Article

The biodiversity of higher plants in the Tchelkov Rid (W Rhodopi Mts) has been investigated. A total of 261 species belonging to 157 genera and 50 families have been found in an area of about 500 ha. The largest families are Poaceae, Asteraceae, Fabaceae, Caryophyllaceae, Lamiaceae, Rosaceae, Scrophulariaceae. The highest number of Sub-Mediterranean and EuroMediterranean geoelements in the studied region can be explained by its geographical position. The area is enclosed between two arms of Mesta River along which Mediterranean climatic influence penetrates into Bulgaria. Eighteen taxa of conservation concern are registered: 13 endemics (12 Balkan, 1 Bulgarian endemics), 6 species from the Red Data Book of Bulgaria, 2 species protected by the Law for Protection of Biodiversity, 1 from the IUCN Red List and 1 from the CITES. A new locality of the Bulgarian endemic species Sedum stefco Stef. is reported. That species is of a very restricted distribution, with small populations and weak reproductive potential.