66. Lake Vapsko-2, Rila Mountains (Bulgaria)

Lake Vapsko-2 (42° 04 ʹ 50.72" N, 23° 31 ʹ 11.50" E; 2250 m above sea level [a.s.l.]) is situated in the lower range of the subalpine belt in the southern part of the Rila Mountains, Bulgaria. The lake has a nearly oval shape with a water surface of 0.28 ha fed by the larger upper Lake Vapsko-1 and drains into the Vapa River. The surrounding steep slopes are covered by thick impenetrable stands of Pinus mugo Turra with some Juniperus sibirica Burgsd. within patches of herb vegetation (Ivanov 1964).The coniferous forest belt in this part of the Rila Mountains is dominated by Pinus peuce Griseb. admixed with Picea abies L. (Karst.) and Pinus sylvestris L. At lower altitudes, Abies albaMill. also occurs. The distribution of Fagus sylvatica L. below 1200-1000 m is fragmented, together with the oak forests (Tonkov et al. 2019). Theflat peaty shores of the lake are overgrownbyhummocks of Sphagnum spp., Carex nigra (L.) Reichard, C. rostrata Stokes, Trichophorum cespitosum (L.) Hartm., Deschampsia cespitosa (L.) P. Beauv., Nardus strictaL.,Eriophorum latifoliumHoppe,Parnassia palustris L., Veratrum lobelianum Bernh., Primula deorum Velen., Plantago gentianoides Sm., Pinguicula balcanica Casper, Pseudorchis albida (L.) A. Löve & D. Löve, etc. The climate is montane at the tree-line, the mean January temperature is -6°C while the mean August temperature is 11.4°C (Bozilova & Tonkov 2011).