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ŠUMARSKI LIST 1-2/2019 str. 37     <-- 37 -->        PDF

Floristic and microclimatic features of the Sovljak doline (Mt. Velika Kapela, Croatia)
Florističke i mikroklimatske značajke ponikve Sovljak (Velika Kapela, Hrvatska)
Tihana Vilović, Suzana Buzjak, Nenad Buzjak
The relation between floristic composition, microclimate and geomorphology of a large-sized karst doline was analysed in the area of the Sovljak doline located on the Mt. Velika Kapela. Habitat conditions in various parts of the doline, due to its morphology, were described in this work. Geomorphological observations, microclimatic measurements (including air temperature, relative humidity and dew point temperature data) and flora inventory were carried out. Ellenberg’s indicator values, life forms, chorological and taxonomical analyses were performed, as well as the analysis of habitat similarity. The doline slopes (northern and southern) appeared to offer different habitat conditions than its bottom, due to their morphological and microclimatic differences, which resulted in high taxa variability along short distances in the doline. Furthermore, the presence of temperature inversion promoted the development of the vegetation inversion, which is common in such large dolines.
Key words: microclimate, geomorphology, flora, Ellenberg’s indicator values, vegetation inversion
Dolines are natural enclosed depressions found in karst landscapes, considered as diagnostic landform of such landscapes. Besides their geomorphological context in karst, dolines are also described as interesting localities due to their special microclimatic, ecological and vegetational features. The climate of the dolines differs from the climate of the surrounding area, mainly because of the different amount of the radiation they receive, which depends on the exposition and inclination of the doline slopes (Cernatič-Gregorič and Zega, 2010). As a concave relief form, they favour the formation of air temperature inversion, more clearly expressed in dolines with greater depth, and in those situated on higher elevations (Šegota and Filipčić, 1996). Furthermore, microclimatic conditions influence the composition and distribution of vegetation, thus, air temperature inversion can also lead to the vegetation inversion in a doline (Horvat, 1962).
As a result of different type of genesis and evolution, dolines differ in their morphological features, which are the main criteria for their classification, together with their morphogenesis (Bondesan et al., 1992). Their horizontal dimensions may range from only a few meters, to a few hundred meters. With the sides ranging from gently sloping to vertical, their depth can vary from a few, to tens of meters. Morphogenetically, dolines can be classified into four main categories,