Original scientific paper
Floristic, Microclimatic and Geomorphological Features of Collapsed Doline Japage on the Žumberak (Croatia)
Nenad Buzjak
orcid.org/0000-0001-8760-1906
; Sveučilište u Zagrebu, Prirodoslovno matematički fakultet, Geografski odsjek
Suzana Buzjak
orcid.org/0000-0002-1981-4886
; Hrvatski prirodoslovni muzej, Zagreb
Danijel Orešić
orcid.org/0000-0002-5809-085X
; Sveučilište u Zagrebu, Prirodoslovno matematički fakultet, Geografski odsjek
Abstract
Collapsed doline Japage is located in the western part of Žumberak Mt. (Fig. 1), formed in tectonically crushed Upper Cretaceous carbonate layers (limestone and breccia). Apart from karstification, which is evident in two speleological features, its development is today mostly affected by the slope processes (collapsing, landsliding and soil creeping). The length of the peripheral axis of the collapsed doline Japage is 64 m in the N-S direction, and 63 m in the E-W direction. In terms of dimensions, it is the largest such phenomenon on the territory of Žumberak. The depth between the lowest point of the periphery and the bottom is 15 m. The highest altitude difference is 37.7 m. The doline’s volume is 54.000 m3. The measurement of microclimatic parameters in Japage (carried out from 2007 to 2009) proved temperature inversion during the warm part of the year (Fig. 2). The relative air humidity is higher at the bottom, and lower towards the margins of the doline’s rim (Tab. 1). During the vegetation period in 2007 and 2008, the flora of Japage doline was also researched. Plants growing at various depths and expositions were registered, and a part of them was recorded in the profiles N-S and E-W (Fig. 5). The listed plants underwent the analysis of ecological indicator values and life forms. Altogether 59 plant taxa were registered (Tab. 2). Seventeen of them, i.e. 29% of the total number of the recorded taxa is protected by the Nature Protection Act, and three are listed in the Red Book of Vascular Flora of Croatia as near threatened (NT). The life form analysis showed the predominance of hemicryptophytes and geophytes, corresponding to the moderate climate zone Japage belongs to. Ferns were the predominant species, particularly in the lower part of the doline and at its bottom, which has less sunlight and higher air humidity and soil moisture compared to the doline’s upper marginal parts (Fig. 6). Based on the analysis of ecological indicator values of the doline’s floristic composition (Fig. 7), we came to the conclusion that the soil in Japage is moderately moist, mostly low acidic to alkaline. It is a shadowy habitat predominated by widespread plants that can grow in colline, mountainous and sub-alpine areas.
Keywords
ecological indicatory values; flora; geomorphology; Japage; microclimate; Žumberak
Hrčak ID:
67621
URI
Publication date:
30.4.2011.
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