[36] Skrino Gorge

Coordinates: 22° 55’ 55’’ E, 42° 9’ 2’’ N — Altitude: 608 m — Area: 11945 ha

Description: The region is situated between the villages of Nevestino and Boboshevo in the Skrino Gorge of the Struma River. The gorge is about 20 km long and belongs to the Struma Subregion of the Osogovo-Belasitsa physical geographic zone. It is composed mainly of pre-Palaeozoic and Palaeozoic metamorphytes, young Palaeozoic granites, Mesozoic and Palaeogene sediments, young vulcanites and Quaternary deposits. The uneven height of the relief in the area, its considerable indentation and exposition affect the coming air currents and bring about a variety of climatic conditions. The valley of the Struma River is characterised by well-defined features of the transitional continental climate. The region is characterised by a main winter maximum of snow thawing and by a longer influence of the north slopes snow cover on the surrounding mountains. The Skrino Gorge is part of the Northern Struma River Valley floristic region. Almost the whole Struma River in the Skrino Gorge is grown with natural river bank vegetation. Some parts are covered by scarce Typha angustifolia and Typha latifolia or Phragmites australis communities. The original vegetation of the Skrino Gorge from the village of Chetirtsi to the village of Vukovo is composed of deciduous forests of Quercus dalechampii, Quercus virgiliana, and Carpinus orientalis, in some places interspersed with well represented Paeonia peregrina. The rocky parts of the Gorge, which offer no conditions for the development of wood vegetation, are sporadically covered by derivative vegetation of xerothermic grass communities consisting of Dichanthium ischaemum, Poa bulbosa, Chrysopogon gryllus, and ephemerals. The bush vegetation has some Mediterranean elements like Juniperus oxycedrus and Paliurus spina-christi mixed with Fraxinus ornus. Some parts of the sunlit slopes are abundantly grown with Astragalus onobrychis. The banks of the Struma River are covered by tree species like Alnus glutinosa, which forms river bank forests of up to 60-year-old trees with a subforest and which does not grow outside the borders of the river banks. These parts are predominantly grown over with Alnus glutinosa, which mainly determines the character of the original vegetation. The Gorge also comprises some river bank strips of Salix alba and Populus alba of up to 60-year-old trees with a subforest. The white poplars form a habitat whose northernmost locality known up to now is the Skrino Gorge. It is not certain whether the Platanus orientalis strips growing in some places are of natural origin.

The region is very poorly investigated, but very promising. The reason for including the region is the presence of important populations of 4 of the target species [see a list below], especially Zerynthia polyxena.

— Target species: Zerynthia polyxena, Pseudophilotes vicrama, Scolitantides orion, Glaucopsyche alexis.

Protection & threats: The Skrino Gorge is not legally protected under the national conservation legislation. At the proposal of the National Museum of Natural History, BAS, the Skrino Gorge was chosen for a NATURA 2000 area. In 2005 a procedure for declaring it a protected area was started with excellent documentation and public discussions and with the full support of the local inhabitants. Nevertheless, the region was returned for revision to the Bulgarian Government without any argumentation. The one-year ban issued by the Minister of Environment and Water on all activities damaging the region has already expired. One of the threats to the region are the human activities, connected with the exploitation of the meadows and the pastures. The most serious threats are the mowing and cultivation of the meadows. The changes in the hydrological regime of the region lead to changes in the humidity of the meadows. There were and still there are investment intentions for the construction of cascades of small hydropower plants along the Struma River, which will cause irreparable damages to the river ecosystem and the river bank habitats.

Other remarks: Ten conservationally important and protected by law plant species and 6 species included in the Red Data Book of Bulgaria have been found in this region. The species Polypodium cambricum has been recorded only from the Skrino Gorge. Paeonia peregrina is put under a preservation regime. Some tree species of conservation importance are 60-year-old trees of white poplar, Alnus glutinosa, walnut, beech, etc. In 2002 the territory was declared an area of ornithological importance by BirdLife International. Despite the fact that the region is poorly investigated, there have been established 118 species protected under the Biodiversity Law, 127 species — under the Bern Convention, 41 species — under the Habitats Directive of the European Union, 56 species — under SPEC, 2 — under the Ramsar Convention, 22 — under the Washington Convention, 37 — under the Bonn Convention, 17 — under EMERALD, 6 — under the European Red Books, 7 — under IUCN, 20 — under the Red Books of Bulgaria, and 5 — under the CORINE BIOTOPES. The region is extremely rich in historical and cultural monuments of national and world importance and is very attractive to tourists. Because of the great number of ancient churches and monasteries, the region (where the birthplace of saint Ivan Rilski is) is also known by the name of the Bulgarian Sveta Gora. The ecological, research, and village tourism has already started to develop offering possibilities for the overall development of the region. Some of the projects are operating. There have been built ecopaths, visitors’ centres, sign and information panels, larger accommodation. The Struma River is used for water sports and fishing. The moths are not sufficiently investigated. The following more interesting moth species have been established up to now: Poecilocampa alpina, Phyllodesma ilicifolia, Neognopharmia stevenaria, Dasycorsa modesta, Lycia graecarius, Cilix asiatica, Peridea korbi, Simyra dentinosa, Autophila ligaminosa, Egira anatolica, Orthosia opima, Perigrapha i-cinctum, Perigrapha rorida, Euxoa conspicua, Arctia festiva. Many other species of conservation importance are expected to be found.