Phytosociological analysis of noble hardwood forests (Ostryo-Tilienion platyphylli) in the Karst and its neighbouring regions (SW Slovenia)

In SW Slovenia, at Gora under Železna Vrata and Petnik gorge near Branik – both on the northern edge of the Karst, in the collapse doline Orleška Draga at Sežana and under Brkinski Rob at the contact of the Karst and Brkini Hills, we conducted a phytosociological analysis of the stands whose tree layer is dominated by Tilia platyphyllos, T. cordata, Acer pseudoplatanus, Ulmus glabra, in places also Carpinus betulus and Ostrya carpinifolia, and classified them into three associations, Corydalido ochroleucae-Aceretum pseudoplatani, Paeonio officinalis-Tilietum platyphylli and Fraxino orni-Aceretum pseudoplatani. The latter was described as a new. Also new is a secondary large-leaved lime association Lamio orvalae-Tilietum platyphylli on the sites of montane beech forests (Lamio orvalae-Fagetum) in the Čepovan valley, at the contact of the Dinaric and sub-Mediterranean phytogeographical regions of Slovenia.

Detection of Cover Collapse Doline and Other Epikarst Features by Multiple Geophysical Techniques, Case Study of Tarimba Cave, Brazil

Reliable characterization of the karst system is essential for risk assessment where many associated hazards (e.g., cover-collapse dolines and groundwater pollution) can affect natural and built environments, threatening public safety. The use of multiple geophysical approaches may offer an improved way to investigate such cover-collapse sinkholes and aid in geohazard risk assessments. In this paper, covered karst, which has two types of shallow caves (vadose and fluvial) located in Tarimba (Goias, Brazil), was investigated using various geophysical methods to evaluate their efficiency in the delineation of the geometry of sediments filled sinkhole. The methods used for the investigation were Electrical Resistivity Tomography (ERT), Seismic Refraction Survey (SRS), Seismic Refraction Tomography (SRT) and the Very Low Frequency Electromagnetic (VLF-EM) method. The study developed several (2D) sections of the measured physical properties, including P-wave velocity and electrical resistivity, as well as the induced current (because of local bodies). For the analysis and processing of the data obtained from these methods, the following approaches were adopted: ERT inversion using a least-square scheme, Karous-Hjelt filter for VLF-EM data and time-distance curves and Vp cross-sections for the SRS. The refraction data analysis showed three-layered stratigraphy topsoil, claystone and carbonate bedrock, respectively. The findings obtained from ERT (three-layered stratigraphy and sediment-filled doline), as well as VLF-EM (fractured or filled caves as a positive anomaly), were found to be consistent with the actual field conditions. However, the SRS and SRT methods did not show the collapsed material and reached the limited the depth because of shorter profile lengths. The study provides a reasonable basis for the development of an integrated geophysical approach for site characterization of karst systems, particularly the perched tank and collapse doline.

Community composition and cold tolerance of soil Collembola in a collapse karst doline with strong microclimate inversion

The study compared communities of soil Collembola along the inversed microclimatic gradient of the collapse doline of the Silicka ľadnica Ice Cave (Slovakia) in spring and autumn of 2005. Kruskal-Wallis ANOVA and the Mann- Whitney test revealed significant differences in abundance between sites and both seasons. Significantly higher abundance means and species richness were observed at most sites during the spring compared with the autumn. NMS ordination documented a clear delimitation of communities with remarkably different soil microclimates. The community pattern of the coldest section of the gradient, with low species richness and high mean abundance, was analogous to communities living in the harsh alpine and polar soils. The collapse doline with inversed microclimate hosted a high number of species (72) and a broad variety of montane forms (13), thus documenting that these karst landforms enhance local diversity of edaphic Collembola and serve as local refugia of specialized cold-tolerant species. The cold tolerance of the four abundant species at the doline cold sites, namely Ceratophysella sigillata, Tetrodontophora bielanensis, Protaphorura armata and Desoria tigrina, was tested in the laboratory using one-hour exposition survival tests. Within a temperature range from -2.4 to -7.8◦C, T. bielanensis was the most cold-sensitive species, with a lethal dose LD50 of -4.4◦C, while D. tigrina was the most cold-resistant, showing LD50 of -5.8◦C.

Soil Collembola communities along a steep microclimatic gradient in the collapse doline of the Silická ľadnica Cave, Slovak Karst (Slovakia)

In spring 2005 we investigated the collembolan communities in the 50-m-deep collapse doline of the perennial ice cave Silická ľadnica in the Slovak Karst (Slovakia). Samples were taken at seven sites along a 117.5-m-long transect on the slope from the ice-bearing cave mouth at the bottom of the doline up to the terrain surface at 500 m above sea level (a.s.l.). The temperature above the soil surface (+0.6 to +13.6°C) positively correlated with altitude. Species numbers (ranging from 20–32) and diversity indices were highest at sites in the middle of the slope with rendzina and well developed organic profiles. A Kruskal-Wallis ANOVA revealed significant differences in abundance between the sites. Mean abundance near the permafrost zone at the bottom of the doline was significantly higher than at the sites further upslope. The abundances of some eurytopic and forest species were significantly correlated with soil temperature. Cluster analysis and the IndVal method indicated differences in the structure of Collembolan communities along the transect. The community at the coldest site had the lowest species richness and the highest mean abundance of individuals. A total of ten montane species were recorded, with a lower number near the permafrost zone compared to the micro-climatically more favourable middle section of the gradient.