State: YambolArea: 34863,56 ха
Ownership: state - 39%; municipality - 25%; private - 36%;
Description:
Derventski Heights are a low-mountain hilly area with a mosaic of different habitats, located to the east of the Tundzha River. The state border between Bulgaria and Turkey passes along their main ridge. Their altitude is between 120 and 550 m. a.s.l. About 20% of the territory of Derventski Heights is covered by mixed broadleaved forests of oak, most often Quercus cerris and Quercus frainetto, at places mixed with Carpinus orientalis and Mediterranean elements. Mixed oak forests of Quercus polycarpa and Quercus frainetto occupy the southernmost parts of the region. The forest massifs are interspersed with open areas, overgrown with shrubs of Paliurus spina-christi and Jasminum fruticans, combined with xerothermal grasslands of Mediterranean elements, like Nigella damascena (Bondev 1991). The hills are divided by many small rivulet valleys with typical vegetation. Agricultural lands occupy also the low parts and the flat areas around the hills.
Birds:
The region of Derventski Heights supports 120 bird species, 25 of which are listed in the Red Data Book for Bulgaria (1985). Of the birds occurring there 59 species are of European conservation concern (SPEC) (BirdLife International, 2004), 2 of them being listed in category SPEC 1 as globally threatened, 17 in SPEC 2 and 40 in SPEC 3 as species threatened in Europe. The area provides suitable habitats for 45 species, included in Annex 2 of the Biodiversity Act, which need special conservation measures, of which 43 are listed also in Annex I of the Birds Directive. Well presented are species typical for mosaic habitats with significant open territories, but also these depended on small oak forest. The biggest population of Olive-tree Warbler Hippolais olivetorum in Bulgaria occurs in Derventski Heights. The area is one of most important in the country at European Union level for the breeding of Olive-tree Warbler, Lesser Spotted Eagle Aquila pomarina, Black stork Ciconia nigra, Marsh Harrier Circus aeruginosus, Montagu`s harrier Circus pygargus, Booted Eagle Hieraaetus pennatus and Black Kite Milvus migrans. It holds also significant populations of other threatened species at European Union level as Calandra Lark Melanocorypha calandra, Masked Shrike Lanius nubicus, Stone Curlew Burchinus oedicnemus, Greater Short-toed Lark Calandrella brachydactyla, Tawny Pipit Anthus campestris, Barred Warbler Sylvia nisoria, etc. The globally threatened Imperial Eagle Aquila heliaca also breeds in Derventski Heights.
Threats:
The area of Derventski Heights is used extensively by local people mainly for livestock and to less extend for agriculture and forestry. It is sensitive to intensification of agriculture and forestry, as well as change of land use practices. A decrease in grazing following by succession, as well as conversion of pastures to arable lands cause loss of grassland habitats for birds (Calandra Lark, Short-toed Lark Calandrella brachydactyla, Corn Bunting Miliaria calandra) and the Souslik Spermophilus citellus, which is the main food for the birds of prey, including the Imperial Eagle. The pesticides used there for agriculture are dangerous for birds. The dry grasslands are particularly vulnerable to fires both natural and artificial burning of pastures. During the dry years large parts of the site are burned by fires. The forests in Derventski Heights are relatively small patches dispersed amongst open landscapes. Forestry activities related to cutting affect directly many species of raptors, because the species use the old trees to build the nests. Illegal cutting, firewood collection and afforestation with non-typical species degrade the quality of forest habitats. One of the potential threats both to the habitats and to the birds in the area is the development of wind turbine farms.
Legal protection:
The area does not have legal protection by the national conservation legislation. In 1998 about 30% of the area is appointed as CORINE Site because of its European value for habitats, rare and threatened plant and animal species. In 1997 the area is appointed as Important Bird Area by BirdLife International.
