulina and Saint Gheorghe. Rainfall is low and quantity decrease from west to east due to the effect of specific surface active delta and the Black Sea. On entering the Danube Delta (Tulcea) recorded an average yearly rainfall of 450 mm, and at Sulina, 360 mm. For the most part of the Delta fall between 350 and 400 mm rain, and the delta coast and most of the lagoons, less than 350 mm.

Snow layer is thin and short periods of time, only more severe winters. Such situations have occurred in the years 1928-1929, 1953-1954, 1941-1942, 1984-1985, when the sea shore near froze for 45-60 days. The dominant winds blow from the northern sector alternative to the southern sector, the most intense wind acceleration occurring in winter and transitional seasons. Seasons are very unevenly distributed in the Delta area. On entering the delta, Tulcea, averages 90 years reveals that there are 142 days of summer and 60 winter days and took nearly egaăa springs with autumns. At the same average annual Sulina show 145 days of summer and winter only 15 days, and springs are longer (122 days) than the autumns (83 days).

Danube Delta Geomorphology

Danube Delta, located in the NW Black Sea (between 44 ˚ 46'00 "wide. N - Bugeac platform, 45 ˚ 40'00" wide. N and 28 ˚ 40'24 "long. E - North Dobrogea orogen, and 29 ˚ 40'50 "long.'s - the Black Sea platform), representing a relief Geomorphologically accumulation developed at the mouth of the Danube in the Black Sea. (Coteţ P., 1973, Gh Romanescu, 1995)
According to FAO classification (SOTER - Procedure Manual, 1993) [5], the Danube Delta is included under regional landforms type wet lowland river on alluvial deposits with a high degree of fragmentation.


Delta is characterized by positive landforms called levees and negative landforms represented by depressions filled with water (lakes). Currently, Delta is in the form of a flat with a slope of 0.006 ‰, crossed by a web of water: the river arms, channels and streams, punctuated by lakes and backwaters. Differences in elevation above sea level, are 8-10 m in the levees and -2 to -4 m in the lake depressions.

Danube Delta territory is divided into two geographical subregions, namely: Delta itself occupying an area of 4250 km2, located between the river arms and Razim area, with an area of  990 km2. The physico-geographical Delta arms across the river is divided into two natural sub-delta and delta river sea.

River Delta covers over 65% of the total area of the delta and extends to Ceatalul Ismail, to downstream until Letea and Caraorman Periprava line (on Chilia) - Crisan (Sulina arm) - Ivancea (Holy arm . George) - Crasnicol - patties. The Danube Delta is sub-divided into several natural units such as: Depression Sireasa, sont-Storm Depression Depression Pardina Depression-Merhei Matiţa, Grindul Chilia Grindul Stipoc in evolutionary Tataru in evolutionary Babina in evolutionary Cernovca Depression Litcov, Erenciuc Depression, Depression-Buhaiova Rosca, Tulcea Meadow Dranov-Dunavăţ Murighiol and Depression, etc..

Delta Ocean less than 35% of the Danube Delta area, east of the line-Crisan-Ivancea Periprava-Crasnicol-perishable. In this sub-region, as in the river delta, we find areas with positive and negative relief, but unlike the first subregion, the bottom of the depression is below sea level in most cases.

Geology of the Danube Delta

The Danube Delta is located, in geological terms, in a region of crust mobile platform called Delta (region predobrogeană). Delta platform comes into contact with the south-western North Dobrogea orogen by Oancea fault-St. George, which is roughly parallel to the St. George arm.

Its geological structure is composed of a crystalline foundation over which has a transgressive sedimentary sequence represented by deposits Paleozoic, Triassic, Jurassic, Cretaceous, Neogene and Quaternary, induced by large and shallow drilling conducted in the area. Deposits of Paleozoic age, the floors are Silurian-Permian (438-230 million years ago), consist of limestone, dolomite, silt, lithic sandstones, with intercalations of tuffs vitroclastice.

Triassic deposits (248-213 million years) are formed at the base of ferruginous silt, clay, sandstone, microconglomerates with intercalations feldspathic Gates, diabase and melafire and transgressive occurring dolomite, sandstone, limestone, silt, marl AND . a. containing plant species (Striatoabietites sp. Ovalipollis Oval etc.), foraminifers (Glomospirella sp. Spirillina sp. etc.), conodonde (Gondolella navicula, Gladiogondolella tethydis etc.).

Deposits of Jurassic age (ages Dogger-Malm - 176-142 million years) are mainly composed of limestone (the base), clay, limestone, sandstone, limestone and gray and yellow (on top), with fossil foraminifers ( Textularia Jurassic, Spirillina orbicula etc.) dinofagelate (Nannoceceratopsis spicula, N. pellucida, Ctenidodinium panneum etc.), etc.. Cretaceous deposits belonging floors Apţian-Senonian (121-65 million years) are composed mainly of ferruginous clay and silt with intercalations of fine sandstones and dolomites gipsifere, containing a poor phytocoenosis Trilobosporilites apiverucatus, triplex Clavifera etc..

Neogene age deposits (Sarmatian-Romanian floors - from 13.5 to 1.8 million years) are composed of a succession of layers with lumaşelice limestone, sand, silt and clay, with Mactra sp., Sand, silt and clay reddish with Dosinia maeotica, fine gray sand (with Dreissena rimestiensis, Limnocardium sp. Stylodacna orientalis sands and sands with clay intercalations, containing specimens bifarcinatus viviparus, etc. Dreissena polymorpha.

Quaternary age deposits (deltaic deposits belonging to the Pleistocene-Holocene floors - 1.8 to 0.01 million years) are formed at the base, a brick-red clay layer followed by a succession of layers of gravel, sand , silt, clay and loess, and silt at the top is available for fluvial and fluvial-lacustrine origin.

Danube Delta

Danube Delta (3446 km ²), located largely in Dobrogea, Romania, and partly in Ukraine, is the largest and best preserved of European deltas.

Delta entered into the UNESCO World Heritage in 1991, is classified as a national biosphere reserve in Romania as a national park in the IUCN international taxonomy.

 The Danube delta is bounded on the south-west of Dobrogea Plateau, north forms the border with Ukraine, and flows east into the Black Sea. The Danube Delta is crossed by parallel 45 ° N and longitude 29 ° longitude E. Delta deal with Razim - Sinoe 5050 km ², of which 732 km ² are in Ukraine, Delta Romanian being awarded to an area of 2540 km ². Due to the 67 million tons of silt to the Danube Delta is increasing annually by approx. 40 meters.

The Danube has reached the Patlageanca bifurcates into two arms, Chilia north and south of Tulcea arm, arm then fog-Saint George, breaks arm in arm Sulina and Saint Gheorghe.

Chilia, forms the border with Ukraine, and his course of carrying on a length of 104 km ², 60% of the Danube waters and alluvium.

Sulina arm is located in the heart of the Delta, and unlike Chile, has a straight course, always maintained dredged for navigation and maritime vessels. It has a length of 71 km and carries 18% of the Danube water.

Course arm of St. George is facing southeast, and conducted on 112 km, carrying 22% of the flow of the Danube. The islands form the estuary delta Sacalin considered a top secondary.

Delta (except delta secondary Chilia) is traditionally part of Dobrogea, but in Antiquity and Middle Ages, the coast is much more to the west (between Chile and Murighiol Old Strabo's time, between Lake and Periprava Dranov the Byzantine era ), so that historical maps are including all Delta Dobrogea current geomorphological are false.