Scientific Tourism In The Danube Delta

Cultural tourism, with one of its most attractive variants – scientific tourism – has lately been gaining ground all over the world, being one the few forms of knowledge that unite relaxation and delight with a broadening of one's intellectual horizon.In its complexity and originality, the Danube Delta is a perfect tourist destination, as interesting as it is useful for discovering a complex biotope that offers both a unique landscape and a specific way of life, rarely met with on the continent or elsewhere in the world. The Danube Delta is the best-preserved biological environment of this type in the world. The 5000 hectares of the Delta are home to the largest known reed-covered surfaces and to the complete range of lacustrine plants; also to be found here is a rich and diverse fauna, especially ornithological and ichthyologic (over 150 species of birds and almost 100 species of fishes). THE FLORAThe reed's immense dominion would alone deserve special research, since it plays an important role in maintaining the natural balance of the delta, blocking alluvial deposits, lifting mineral salts from deeper strata to the surface, offering fish shelter, food and possibilities for reproduction, and also being a 'green goldmine' for the national economy. Beside this, the delta's rich vegetation reflects multiple living environments that define a range of vegetal groups and types well adapted to its successive layers. 1. Water Plants. This category includes vegetation with floating leaves (usually having roots anchored in the silt) and submersed or unrooted vegetation, floating freely with the current. The former encompasses plants that cover the surface of the water with leaves and flowers, such as: the white water-lily (Nymphaea alba), the yellow water-lily (Nuphar luteum), the yellow floating-heart (Lymnanthemum nymphoides), the water caltrop (Trapa natans), and floating-leaved pondweed (Potamogeton natans). The latter category includes plants that float through the mass of water, rarely being rooted – such as the water soldier (Stratiotes aloides), which damages fishing nets because of its rigid, truncated, spiky-edged leaves, the hornwort (Ceratophyllum), the water milfoil (Myriophyllum) – as well as natant plants at water surface: various species of duckweed (Lemna) and the frogbit (Hydrocharis morsus-ranae). 2. Bog and Waterside Plants. A wide range is included here. The most important type is represented by floating reed islets. Towards the inside, they are bordered by the club-rush (Schoenoplectus), they continue with a girdle of cattails (Typha) that advances towards the water and they end in a mass of carrizo (Phragmites). An interesting macrocosm of amphibious plants evolves inside these reed islets, plants which have water-adapted leaves during floods and land-adapted ones the rest of the year: the amphibious bistort (Polygonum or Persicaria amphibia), or the mare's tail (Hippuris vulgaris). This category also includes characteristic species of floating reed, such as fern (Dryopteris thelypteris), the marsh spurge (Euphorbia palustris), sedges (Carex), bur-reed (Sparganium), the dropwort (Oenanthe), the arrowhead (Sagittaria), the mad-dog weed (Alisma plantago), the flowering rush (Butomus umbellatus), the yellow flag iris (Iris pseudacorus), as well as two rare species that grow at the mouth of the branch Chilia: the common sweet flag (Acorus calamus) – an aromatic plant, and the bog arum (Calla palustris) – an ornamental plant related to the calla lilies sold by florists. Inside floating reed islets and in their vicinity, rich in organic substances, isles of mush thicket get formed which are similar to mole-hills. They are the result of various species of club-reed and sedge drying out, and are usually harmful for the reed islet, suffocating it. There are also sand islands in the Delta, which are called spits, and which display three layers of vegetation: an unstable layer of sand – covered with feeble dune vegetation; a somewhat wetter but more stable layer – where steppe meadows get formed which are dominated by the rosemary-leaved willow, the Ephedra Distachya, the spurge (Euphorbia), the Petasites paradoxus, the sea-buckthorn (Hippophae); and, finally, a layer of wooden vegetation, the so-called sand woods (Letea, Caraorman), unique in Romania and the world, and which would alone deserve special study. In the regions of the Delta where waters are poor in nitric substances, carnivorous plants appear. These plants compensate the lack of proteins by using a series of ingenious traps and thus capturing small organisms (cyclops, water fleas, infusoria). They secrete digestive juices just like the organisms' stomachs. Examples include the bladderwort (Utricularia) – having bladder-like traps, and the delicate Aldrovanda, having leaves modified to resemble small rounded capsules which close suddenly at the touch of any small organism. THE FAUNAFor tourists passionate about zoology, the Danube Delta will reveal itself as a place favorable to the growth of an immense number of animals adapted to the various biotopes and numerous local biocenoses. Even to this day, a complete faunal inventory has not been put together, economic interests having prevailed over the scientific ones since 1950. Broadly speaking, lower animals of the delta are those commonly found in permanent plain marshes and lakes: spongiae, hydras, worms, marsh clams, Pulmonata, crustaceans, marsh spiders, insects such as dragonflies, mosquitoes, and birds such as the great bittern. The existence, in the maritime delta, of a characteristic butterfly deserves special mention: the Rhypariorides metelkana, which was discovered by the Romanian entomologist A. Popescu-Gorj. Usually flying over the reed and floating reed islets, the butterfly has yellow-orange abdomen and thorax, lemon-yellow hindwings with black spots and rusty stripes and reddish forewings also with black spots and rusty stripes.Often to be found in the delta are reptiles, such as the fish-eating European pond terrapin (Emys orbicularis), the dice snake (Natrix tesselata), amphibians, especially the edible frog (Rana esculenta) and the marsh frog (Rana ridibunda), which are caught with special trawls and used for commercial purposes. The most important groups of animals in the delta, however, besides fishes, are birds and mammals. Thanks to its temperate climate, the natural shelters it offers and to an abundance of food, the Danube Delta is migratory birds' main halting or resting place between the arctic and tropical regions. Besides migratory birds, however, there is also a large number of rare species that nest in the Delta as summer guests, while others hatch in northern Europe and come to spend the winter in the Delta. Five of the most important migratory pathways go through the Delta, turning it, especially in spring and autumn, into a real ornithological paradise. Its deep recesses, the shorelines of creeks, marshes and backwaters, reed thickets and bushes are all teeming with a variety of birds, ranging from the European penduline tit and the mustached warbler to swans, pelicans, egrets and cranes. We will find, in the Delta, representatives of European and world ornithological fauna: the great white pelican (Pelecanus onocrotalus), the Dalmatian pelican (Pelecanus crispus), the common shelduck (Tadorna tadorna), the great egret (Egretta alba), the little egret (Egretta garzetta), the common spoonbill (Platalea leucorodia), the mute swan (Cygnus olor), the whooper swan (Cygnus cygnus), and others.The following species are of great economic importance: the Eurasian coot (Fulica atra), the Eurasian woodcock (Scolopax rusticola), various species of wild geese: the greylag goose (Anser anser) which hatches in the Delta, the white-fronted goose (Anser albifrons) and the lesser white-fronted goose (Anser erythropus), migratory birds and wild ducks – the long-tailed duck (Clangula hyemalis), the common goldeneye (Bucephala clangula), the common teal (Anas crecca), the widgeon (Anas penelope), the Northern shoveler (Anas clypeata), the tufted duck (Aythya fuligula), the gadwall (Anas strepera), the garganey (Anas querquedula), the mallard (Anas platyrhynchos), the red-crested pochard (Netta rufina), the ferruginous duck (Aythya nyroca), the pochard (Aythya ferina), etc., the last six of which are widely-spread species.The following are among the birds of prey which live in the Delta: the great cormorant (Phalacrocorax carbo) and the pygmy cormorant (Phalacrocorax pygmaeus), especially the former being a greedy fish eater. Numerous species of heron live in the Danube Delta: the grey heron (Ardea cinerea), the purple heron (Ardea purpurea), the squacco heron (Ardeola ralloides), the great bittern (Botaurus stellaris), which integrates perfectly into the surrounding environment in hunting or defensive positions, the black-crowned night heron (Nycticorax nycticorax), and others, as well as various divers. Examples of the latter are the black-throated diver (Gavia arctica), which visits the Delta between November and March, the very common great crested grebe (Podiceps cristatus), the red-necked grebe (Podiceps grisegena), and the black-necked grebe (Podiceps negricollis). To these we can further add the common moorhen (Gallinula chloropus) and the water rail (Rallus aquaticus). Migratory species include: the glossy ibis (Plegadis falcinellus), the collared pratincole (Glareola pratincola), the northern lapwing (Vanellus vanellus), the Eurasian curlew (Numenius arquata), the common redshank (Tringa tetanus), etc. Songbirds living in the reed and filling the Delta with their harmonious and enthralling chants include: the bearded reedling (Panurus biarmicus), the grass-warbler (Locustella), Acrocephalus warblers (Acrocephalus), and Luscinia birds (the bluethroat – Luscinia sveica). In the Delta, there is also a wide variety of birds of prey. Some of these are day-time birds, such as the white-tailed eagle (Heliaeetus albicilla), the osprey (Pandion heliaetus), the Egyptian vulture (Neophron percnopterus), the western marsh harrier (Circus aeruginosus), falcons and kestrels. Others, such as the owl, dominate the night-time sky, the many small mammals of the delta or the numerous ducks and moorhens being among the numerous choices of food. The Delta's large surfaces of reed are home to many valuable mammals for cynegetics. Wolves, foxes, wildcats, weasels, and ermines are frequent guests of the Delta. The wild boar is also common here. One can hunt for wild boars around Sulina, on the Caraorman spit and the Letea wood, as well as in other spits. Sometimes, wild boars cross breeds with regular boars that have been left free in the neighborhood. A very sought-after mammal for its rare fur, the Eurasian otter (Lutra lutra) can be found in Mila 23, in the marshes around the village C. A. Rosetti and in those around Crisan and Mahmudia. The European mink (Mustela lutreola) is very a common animal in the Delta, being a valuable asset for fur trade and having the nickname "the Tulcea mink". Starting with 1953, there have been references to the presence in the Delta of the raccoon dog (Nyctereutes procyonoides), which has a yellowish fur with lustrous black or brown hair endings, similar to wolves' fur, only softer. The same year saw the arrival in the Delta of the muskrat (Ondatra zibethica), an aquatic rodent which builds small lodges in the middle of marshes using fragments of reed and other material. Its quite rapid proliferation causes certain problems, since the muskrat appears to be a baneful animal, digging through the shores of spits and destroying fishing nets.

by Anca Adochiţei