engleski

The role of environmental factors on the cave biodiversity in Dinaric karst: an example of Vjetrenica cave

The Vjetrenica cave is one of the most important caves of Dinaric karst with very high cave biodiversity, from diverse and specialized cave fauna to sprout-like microbial aggregates (Kostanšek et al, 2013 ; Ozimec&Lučić, 2009 ; Lučić, 2003). Why Dinaric karst comparing to other European regions has so high cave biodiversity? One possible explanation is that the in South-eastern Europe lower glaciation level in combination with much moderate climate, diversified geomorphology, and hydrology during the Pleistocene have resulted in a remarkable range of different underground habitats. If this is true, the important question about Vjetrenica cave remains: why this cave has so extraordinary biodiversity comparing to thousands of other caves of Dinaric karst with similar geological, hydrological and outside climate settings? The aim of this study is to argue that special microclimate and hydrological conditions define environment that slightly, but essential for biodiversity, differ from the most of the caves in this region. Vjetrenica cave has specific climate and hydrological conditions that vary trough the cave, but also have time component connected to hydrological regime, The interest in climatic features of Vjetrenica cave dates from 77 BC (Historia naturalis by Pliny the Elder) and lasts until today, with special focus to strong wind at the entrance of the cave. Systematic and quantitative measurements of cave climate in entrance and deeper parts started ten years ago with new speleological exploration and making a new cave map. Strong wind at the entrance (up to 9, 8 m/s in summer) is one of the key signals that suggest strong exchange of energy and materials with surface environment. Average annual air temperature is between 11.0 and 11.35 oC, depending on location in the cave. The highest temperature corresponds to Donja Vjetrenica passage (300 m from the entrance, -23 m deep) that has separate air temperature regime. Air temperature amplitude drops with distance from the entrance, but not so fast ; it is 3.45 oC at 520 m and 1.59 oC at Veliko jezero (1275 m). In Donja Vjetrenica it is only 0.87 oC. One of the factors that have big influence to climate conditions is periodical siphon at 1007 m. The closing of the siphon with water during wet season stops strong air circulation along the passage and at the entrance. Unlike the many caves in Dinaric karst, these conditions are not so stable, even over 1 km away from the entrance. These oscillations may be small but important switches that affect biodiversity.

cave climate; hydrology; cave fauna; biodiversity; Vjetrenica; Dinaric karst

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