Koncept geodiverzitete obstaja že več kot 20 let. Večina metod vrednotenja geodiverzitete se uporablja za ugotavljanje geokonzervatorskega ali geoturističnega potenciala. Metode, s katerimi bi lahko ...vrednotili izobraževalni potencial geodiverzitete, so zelo redke. Glavni cilj našega članka je podati novo metodo vrednotenja geodiverzitete za določanje izobraževalnega potenciala proučevanega območja. Metoda je uporabna za učne namene, ko učitelji načrtujejo organizacijo strokovnih ekskurzij ali terenskega dela.
•Large differences in floristic composition of the plant communities were found.•Hydrological gradient highly correlated with plant diversity.•Calcium content and pH negatively correlated with plant ...diversity.•Hydrological gradient significantly influenced the composition of plant communities.
Plant communities and selected environmental parameters were studied at the intermittent Lake Cerknica. Seventeen plots (16 m2) were defined down a 600-m transect on a gentle sloping shore with an elevation decrease of 2.7 m, to investigate the different types of wetland vegetation characteristic of the different habitats. Vegetation was investigated using the standard Central European method. Soil samples were measured for pH, electrical conductivity, organic matter, total nitrogen, available phosphorous and potassium, cation exchange capacity, and texture. Large differences in floristic composition of the plant communities were found. Vegetation of mesic meadows was seen for the rarely flooded most elevated plots, with transition downwards to wet grassland communities from the alliance Molinion and from the alliance Deschampsion. The lower habitats with soils waterlogged until July were colonized by marsh communities, while community of emergent hydrophytes was at the lowest end of transect. Over 100 vascular plant species were recorded in the plots. Species richness increased with elevation and decreased with moisture, with >50 taxa in three most elevated plots, and 9–15 taxa per plot for the nine most frequently flooded plots. The hydrological gradient corresponded to the elevation gradient, and together with duration of flooding had a crucial role in shaping plant community composition, distribution and diversity. The flooding arose from Ca-rich lake water, while elevated habitats were rainwater fed, which the consequent enhanced nutrient leaching and lowered pH and electrical conductivity. This produced negative correlations between plant community diversity and species richness versus pH, Ca2+ and electrical conductivity, since these influences were overridden by hydrological gradient.
The Sentinel satellite constellation series, developed and operated by the European Space Agency, represents a dedicated space component of the European Copernicus Programme, committed to long-term ...operational services in the environment, climate and security. A huge amount of acquired data allow us different surveys. The paper considers the detection of changes in water levels in Lake Cerknica. The multispectral index has been calculated from Sentinel-2 data and transformed to a 3D point cloud. As shown by the results, symmetry measures of 3D point clouds could be used for the detection of water levels. Prediction functions using a genetic algorithm have been fitted, and the best result achieved was RMSE = 0.9824.
The article presents the revolutionary violence in the wider Cerknica area in 1942, i.e. in the territory of the former municipalities of Begunje pri Cerknici, Cerknica, Rakek and Sv. Vid. The ...violence was directed at the real, alleged and potential opponents of the communist revolution. There was a total of 47 victims of revolutionary violence, 39 of which were civilians. The article describes some cases of murder, robbery and arson carried out by the Partisan units.
Abstract
Agriculture has a great impact on biodiversity in Europe. Populations of farmland birds are declining due to both intensification and abandonment of agriculture. The purpose of this study ...was to determine the effects of overgrowing on the diversity of birds at Cerknica Polje. Six vegetation types were identified on eight survey plots (15.2-31.6 ha each): Short grass - regularly mown wet meadows; Tall herbs - stands of Common Reed Phragmites australis and Reed Canary Grass Phalaris arundinacea; Sparse bushes - stands of low woody plants; Dense bushes - dense stands of bushes; Meadows with trees - mown meadows with scattered trees; Bushes with trees - hedges, trees and dense stands of bushes. In total, 34 species were registered. The heterogeneity of vegetation types correlated positively with the heterogeneity of bird species. The highest density of breeding territories and species was established in Bushes with trees, the lowest in Short grass. No species were registered in all vegetation types, and only Tree Pipit was recorded in five out of six types. Twelve species were registered in only one vegetation type. Cerknica Polje is an important breeding locality for species with the highest breeding density at the national level (e.g. Corncrake Crex crex, Curlew Numenius arquata, Skylark Alauda arvensis, Whinchat Saxicola rubetra, Sedge Warbler Acrocephalus schoenobaenus). These species breed in specific habitats with different stages of succession. A managing plan for the area should therefore combine abandoned plots in different stages of succession and large regularly mown areas. Abandonment of agriculture at Cerknica Polje has led to the emergence of areas with bushes in different succession stages. Efforts should be directed at preserving large complexes of mown wet meadows.
This paper deals with the water balance of the Cerknica Polje. The results of previous investigations are compared with the calculations of inflows to and outflows from the polje made for the ...hydrological year 1975 (411 days). The calculation of the Cerknica Polje water balance is made on the basis of daily volume variations of Lake Cerknica, calculated using the water level data of the Stržen stream at the Dolenje Jezero gauging station and the digital elevation model of the Cerknica Polje (grid cell size 25 x 25 m). For the hydrological year 1975, total runoff from the Cerknica Polje catchment (475 km2) is estimated at 620 million m3 of water or 17 m3/s. In the observation year, the strongest lake volume increase in terms of discharge was 135 m3/s, whereas the strongest lake volume decrease was 60 m3/s. According to calculations, maximum possible inflow to the Cerknica Polje was 232 m3/s. In the hydrological year 1975, calculated mean outflow from the Cerknica Polje through ponor caves and ponors at the bottom of the polje was 23.69 m3/s and maximum calculated outflow was 91.75 m3/s.
The study presents natural hazards in Slovenia's karst, focusing on flooding in karst poljes. A specific study was done on the flood dynamics of two typical and connected karst poljes (Cerknica and ...Planina) of the Classical Karst region. In the case of particularly extreme hydrological conditions in the autumn of 2008, detailed analyses of the recharge-discharge regime and the interrelationship of flooding on the two poljes were done. Daily precipitation, discharge, and water level values from several monitoring sites were analyzed and cross-correlated, and additional hydrological analyses were done using a digital elevation model in order to acquire water level increase and decrease intensity, flood water volumes, and the extent of flooding and to understand the conditions controlling karst flooding. The results reveal that the hydrological functioning of the studied karst poljes is influenced by the hydrogeological and temporary hydrological conditions in the catchment area. The response of the binary karst system (i.e., the influence of autogenic and allogenic recharge) is especially distinct. The study shows that during extremely intense recharge, the reactions of karst aquifer systems to precipitation are as rapid as the response of surface waters (the water level of Cerknica Lake increased with an intensity of 38-63 cm/day or 55 m3/s respectively) while retention capacities are negligible. In contrast to flash floods, floods in karst areas may last from several weeks to several months. For the observed period a three-dimensional simulation of the flooding was made. At the maximum recorded water level, the volume of water on the Cerknica polje was 51 million m
3
, and 26 million m
3
on the Planina polje. The maximum extent of flooding on the Cerknica polje was 23 km
2
and on the Planina polje 9.5 km
2
. On the basis of the study, information was provided regarding future hazard mitigation. However, the study demonstrated that a sufficiently dense monitoring network is necessary to predict the occurrence and duration of floods with greater certainty.
The turnover of matter and through‐flow of energy in the intermittent Lake Cerknica is facilitated by the exchanging wet and dry periods, which either promote or suppress growth and development of ...organisms, depending on the season of the year. Any deviation from normal floods significantly affects the productivity of reed stands. Drainage of the lake prevents a constant presence of aquatic organisms, particularly planktonic species. Drying and wetting accelerates the decomposition of organic matter. The nutrient input into the lake by one surface tributary proved to be relatively high. The quantity of nutrients in the lake water is lower, however, because of the high buffering capacity of the densely vegetated ecosystem.
The basic hydrobiological conditions as well as the planktonic Rotifer assemblages of the Lake Cerknica (Slovenia) were investigated first time in 2004-2005. 16 taxa were found, most of them are ...frequent in Central Europe. The preliminary results suggest a pressing need for further research.
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