The Danube Delta is part of UNESCO’s World Heritage and is classified as a Biosphere Reserve, at national level and as a national park at international level. At the Reservation level there was a so-called functional zoning, on which I do not insist now, one of these zoning bearing the name of strictly protected areas, which we will discuss in this article.
First of all, let’s clarify a bit, the complicated labeling of the Danube Delta because it often leads to confusion.
In 1972, the UNESCO (United Nations Educational, Scientific and Cultural Organization) proposal for the protection of cultural and natural property in the world was approved by the Convention on the Protection of the World Cultural and Natural Heritage. It is a very complex concept, if you want details about it, you can find it online.
It is a protected natural area to which an international rating is assigned and whose characteristics are defined by UNESCO, in accordance with the needs regarding the purpose of protection and conservation of an area of natural habitat and its specific biological diversity, within the program “Man and the Biosphere”.
Wetlands of international importance represent the territories and stretches of water that include different types of wetland ecosystems and meet the criteria for highlighting the wetlands of international importance of the Ramsar Convention, possessing a rich biological diversity and having an important role for aquatic birds.
The Ramsar Convention on Wetlands is an intergovernmental treaty (under the aegis of UNESCO) on wetlands as an international aquatic bird habitat. The treaty was signed on February 2, 1971 in the Iranian city of Ramsar and entered into force on December 21, 1975.
The declared objective of signing the Convention is to protect biodiversity and maintain a favorable conservation status of wetlands (standing or flowing water, swamps, ponds or seawater glosses that do not exceed a maximum depth of six meters) as a habitat for aquatic birds.
The Ramsar Convention aims to maintain the ecological character of the areas concerned, by implementing an ecosystem approach in the context of sustainable development.
According to the IUCN (International Union for Nature Conservation) standards, the National Park is a territory well defined by law, where certain rules imposed in order to protect the natural environment (fauna, flora and natural environment) from human activities are respected. The purpose is to protect the natural biodiversity and not the economic activities.
Within the functional zoning of the DDBRA, one of the positions is the strictly protected area and means: Areas that are mandatory protected and represent very little disturbed samples, representative for the natural, terrestrial and aquatic ecosystems in the reserve.
At present (March 2020), there are 20 such areas covering a total area of 50,904 ha (8.7% of the reserve area).
In some of these areas economic activity (limited) is allowed, in others the entrance is strictly forbidden. Let’s see what these areas are and why they need protection.
Roșca – Buhaiova area is located in the North of the Danube Delta, in the north of Lake Merheiul Mare, between Chilia Veche and Periprava. It consists of a complex of lakes, streams. The Roşcă-Buhaiova area has been on the list of natural reserves in Romania since 1970, and since 1979 has been declared a biosphere reserve (together with Letea Forest). It includes a great diversity of biotopes1 representative for the river Delta (floating and fixed plains, swamp marshes, lakes, riverine grit, the western edge of the Letea seagrass, the eastern edge of the Chilia continental shelf, natural brooks, floodplains, willow patches, etc.). The core of this area with a comprehensive protection regime is the Roşca and Buhaiova lakes and the related fauna. The Roșca – Buhaiova area presents a remarkable diversity represented by mammals: glass /otter, mackerel /mink, hermelina /stoat, bizam /muskrat, jackal, enot /raccoon dog, fox, wild boar, etc., of birds: the largest colony of common pelican in Europe, of the mixed colonies of herons, almost all species of ducks and small birds, characteristic of the Delta, as well as a rich fauna of invertebrates. The same rich diversity is present in the vegetation aspect. In addition to the wide tracts of reed, the stagnant aquatic basins /water areas… are invaded by species of water lily (white and yellow), the leg of the rooster (piciorul cocosului). In the nitrate-poor waters, from some japs /backwaters or water mains between the plains /small waters from the reed islands, the carnivorous plants Utricularia and Aldrovanda appear. The submerged flora consists of most known species and other continental waters. Almost all the European flora of amphibious plants is concentrated in compact shrubs /reeds lands.
The importance of maintaining this area as “strictly protected” is huge. Besides the protection of the vegetation, it represents the last bastion of the nest of the common pelican in the Danube Delta (implicitly in Romania). If in other countries (eg Bulgaria) /(Bulgaria), huge efforts are being made to create nesting conditions for this species that is particularly important for both the nature and the future of tourism in the Danube Delta, as a sustainable economic activity, we just have to keep alive this colony.
The major dangers to the Roșca – Buhaiova area are the vegetation fires that take place from autumn to spring, aroused by people without discernment, the unauthorized entry into the colony of negative elements entitled “wildlife photographers” and the unauthorized flights over the colony of small airplanes or other aircraft, during the nesting.
Entry into this area is strictly prohibited.
The area with integral protection, Letea, is located on the beam /levee with the same name, one of the oldest beams /levee of the Danube Delta.
Brought to the attention of scientists as early as the 1920s and with the cause supported by King Ferdinand, in love with botany and the Periprava – Valcov area (Valcov was part until 1940 of Great Romania), the natural forest area Letea was placed under protection as early as 1930, being among the first areas of Romania placed under a form of protection. In 1938 he changed his degree in natural reserve, following the model of the current Retezat National Park and entered the list of reservations in Romania, next to the Piatra Craiului National Park. It is the beginning of declaring special natural areas of our country as protected areas or natural / national parks. The first areas in Romania under protection, by Regina Maria /Queen Maria, in 1927, were the Consul Hill (the Queen’s favorite place of painting) and King Ferdinand’s meadow, from the Teilor /Lindens Valley, both from Dobrogea.
It occupies a little high relief over the rest of the Danube Delta, with fluvio-marine /river-marine dunes, parallel to the sea shore, which house the forest with the same name that represents a particular type of vegetation. The forest that develops in the space between the sand dunes, in the form of 10-250 m wide strips is mainly composed of: meadow oak, moss oak, white poplar, black poplar, meadow ash, ash of whitewater, white lime, elm and, very rarely, black alder. A feature of the area is the abundance of climbing plants that give the forest a subtropical appearance. The forest extends to the Black Sea naturally, through the avant-garde species: pigeon(porumbar) /Blackthorn, red dog(catina rosie) /Salt cedar, white dog(catina alba) /Sea buckthorn which in some parts, towards the coast, develops lush, forming true impenetrable dams. Other rare species are also found in the vegetal scrub /bushes: the sand fly /bindweed/morning glory, the sand log /toast. The fauna is represented by the white tailed eagle and bird of the forest, jackals, rabbits and about 1,600 species of insects identified so far. Also in the chapter on fauna should be mentioned the wild horses. The forest administration claims that there are around 2000 horses that cause serious damage to the forest, but no one calculates how much damage is caused to the forest by even more thousands of cows, sheep and goats grazing here.
Among the threats to which the protected area Letea Forest is was subjected, first of all, the tourism “made” by people lacking a minimum education. The tourist invasion of recent years has left deep traces in the landscape of Letea. Dunes trampled with ATVs, lanes(liana) /lianas snatched from trees by occasional tourists who had no idea why they arrived here. Fortunately, over the last 2 years more drastic protection measures have been taken, with only two visitor routes remaining open and a forester guarding the entry of cars into the forest.
Dual administration, ARBDD /DDBRA and RNP make it difficult to make any decision and carry out management plans for the area.
Entrance to this area is done in compliance with the rules: Following the tourist route, any activity is forbidden (including smoking!), Climbing in trees or on the lanes(liane) /lianas, plant collecting, loud noises (if you get in the way of the weirdness “guide” that comes with a speaker after him to be heard by tourists) please inform him about this.
Declared a strictly protected area in 2000, the area with full protection regime Grindul/levee and Răducu Lake is located in the central part of the maritime delta, in the south of the Letea beam /levee formations and in the north of the Sulina Branch. The area comprises freshwater lakes fed from the last arm(sau branch?nu stiu la ce se refera) /branch of the great «M», located in a typical area of development of the river-marine cliffs between Chilia and Sulina. The aquatic basins are surrounded by marine shingles with poor, mobile or poorly fixed soils, steppe meadows and temporary flooded areas. The Răducu and Răduculeţ swamps are home to an specific area with fish fauna, which by isolating the respective ponds ensures feeding and breeding conditions for several species of fish, including: tench, wels catfish /catfish, carp, perch or bream /common beam.
In the area of the reservation are indicated several elements of flora specific to the wet sandy areas, with species of: pipirig /variegated horsetail, balsam /Euphorbia palustris, mackerel or sea pear /Elymus sabulosus. (nu stiu daca astea sunt denumirele corecte)
The threats to which this strictly protected area is subject are the general ones, the burning of the reef and the entry of people in the area, for fishing, grazing or other activities.
The lake is located in the Şontea-Furtuna lake complex, comprising Lake Nebunu and the adjacent area, bounded by the Şontea stream to the south and the boundaries of Lake Nebunu to the west, north and east. Nebunu Lake and its surroundings constitute a small area of lake area, characteristic of the river delta, which hosts specific biocenoses2, adapted to large amplitudes of the flood wave. Good nesting conditions for ducks and snail food3 are ensured in this area during the summer months. Due to its isolation, the lake provides optimum breeding and breeding /growth conditions for the small-scale and shallow lakes.
Threats: “Tour operators” and fishermen entering during spring, when the waters are high, with motor boats in these places; the vegetation fires.
Entry into this area is strictly prohibited.
The area is located in the Roşu-Puiu lake complex comprising natural aquatic basins, Porcu lakes, Porculeț etc. The area was selected on the grounds that it comprises various forms of relief: beams /levee, jays /backwaters, depressions, floating and fixed plane/reed islands formations, halophile meadows4 and is characterized mainly by the existence of biocenoses adapted to eurihaline /reed living conditions5. The complex of lakes and fluvio-marine beams /river-marine levee also represents through the plains, flora and fauna formations specific to these predominantly seagrass biotopes, an important nesting place for dwarf /little bittern and small cormorant /pygmy cormorant in mixed colonies, as well as for the conservation of halophilic grasslands /halophilous meadows.
Threats: “Tour operators” and fishermen entering during spring, when the waters are high, with motor boats in these places; the vegetation fires.
Entry into this area is strictly prohibited.
The protected area of Caraorman Forest occupies the central part of the beam /levee with the same name, a marine beam /levee that includes the most developed and representative denuded dunes (not covered by vegetation) in the Danube Delta. The valuable nucleus /core value, with an area of approximately 700 ha, includes, along with a varied meadow arbor consisting of poplar, ash and oak, sub-tree of zalog /grey willow, willow, tamarind etc. The southern extremity of the forest preserves monumental oak specimens, with diameters between 4.20 – 4.70 m, over 400 years old. As in the Letea forest, plant associations are home to invertebrate animals, especially insects and vertebrates (mammals and birds).
Entrance to this area is done in compliance with the rules: Following the tourist route, any activity is forbidden (including smoking!), Climbing in trees or on the lanes(liane) /lianas, plant collecting, loud noises
The Sărături area is located between Murighiol and Plopu. The Sărături Murighiol Lake is located on the Danube terrace, about 2 km long and 500 m wide. The lake’s waters are strongly saline, of the chloro-sulfate type, characterized by the great wealth of zoos and phytoplankton. The brackish complex is home to colonies of terns, marsh terns and seagulls /gulls. Here they nest abundantly, the black-winged stilt, ducks of different species, the avoseta / ???, the large grebe /great grebe, black-necked grebe and red-necked grebe. During the winter, the late frost of the glitter of water (due to the brackish character) causes a high concentration of geese, which find shelter and abundant food here.
By 2019 it was a nesting area for the Mediterranean laridae / ???, but due to the drought, the lake’s waters declined strongly in 2019 and 2020, their nesting island joined the shore and the colony disappeared.
There are many threats to this area: the garbage dump in the vicinity and from which plastics permanently fly in the lake; the chemicals used in agriculture, on the slopes of the hills in the immediate vicinity and which, in the rain, reach the water; hunting poaching; grazing on the lake /the lake’s shore, especially when shepherds are accompanied by dogs that destroy nests and eat eggs and chickens /chicks; some “passionate” about photography that go beyond ethics and strongly disturb the birds, especially during the nesting period.
It is strictly forbidden to enter with the cars by the water’s edge /shore. You can enter on foot to the bird watcher, with discretion, without sudden movements and without noise.
It is the smallest strictly protected area of the Danube Delta. The area includes the Ariniş situated on both sides of the access channel /canal in Lake Erenciuc /Erenciuc Lake, being bounded on the south, by the Sfântu Gheorghe branch, on the north, by Lake Erenciuc /Erenciuc Lake, the eastern and western limits being the forest surface. This area is the only forest area in the Danube Delta where black alder (arinul negru) /the black elder grow compactly.
Unfortunately, compared to the period when the strictly protected area was set up, the number of alders decreased considerably.
The threats are: tree cutting, vegetation burning.
It can be visited from the boat; access on the shore is prohibited.
Popina Island is located in the north of Razim Lake, near the fishing facilities /fishermen settlements Iazurile and Sarinasuf and the village of Iazurile. Popina Island represents a remnant of the continental rocky beam /rest of rocky continental levee, with a height of 47 m, which was an important stopping place for migratory birds and nesting for the common shelduck until the cows grazed /start grazing. At present there is no shelduck on the island /At the moment there is no Common Shelduck nesting in the island. In the spring, in this area with poor and dwarf /small vegetation, birds of the swamp can be found, birds of the forest: the common nightingale, the black-headed bunting, the calandra lark. The thermal springs present on the northern shore of the island (not yet studied) give the island a bigger scientific interest. The invertebrate fauna (also under-studied) comprises rarities. In 1965, here was the spider black widow /here was found the Black Widow spider, but later it was not found again, a Mediterranean myriapoda was reported, Megarian banded centipede (Scolopendra cingulata) /??? but this aspect has not been studied enough yet. However, Popina Island is the only place in the world where we find the dobrogean cricket (Isophya dobrogensis), endemic.
It is the largest comprehensive protection area. The Sacalin-Zătoane area comprises the complex of lakes, streams /backwaters and rafts /levee, being located in the southern part of Dranov Island, with a total area of 19,340 ha, and the lagoon area between the islands of Sacalinul Mare, Sacalinul Mic and the continental boundary of the Danube Delta, with an area of about 2,070 ha. Located in the east of the Dranov depression, the Sacalin-Zătoane area is one of the oldest parts of the fluvio-marine delta, characterized by a succession of young, sandy marine cliffs /???, approximately parallel to the coast, alternating with shallow or isolated lakes and a intertwining of marine waters (on direct opening into the sea) with the fluvial ones (through canals and streams). The two main lakes, Zătonul Mic and Zătonul Mare, due to marine abrasion, are constantly widening their connection with the Black Sea. The lakes provide ideal conditions for the nesting of the mute swan and for the food of the limicole /??? species, also abundant, and on the island of Sacalin, where is the largest colony of sandwich tern. Both the water slides and the shores and the coastal beach are places of maximum concentration of the ornithofa during the spring-autumn migration. The crescent-shaped island of Sacalin, made up of sand mixed with shells, poor in salting vegetables, represents the most important nesting and migration area for a lot of bird species. The threats to which this area is subjected are also multiple: the vegetation firing, the entry of fishermen both in the Delta area and along the coastal cordon where they make fishing camps, grazing. Especially on Sacalin Island, the large number of cows greatly affects the birds that make their nests on the ground, being trampled on by the animals that graze.
Entry into this area is strictly prohibited. It can be seen partially, from the boat, in the area of Sfantu Gheorghe village, where you can go by boat inside the lagoon but it is strictly forbidden to land on the shore.
Located in the lagoon complex Razim-Sinoe, the area is a mosaic of slightly halophilic beams /levee and shallow lakes (Periteasca, Cosna, Pahome, Ranec, Leahova), which are in a process of continuous sweetening after the closing of the Gura Portiţei and the consolidation of the coastal beach. The characteristics are the biocenoses developed on the dry sand beams /levee, on the sands bathed by the sea or Lake Razim /Razim Lake, as well as the biocenoses adapted to large variations of salinity.
The reserve houses and provides nesting and feeding conditions for several species of migratory, passage or sedentary birds, among which: common shelduck (Tadorna tadorna), red-breasted goose (Branta ruficollis), greater white-fronted goose (Anser albifrons), lesser white-fronted goose (Anser erythropus), mallard (Anas platyrhynchos), dalmatian pelican (Pelecanus crispus) or common pelican (Pelecanus onocrotalus).
In the area of the natural reserve there are several floristic species, among which: sea kale (Crambe maritima), ochiul lupului(nu am gasit denumire in engleza) / small bugloss (Lycopsis arvensis), ghirin (nu am gasit denumire in engleza) (Suaeda splendes) /???, cypress spurge /spurge (Euphorbia seguieriana), Italian rye-grass (Lolium multiflorum) or hornbills (cornaci) /water chestnut (Trapa natans).
It is subject to the same threats as the Sacalin – Zătoane area and entry is strictly forbidden.
The area is represented by the eastern extremity of the Doloşman promontory near the town of Jurilovca, comprising the location of the ruins of the Greek-Roman fortress Argamum and the steep area of the cliff of this promontory, until the pumping station for irrigation Sălcioara.
The reserve shelters and provides feeding and nesting conditions for migratory, passage or sedentary birds, with species of: pied wheatear (Oenanthe pleschanka), common swift (Apus apus), eurasian stone-curlew (Burhinus oedicnemus), common house martin (Ptyonoprogne rupestris) or calandra lark (Melanocorypha calandra).
The presence of a mammal is noted in the area of the reservation: the marbled polecat (Vormela peregusna), as well as several species of reptiles (turtles, lizards, snakes) and frogs.
The vegetation consists of floristic elements with rare plant species, among which: the centaurea (Centaurea jankae and Centaurea tenuiflora), sânzianna (Galium humifusum), dianthus (Dianthus pseudarmeria), cosaci(nu am gasit denumirea in engleza) (Astragalus vesicarius), valentita (nu am gasit denumirea in engleza) (Tanacetum millefolium) or henbane (Hyoscyamus niger).
The area can be visited (on foot), without any noise and disturbing the birds and animals in any way.
Wolves beam is a maritime beam /levee that separates the waters of Lake Sinoe /Sinoe Lake from those of Lake Zmeica /Zmeica Lake, more precisely it is located in the middle of the lagoon complex Razelm-Sinoe, bounded on the northwest by the lakes Zmeica and Golovița /Lakes Zmeica and Golovița, on the north by channel /canal 5 and on the south and east – southeast of Lake Sinoe /Sinoe Lake, and at a distance of 40 km north of Constanta.
Due to its position, between the Razim and Sinoie lakes, with low relief elevations (0.5-1.5 m altitude) and a specific vegetation of sandy soils of marine origin, the area represents an important breeding and feeding refuge for birds. Especially during the autumn migration, the area becomes an impressive concentration of ornithological fauna and, in particular, winter guests (geese, ducks), because in Lake Sinoie /Sinoie Lake the water is saltier south of the Wolves beam /levee than north, towards Razim. Due to the low quotas and favorable conditions, the area is also of great importance for the natural reproduction of the fish of the species: carp, zander and common bream.
Threats are: Constant pressures on the reservation administration, for allowing construction in the strictly protected area, illegal hunting and tourists coming in summer in search of retired campsites.
Entry is strictly forbidden.
The Istria-Sinoie area is located in the south-western part of the Danube Delta Reservation, at the northeastern extremity of the Saele beam /levee and comprises the promontory consisting of the green shales on which the Histria archaeological ensemble is located and a portion of the Saele beam /levee, located between the Histria Fortress-Nuntaşi village road and the eastern part of the Saele beam /levee, having a length of about 6 km south. In the area there is a great variety of bird species: common shelduck, ducks and geese. The area also has a special archaeological value. The fortress of Histria was founded in 657 BC. / B.C. by the Greeks from Milet due, among other things, to the fish wealth of this area.
It is a sea beam that separates the waters of Lake Sinoe /Sinoie Lake (more precisely of the Razelm-Sinoe lagoon complex) from those of the Black Sea.
The area is valuable for the morphological configuration characterized by the succession of cords, dunes and lakes, with their predominance, oriented on a flat direction on the current shore line and having a disposition in the fan. The vegetation is characteristic of the coastal areas with salty sandy soil. It is important in the migration of birds and for their wintering, the saline waters of the area freezing at lower temperatures.
It is an area strongly threatened by construction and uneducated tourists who enter and camp in the wildest areas, destroying the nests of birds and frequently disturbing the wildlife.
Entrance is strictly forbidden in the protection area, and there is a barrier on the main road.
Rotundu Lake is located in the Somova-Parcheş lake complex, in the western part of the complex. The area is bounded on the east by Lake Telincea /Telincea Lake, on the south by the Dobrogean / Dobrudja’s horst, on the west by Lake Saon /Saon Lake, and on the north by the northern limit of Lake Rotundu /Rotundu Lake. Lake Rotundu /Rotundu Lake is a typical meadow lake in the flood zone of the Danube, the Somova-Parcheş lake complex being the last area of this kind not affected by embankments. The area of Lake Rotundu /Rotundu Lake is of particular interest, being representative for the study and conservation of biocenoses adapted to large amplitudes of the wave, as well as for the reproduction of cyprinidae.
The area covers the area between the Great Babies /Babintii Mari, Little Babies /Babintii Mici and Potcoava lakes, including Potcoava Lake, being located between the Gorgova and Obretinul Mic lakes, the northern limit being parallel to the Sulina branch. The area is characterized by the existence of a mixed colony of herons, glossy ibis, egrete(imi da pe net aceeasi denumire ca la starc), /egrets and pygmy cormorant. It is a nesting place for the little bittern, Eurasian bittern, gadwall, red-crested pochard, red-necked grebe, white-tailed eagle etc., as well as a feeding place for many species of birds. The area is also a place of refuge for otters, minks, stoats and wild boars. The fish fauna is represented by a number of endangered species – crucian carp, tench.
The area with complete protection regime, Lake Belciug /Belciug Lake is located on the island of Dranov, in the last meander of the Sfântu Gheorghe branch (km 20 – km 25) and comprises the lake itself, within the banks, at the maximum levels of the Danube. Due to the isolation and the great depth, about 7 m, the lake is a very favorable place for the conservation of some species of endangered fish fauna (crucian carp, tench, ide). The area is also an important feeding place for many species of ornithological fauna, represented by herons, egrets(e corect?), ducks, etc.
It is located in the northern part of Lake Sinoe /Sinoie Lake, near the boundary of the Grindul Lupilor /Wolfs Levee protection area. With an area of 0.6 ha and a length of 4,514m, the island in the form of an atoll delimits in the northwest of the lake a small bay.
Since 2010, a scientific reserve has been established around the island, consisting of the glitter of water ??? of Lake Sinoe /Sinoe Lake, up to a distance of about 1km from its center. The total area of the reserve is 117 ha, including the water slide. The scientific reserve is one of the two places in Romania that houses colonies of the Dalmatian pelicans (Pelecanus crispus) and the third largest colony of dalmatian /Dalmatian Pelicans in Europe, an endangered species worldwide. The island is an important stopping place for the Common Pelican as well (Pelecanus onocrotalus), but also for other species, especially aquatic birds.
Access by unauthorized persons is prohibited on the island and in the reservation area.
The Prundu Islands with birds are two nearby islands located in the southwestern part of Lake Sinoe /Sinoie Lake, near the shore. With an area of approximately 1.4 ha and a length of 5,468m, the islands are shaped like atolls.
Around the islands, a scientific reserve has been established since 2010, consisting of the water slide of Lake Sinoe /Sinoie Lake, up to a distance of about 1 km from the center of the area. The total area of the reserve is 187 ha, including water slide. The scientific reserve is home to a mixed colony of birds, the most important of which are the spoonbill (Platalea leucorodia) and the dalmatian pelican /Dalmatian Pelican (Pelecanus crispus). The islands are an important stopping place for the common pelican /Common Pelican (Pelecanus onocrotalus), but also for other species, especially aquatic birds.
Access of the unauthorized persons is prohibited on the island and in the reservation area.
1Biotope = a living environment with relatively homogeneous ecological characteristics on which a biocenosis develops. The structure of the biotope includes inorganic substances, geographical, mechanical and physical, physico /physic-chemical factors and the relationships between these factors. The structure of the biotope determines the configuration of the ecosystem; it can be characterized by different types of environment: continental, island, edaphic, aquatic etc.
2Biocenosis = the totality of living organisms, plants (phytocenosis) and animals (zoocenosis), which interact with each other and coexist in a biosphere (biotope), forming with it a whole unit and which is in a dynamic equilibrium dependent on that environment. It is characterized by a certain structure and functioning given by the pattern of the circulation of matter, energy and information.
3Limicole = Limicole or shorebirds are birds that live in the waterfront area, are good at flying for short distances, feed on aquatic animals that they remove from the ground, under rocks or from shallow water bottom, with the help of the beak.
4Halophile = high salt content. Halophilic organisms: organisms that are adapted to live in a salty environment.
5Eurihaline = with a high tolerance to the salinity of the environment.