Terkos Basin This is an IBA in danger! 

Country/territory: Turkey

IBA Criteria met: A1, B2 (2004)
For more information about IBA criteria please click here

Area: 160,351 ha

Protection status:

Doga Dernegi
Most recent IBA monitoring assessment
Year of assessment Threat score (pressure) Condition score (state) Action score (response)
2016 very high unfavourable medium
For more information about IBA monitoring please click here

Site description

The Terkos-Kasatura Kıyılan (Coastline) IPA comprises a complex of aquatic and swamp communities, assoriated with Terkos Lake (one of İstanbul's most important drinking water reservoirs) and sand dune habitats, set in a hinterland of grassland, heath and coppice forest habitats. The coppice forest habitats are probably the largest surviving area of actively worked coppice (in good condition) in Turkey, and support what is believed to be one of the largest surviving traditional charcoal production enterprises in Europe. The site's flora is exceptionally rich: 575 vascular plant taxa have been recorded, and the floras of the freshwater and sand dune ecosystems are amongst the richest in Turkey. Over 73 local and nationally rare plant spedes occur, including 10 spedes listed on Appendix I of the Bern Convention, plus a further 8 Globally Threatened spedes. Amongst the most important wetland spedes are Stratiotes aloides, Vallisneria spiralis and Trapa natans, whilst notable sand dune spedes include Aurinia uechtritziana, Festuca beckeri, Isatis arenaria, Linum tauricum ssp. bosphori, Silene sangaria and Verbascum degenii. Overall, the IPA can be regarded as one of the most important areas of European dune, grassland, forest and wetland vegetation in Turkey, and is perhaps the single most important complex of habitats for nature conservation in Turkish Thrace.
The prindple threats to the site arise from water manipulation schemes (since c. 1995 the lake water has been supplemented with water from seven other catchments), afforestation of grassland and dune habitats, and construction of secondary homes (Byfield et al. 2010)

The Terkos Basin, which includes the Terkos Lake, is one of Istanbul's oldest water resources. The Basin is located to the north of Çatalca Peninsula which is mostly within the boundaries of the province of İstanbul. The KBA continues north within the boundaries of the Kırklareli province, until the Kıyıköy coasts. The Basin is surrounded by the Istranca Mountains to the west and the Terkos Lake to the east. The majority of the area is covered with forests (Eken et al. 2006).

The Terkos-Kasatura Kıyıları (Coastline) comprises a substantial tract of coastline, together with its hinterland of forest, associated with the ridge of hills that runs parallel to, and between 10 and 15 km. inland of, the Black Sea. The main peaks of the hills rise to between 300 and 400 m., and since their geology is largely acidic, they are today still almost entirely clothed with semi-natural vegetation. Whilst much of the landscape is composed of coppice forest, a series of exceptional open grass, heath and wetland habitats - most notably those associated with Terkos Gölü - add considerably to the interest of this mosaic of habitats.

The prindpal wetland within the site is Terkos Gölü (lake) and its assodated habitats. The lake itself was formed where the exit to the Black Sea of the Istranca (Binkılıç or Kanlıdere) Deresi and other smaller streams was blocked by a sand bar approximately 3 km. long and averaging 2 km. in width. The lake averages 2 to 4 m. in depth (up to a max. of 13 m.), and covers an area approximately 2500 ha. in extent. Its naturally forested catchment covers an area in the order of 600 km2 and accordingly the lake in freshwater, despite its close proximity to the sea. The forested nature of its catchment also ensures a high water quality within the lake, which is of considerable economic importance since this is one of İstanbul's prindpal drinking water reservoirs (Byfield et al. 2010). 


Key biodiversity
There are 17 plant taxa living in KBA. Some of them are breeding waterfowls such as: Ferruginous duck (Aythya nyroca), Lesser spotted eagle (Aquila pomarina), Little bittern (Ixobrychus minutus), and Squacco heron (Ardeola ralloides) are some of them. Most of them are endangered: Red breasted goose (Branta ruficollis), White-tailed eagle (Haliaeetus albicilla) and Greater spotted eagle (Aquila clanga). The lake hosts more than ten thousands birds in the same time in winter.

Leading important mammal species in KBA are Long-fingered bat (Myotis capaccinii), Mediterranean horseshoe bat (Rhinolophus euryale), Lesser mole rat (Nannospalax leucodon), and European ground squirrel (Spermophilus citellus). There is also Eurasian otter (lutra lutra) around Motor Deresi. Terkos lake is also important for amphibians such as: European fire-bellied toad (Bombina bombina) and southern crested newt (Triturus karelinii). KBA is also important for a kind of damselfly, Somatochlora borisii which is narrow expanded. (Magnin and Yarar, 1997). 
GLOBAL CONSERVATION CONCERN SPP. [8 TAXA] Asperula littoralis [END, V*], Centaurea hermannii [END, V], C.kilaea [END, V], Cirsium polycephalum [END, V*], Isatis arenaria [END, E*], Linum tauricum ssp. bosphori [END, E*], Silene sangaria [END, E], Verbascum degenii [END, E]
Aurinia uechtritziana [V], Cirsium baytopae [END, R], Crocus flavus ssp. dissectus [END, R], C.pestalozzae [END, R], Cyclamen coum [n/l], Erysimum sorgerae [END,n/l**], Himantoglossum caprinum [n/l], Peucedanum obtusifolium [END, n/l], Salvinia natans [R], Trapa natans [n/l], Vaccinium arctostaphylos [n/l], Veronica turrilliana [R]
Anemone blanda [V] , A. coronaria [V], Anthemis tinctoria var. euxina [n/l*], Atriplexpatula [K], Baldellia ranunculoides [R], Centaurea inermis [R], Chenopodium opulifolium [R], Cicendia filiformis [n/l], Comandra umbellata ssp. elegans [R], Corrigiola litoralis [V], Crambe maritima [E], Crinitaria linosyris [R], Cyperus hamulosus [n/l], C. odoratus [n/l], Elatine alsinastrum [n/l], Erysimum diffusum [K], Festuca beckeri [R], Fraxinus pattisae [V], Galanthus nivalis [V], Jasione montana [R], Juncus pygmaeus [RL Jurinea kilaea [R], J. macrocalathia [R], Leucojum aestivum [V], Lilium martagon [E], Linaria odora [V], Linum hirsutum ssp. byzantinum [V],Lythrum borysthenicum [I], L.portula [I], Malva pusilla [K], Montia minor [K], Najas marina ssp. marina [R], Nectaroscordum siculum ssp. bulgaricum [R], Ophrys bombyliflora [R], O.bucephala [n/l], Orchis papilionacea ssp. papilionacea [n/l], Pancratium maritimum [V], Parapholis filiformis [R], Paronychia echinulata [V], Polygonatum hirtum [R], Polygonum mesembricum [V], Radiola linoides [n/l], Ranunculus lingua [R], R. thracicus [R], Ruscus aculeatus ssp. angustifolius [V], Stratiotes aloides [R], Thelypteris palustris [R], Tilia cordata [R], Tournefortia sibirica [R], Vallisneria spiralis [R], Verbascum bugulifolium [n/l], Veronica scutellata [R], Viola canina [K] 
(Byfield et al., 2010).

Recommended citation
BirdLife International (2020) Important Bird Areas factsheet: Terkos Basin. Downloaded from on 04/12/2020.