Cave Invertebrates in Ponor Special Protection Area (Natura 2000), Western Bulgaria: Faunistic Diversity and Conservation Significance

Ponor Special Protection Area is one of the richest in caves areas in Bulgaria, with more than 70 horizontal and vertical caves hitherto known from its territory. Caves are scattered all over the mountain, but the regions of Tserovo, Zimevitsa, Iskrets-Breze-Dobravitsa and Gintsi are richest and form specific karst regions within the mountain. A total of 20 caves have up to now been explored from biospeleological point of view, in which 119 species of invertebrate animals are found. The places with the highest number of cave invertebrates with conservation value are: cave Dushinka near of Iskrets, cave Vodnata Peshtera near the Tserovo, as well as Dinevata, Svetata Voda and Krivata Pesht caves near the Gintsi. The Mesovoid Shallow Stratum (M.S.S.) is entirely unexplored. The paper summarizes also the agricultural practices that are harmful to the cave fauna, such as: dumping of garbage and carcasses of dead animals in precipices and caves; using the caves as storage places, dairy farms, mushroom cellars, or pens; pouring out of chemicals, as well as raw sewage or polluted water in precipices and whirlpools; excessive use of nitrogen fertilizers on the agricultural lands in the watersheds of karst springs. The endemic cave-dwellers Typhloiulus bureschi, Paranemastoma bureschi, Pheggomisetes globiceps, Plusiocampa bureschi, Niphargus bureschi and Bureschia bulgarica could be used as indicators for bio-monitoring and assessment of the effect of applied agro-ecological measures in the area.