[04] Byala Reka

Coordinates: 25° 58’ 32’’ E, 41° 22’ 57’’ N — Altitude: 316 m — Area: 30818 ha

Description: It comprises the Byala Reka drainage basin in the most southeastern part of the Eastern Rhodopi Mountains in close proximity to the Bulgarian border with Greece. The vegetation is highly varied and under a very strong Mediterranean influence. There are some well-preserved forests of Fagus moesiaca and Quercus dalechampii. Widely distributed are the mixed forests of Quercus virgiliana, Q. frainetto, and Q. pubescens, here and there combined with Carpinus orientalis and Acer monspessulanum. There are single or group of Pistacia terebinthus, Amygdalus communis, Castanea sativa, and others. The banks of the Byala Reka and some of its tributaries are grown over with Alnus glutinosa, Platanus orientalis, and willows. There is a great number of xerothermic bush communities of Mediterranean type, characterised by a considerable species variety, dominated by Phyllirea latifolia and Juniperus oxycedrus with some participation of Paliurus spina-christi, Cotinus coggygria, and Fraxinus ornus. Some places are occupied by single and comparatively low rocks.

The butterflies of the region are investigated well enough. The first results were published by Beshkov (1994, 1995). The reasons for including the region is the presence of important populations of 8 of the target species [see a list below], especially Pyrgus cinarae, Pontia chloridice and Lycaena ottomanus.

— Target species: Pyrgus cinarae, Zerynthia polyxena, Pieris ergane, Pontia chloridice, Lycaena ottomanus, Pseudophilotes vicrama, Glaucopsyche alexis, Melitaea trivia.

Protection & threats: The region comprises one protected area, declared as such for the preservation of endangered bird species and river bank habitats. The region is affected by human activities, mainly connected with the traditional cattle breeding and agriculture. The forest habitats are threatened by natural or man-caused fires, afforestation with alien wood species, and illegal cutting (especially along the rivers). In the past few years deforestation and wood coal production have become a highly profitable business. The building of embankments along the Byala Reka riverbed under a joint project with Greece has completely destroyed the tidal meadows and river terraces. The reduction of the number of grazing flocks and the cultivation of the pastures have led to the loss of valuable grass habitats. A potential threat can be the investment plans for the production of precious metals (gold and silver production by the cyanide technique). The intensive development of tourism during the last decade can also bring about some negative consequences if not managed properly.

Other remarks: In 1998 part of the territory was declared a CORINE area due to its European importance for the preservation of rare and endangered localities, plants and animals. In 2005 the territory was proclaimed an area of ornithological importance by BirdLife International. There have been established 167 bird species, 33 of which are included in the Red Data Book of Bulgaria. Although the region is characterised by high biodiversity, it is not sufficiently investigated. A new dragonfly species (Somatochlora borisi) has been described from this region, which also comprises one of the habitats of the newly-described moth species Nola ronkayorum. Some rare and conservationally important moth species have been established as well: Triodia amasinus dobrogensis, Eochorica balcanica, Lemonia balcanica, Trichiura verenae, Perisomena caecigena, Eumera regina, Nychiodes waltheri, Apochima flabellaria, Paradrymonia vittata bulgarica, Cryphia amasina, Cryphia rectilinea, Grammodes bifasciata, Odice arcuinna, Praestilbia armeniaca, Calophasia platyptera, Amphipyra tetra, Lithophane ledereri, Lithophane merckii, Griposia wegneri, Tiliacea cypreago christiani, Orthosia schmidti pinkeri, Leucania herrichi, Agrotis syricola, Euplagia quadripunctaria, etc. The last species was included in Annex II of the Habitats Directive of the European Union.