Wetlands of international importance for Bulgaria

Transcription

1 Wetlands of international importance for Bulgaria Delcho Solakov Institute of Oceanology of Bulgarian Academy of Sciences, 9000 Varna, Bulgaria 1. Introduction In Bulgaria there are ten officially registered wetlands of international importance according to the Ramsar convention. Three of them (Ibisha Island, the Belene Islands Complex, and Srebarna Lake) are situated along the course of the Danube River, which marks most of the border between Romania and Bulgaria (Figure 1). The other Bulgarian wetlands of international importance are located along the Black Sea coast; two of them (Durankulak Lake and Shabla Lake) are in the north-eastern part of the country close to the border with Romania and the remaining five (Pomorie Wetland Complex, Atanasovko Lake, Vaya Lake, Poda Lagoon, and Ropotamo complex) are around the Gulf of Burgas (Figure 1). This chapter describes the main features of these wetlands and the reasons for their classification as Ramsar sites. Note that the co-ordinates of each site are given with reference to the geographical position of its centre. 2. Bulgarian wetlands located along the Danube River 2.1 Ibisha Island Ibisha Island (Figure 1, site 1) is a partially maintained reserve located in the River Danube. The co-ordinates of the site are N; E and the wetland area covers about 3.70 km 2. The whole island is covered with a seasonally-flooded riverine forest of Alnus spp., Salix spp. and Populus spp. It has been registered with the Ramsar Convention because it is an important example of a rare forested wetland habitat within the Danube catchment and as a breeding area of rare waterbirds including Cormorant (Phalacrocorax carbo), Pygmy Cormorant (Phalacrocorax pygmeus), Night Heron (Nycticorax nycticorax), Squaco Heron (Ardeola ralloides), Purple Heron (Ardea purpurea), and Spoonbill (Platalea leucorodia). Potentially damaging human uses of this wetland include forestry (based on non-native species) and illegal logging in protected areas; both activities cause habitat loss or damage and disturbance to nesting birds (Ramsar Convention, 2002c). NEAR Curriculum in Natural Environmental Science, 2010, Terre et Environnement, Vol. 88, , ISBN

2 130 NEAR curriculum in natural environmental science Figure 1 Locations of wetlands of international importance in Bulgaria. Wetlands along the course of the river Danube: 1, Ibisha Island; 2, Belene Island Complex; 3, Srebarna Lake. Wetlands along the Bulgarian coast of Black Sea: 4, Durankulak Lake; 5, Shabla Lake; 6, Pomorie Wetland Complex; 7, Atanasovko Lake; 8, Poda Lagoon; 9, Vaya Lake; 10, Ropotamo Complex. See text for co-ordinates of the various sites and Figure 2 for a detailed view of the Gulf of Burgas where sites 6 10 are located. 2.2 Belene Islands complex This site is a particularly representative example of a natural riverine wetland complex in the Danube River catchment. It has an area of about 70 km 2 and consists of one large island (Belene) plus a group of nine smaller islands located along a 16 km stretch of the River Danube (Figure 1, site 2; co-ordinates: N; E). Most of the surface of the islands is covered with seasonally flooded riverine forest of Alnus spp., Salix spp. and Populus spp. interrupted by several marshes and streams. The site has an exceptional biodiversity value because it hosts several rare species of plants (Nymphaea alba, Nymphoides peltata, Marsilea quadrifolia and Leucojum aestivum), five globally threatened species of birds (Pygmy Cormorant, Ferruginous Duck Aythya nyroca, White-tailed Eagle Haliaetus albicilla, Corncrake Crex crex, and Aquatic Warbler Acrocephalus paludicola) and the globally threatened invertebrate Hirudo medicinalis. It is also one of the most important breeding grounds along the Danube River for mixed colonies of herons, egrets, ibises and cormorants (6,000 9,000 pairs in the 1980s) and offers suitable stopover sites for about 20 migratory species of birds. The islands once had a significant role as a nursery for about 20 fish species and efforts are being made to reinstate their importance with a planned restoration project. Part of Belene has been utilized as a prison since Other activities in this part of the island include agriculture, farming and small-scale logging (Ramsar Convention, 2002b).

3 Wetlands of international importance in Bulgaria Srebarna Lake This lake is situated in north-eastern Bulgaria between River Danube km 393 and km 391 (Figure 1, site 3; co-ordinates: N; E) and is most famous for its colony of Dalmatian Pelicans. The total area of the protected site is about 13.5 km 2. The wetland associated with the lake has extensive reedbeds and is separated from the River Danube by a narrow strip of woodland. The lake is also connected with the river through a channel by which the water flow from the Danube to the lake can be easily regulated. During the nesting season, many species other than Dalmatian Pelicans breed in the reedbeds or the willow shrubs: e.g. Little and Great Egrets; Purple, Night and Squacco Herons; Spoonbills; Glossy Ibises; Pygmy Cormorants; Red-necked Grebes; Ferruginous Ducks (for which Srebarna Lake is the main breeding area in the country); Pochards; Garganeys; Whiskered Terns; and Penduline Tits. White-tailed Eagles, Black Kites and Levant Sparrowhawks, despite not breeding in the area, feed regularly around the lake. During the migratory season and in winter (if the lake is not covered by ice), many waterfowl (such as Greylags, White-fronted, Lesser White-fronted and Red-breasted Geese, Dabbling Ducks, etc.) rest at the lake accompanied by White-tailed Eagles and Rough-legged Buzzards (Ramsar Convention, 2002g). 3. Bulgarian wetlands located along the Black Sea coast 3.1 Durankulak Lake Situated in the north-eastern part of the country (Figure 1; co-ordinates: N; E), Durankulak Lake is one of the most significant wetlands along the Bulgarian Black Sea coast. The eastern part of the Lake is separated from the sea by a narrow sand strip, while agricultural land and small groups of trees surround its western and southern banks. The fresh waters of Durankulak Lake, the extensive reedbeds along the shore and the location of the wetland on the Via Pontica migratory route (the second largest migration path of birds in Europe) are some of the important features explaining the impressive avian richness of this site throughout the whole year. During the breeding season many birds associated with aquatic habitats (Little Bitterns, Purple Herons, Ferruginous Ducks, Marsh Harriers, Little Terns, etc.) choose this area for nesting. Great varieties of passerines (Red-backed and Lesser Grey Shrikes, Black-headed Buntings, Tawny Pipits, Calandra Larks, Bearded Reedlings, Warblers, etc.) also breed in the vicinity of this lake. This site has the highest density of Paddyfield and Moustached Warblers in Bulgaria. The territory around the lake is perfect for observing the soaring migration of storks and birds of prey in autumn or spring. However, the main popularity of Durankulak comes from the huge quantity of waterfowl (Black-necked Grebes, Pygmy Cormorants, Mute and Whooper Swans, Pochards, Tufted Ducks, Red-breasted Mergansers, Yellow-legged Gulls, etc.) inhabiting its waters during the winter months. At such times of the year, geese are the most numerous, numbering tens of thousands (primarily White-fronted and Red-breasted Geese), but

4 132 NEAR curriculum in natural environmental science White-tailed Eagles, Pallas s Gulls and Lesser White-fronted Geese can also be observed (Ramsar Convention, Undated). 3.2 Shabla Lake Shabla Lake is a coastal freshwater lake in north-eastern Bulgaria (Figure 1; co-ordinates: N; E) bordered by areas under cultivation to the west and south. A shallow lagoon, named Shablenska Tuzla and located south of the Lake, combines with it to form a single wetland complex. The Lake s waters are rich in fish and, combined with its large reedbeds and the mosaic vegetation of the nearby sandy dunes, provides ideal conditions for the presence of many water-associated birds during the nesting season (Grebes, Little Bitterns, Shelducks, Little Terns, Ferruginous Ducks, Crakes, Little Ringed Plovers, Tawny Pipits, Lesser Grey Shrikes, etc.). Many egrets, herons, diving and dabbling ducks, waders and sometimes pelicans occur in the area during spring and autumn migrations. The Shabla Lake region is famous worldwide for its wintering population of geese. More than 50,000 Red-breasted Geese (approximately per cent of the world s population) and 100,000 White-fronted Geese used to spend the severe winters there. Flocks comprising tens of thousands of geese can be observed grazing in the surrounding agricultural fields during the daytime. The waters of Shabla Lake are also of great importance in the cold months for many grebes, swans, ducks and gulls (Ramsar Convention, 1996). 3.3 Pomorie Wetland complex This lake is a hyperhaline coastal lagoon situated in the cape delimiting the northern part of the Gulf of Burgas (Figures 1 and 2; co-ordinates: N; E) and separated from the sea by a sand bar and man-made dyke. It is used primarily for salt production, but there is also a spa resort where mud excavated from the salt-pans is used for health treatments on people. The inhabitants of this lagoon are determined by its high salinity. Pomorie Lake is an important breeding ground for the Avocet, Black-winged Stilt, Kentish Plover and Little Tern. It is part of the Via Pontica migratory route, and is of special importance for observing soaring migrants (storks, pelicans and great variety of birds of prey), resting and feeding waders (stints, sandpipers, plovers, curlews, phalaropes, etc.) and many gulls and terns (e.g. Mediterranean, Little and Slender-billed Gulls; Little and Sandwich Terns, etc.). During winter, the lake and the adjacent sea area are perfect settings for many divers, grebes (especially Black-necked Grebe), Great Egrets, Bitterns, waterfowl (swans and diving ducks), gulls and waders (Ramsar Convention, 2002e). 3.4 Atanasovko Lake This shallow, hyperhaline lake is situated to the north-west of the town of Burgas (Figures 1 and 2; co-ordinates: N; E) and has been used for salt production since The wetland with the surrounding freshwater canals and marshes, reedbeds, salt pans and settling pools hosts many birds all year round. Due to its importance for biodiversity, the northern part of the lake (including a buffer zone to its south) was declared a natural reserve in 1980 and became a

5 Wetlands of international importance in Bulgaria 133 Figure 2 Detailed view of the Bulgarian wetlands located in the coastal region of the Gulf of Burgas: 6, Pomorie Wetland Complex; 7, Atanasovko Lake; 8, Poda Lagoon; 9, Vaya Lake; 10, Ropotamo Complex. Site 6 and 7 are not clearly visible on the figure and their approximate locations are delimited by the white rectangles; see text for exact coordinates (Satellite view image modified from NASA, public domain) Ramsar site in During the breeding season, it is of special importance for many warblers (e.g. Savi s and Cetti s Warblers) and waders such as Avocet, Collared Pratincole, Black-winged Stilt, Kentish Plover and also Sandwich and Little Terns. Atanasovko Lake lies on the Via Pontica migratory route and the variety of species (over 300 species recorded so far) and the astonishing numbers of birds attract birdwatchers, photographers and scientists from all over the world, especially during migrations. At such times, several large flocks of storks and birds of prey pass over the territory of the lake which represents a typical bottle-neck site of international significance. Thousands of White and Black Storks, White Pelicans, Honey Buzzards, Common Buzzards and Lesser Spotted Eagles can be observed on a single day. Among their huge flocks, are individuals of many other species such as Levant Sparrowhawks, Marsh and Montague Harriers, Booted Eagles, Short-toed Eagles, Red-footed Falcons, Hobbies, Black Kites and even vultures. Rare passerines such as Aquatic, Moustached and Paddifield Warblers also cross (and stop at) this site during migration along with Slender-billed Gulls, Mediterranean Gulls, Gull-billed Terns, Marsh Sandpipers, Stints etc. During winter months the territory of the lake is used primarily for feeding and resting by Dalmatian Pelicans Pelecanus crispus, Pygmy Cormorants, Great Egrets, a great variety of dabbling and diving ducks, as well as small groups

6 134 NEAR curriculum in natural environmental science of geese (Red-breasted, White-fronted and Lesser White-fronted Geese) and White-tailed Eagles. Atanasovko Lake also holds the Bulgarian record as the site with the most numerous sightings of the Slender-billed Curlew; one of the most endangered species in the world and considered to be almost extinct in recent years (Ramsar Convention, 2002a). 3.5 Poda Lagoon Although naturally formed as part of the Bourgas-Mandra firth (Figures 1 and 2; co-ordinates: N; E), several past human interferences (construction of an oil processing refinery in 1960, a barrage in 1963 and an international road in the early 1970s) have largely helped to define the present shape of this coastal wetland. Nowadays, Poda is a shallow water body featuring a variety of habitats (freshwater, brackish, haline and hyperhaline pools and flooded areas overgrown with aquatic vegetation) which all host a great variety of bird species. It was declared a protected area in 1989 and a Ramsar site in During the nesting season, the extensive reedbeds provide shelter for Purple Herons, Little Egrets, Spoonbills and Glossy Ibises occur in mixed colonies. Many crakes, warblers, Little Bitterns and even Marsh Harriers also lay their eggs within the reedbeds of this lagoon. Electricity pylons standing in the water, remnants of a disused electricity line, are also used for breeding by Great Cormorants. During migrations, the territory of Poda is of great importance for many egrets, herons, gulls, terns, waders and waterfowls. Impressive flocks of thousands of migrants (storks, birds of prey and pelicans) pass here in a narrow, never-ending stream. The winter species list is fairly long and interesting, comprising various grebes (five species), Dalmatian Pelicans, Great and Pygmy Cormorants, Bitterns, Great Egrets, swans (three species), Pochards, Tufted Ducks, White-headed Ducks, Smews, and White-tailed Eagles (Ramsar Convention, 2002d). 3.6 Vaya Lake This is the largest Bulgarian lake and one of four lakes of the Burgas wetland complex that surrounds the city (Figures 1 and 2; co-ordinates: N, E). The wetland, which is highly significant for biodiversity (especially avian), is a shallow freshwater brackish liman with associated marshy areas and extensive reedbeds (the largest in the country). Fish farm ponds, adjacent to the lake, are heavily overgrown by aquatic vegetation. Several IUCN (International Union for Conservation of Nature) red-listed species of animals (i.e. five invertebrates, four fish, four amphibians, three reptiles, five birds and three mammals) have been recorded at this site. Situated along the Via Pontica migration route, the site is an important stopover and staging site for a large number of waterbirds, raptors and passerines. Each year, during migration and wintering, more than 20,000 water birds congregate here. For the following species, the number of individuals exceeds the Ramsar criterion of 1 per cent abundance of the biogeographic population: Cormorant, Pygmy Cormorant, Dalmatian Pelican, White-fronted Goose Anser albifrons, and White-headed Duck Oxyura leucocephala. Fishing and sand extraction are practiced in the

7 area, but the most serious threat to this site comes from the country s only petrol refinery (Ramsar Convention, 2002h). Wetlands of international importance in Bulgaria Ropotamo Complex (formerly Arkoutino) This site is located on the southern Bulgarian Black Sea coast (Figures 1 and 2; co-ordinates: N; E) and represents a mosaic of various habitats including lowland river stretches and estuary, seasonally flooded riverine forest, broad-leaved deciduous forests, small freshwater and brackish lagoons, sand dunes, rocky shores and fjords, a sea bay, and sea inlets. The site provides refuge to many nationally and internationally IUCN red-listed species of plants and animals: seven globally threatened species of birds, two plant species, eight invertebrate species and seven mammal species. Rich endemic and relict flora and fauna are also recorded at this site. The main human uses are forestry, hunting and recreational activities. The site is a very popular destination for nature lovers (Ramsar Convention, 2002f). 4. Summary Bulgaria has two main wetland areas that are highly significant for biodiversity and especially for the bird life that migrates through these areas: the Danube wetlands and the Black Sea coastal lakes and lagoons complex. 5. References Ramsar Convention Undated Document, Durankulak Lake Ramsar Convention 1996 Information Sheet on Ramsar Wetlands (RIS): Shabla Lake Ramsar Convention 2002a Information Sheet on Ramsar Wetlands (RIS): Atanasovko Lake Ramsar Convention 2002b Information Sheet on Ramsar Wetlands (RIS): Belene Islands Complex Ramsar Convention 2002c Information Sheet on Ramsar Wetlands (RIS): Ibisha Island Ramsar Convention 2002d Information Sheet on Ramsar Wetlands (RIS): Poda Ramsar Convention 2002e Information Sheet on Ramsar Wetlands (RIS): Pomorie Wetland Complex Ramsar Convention 2002f Information Sheet on Ramsar Wetlands (RIS): Ropotamo Complex Ramsar Convention 2002g Information Sheet on Ramsar Wetlands (RIS): Srebarna Ramsar Convention 2002h Information Sheet on Ramsar Wetlands (RIS): Vaya Lake

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