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The effect of grazing pressure on species richness, composition and productivity in North Adriatic Karst pastures
Sonja Škornik, Matej Vidrih, Mitja Kaligarič, 2010, original scientific article

Abstract: We studied the effects of sheep grazing intensity and abandonment on plant species richness and composition, plant life forms and the productivity of North Adriatic Karst pastures. The experimental sites were under controlled grazing regimes (heavy, moderate, light and abandonment) for 10 years. Data were collected during one season; plant species composition, the number of species and above-ground and below-ground biomass were evaluated. Species richness was significantly reduced with increasing grazing intensity and abandonment. The greatest differences in species composition were recorded for the heavily grazed site owing to the appearance of a group of grasslands species typical of nutrient-rich soil. Heavy grazing increased therophytes and decreased the proportion of chamaephytes and geophytes. Above-ground productivity at the season's peak was typical of subhumid grasslands (up to 500 g ▫$m^-2$▫) and was significantly the highest in the abandoned pasture. Below-ground biomass was significantly the lowest in the heavily grazed sites and the highest in those that were moderately or lightly grazed. We could conclude that grazing intensification and abandonment have significant effects on the structure of these pastures. Low- or moderate-intensity (4-7 sheep ▫$ha^-1$▫) grazing seems to be the most appropriate treatment since it can maintain the species richness and typical floristic composition of those pastures.
Keywords: botany, grasslands, pastures, Karst
Published: 07.06.2012; Views: 1027; Downloads: 64
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Genetic and morphologic variability of annual glassworts (Salicornia L.) from the Gulf of Trieste (Northern Adriatic)
Mitja Kaligarič, Borut Bohanec, Biljana Simonovik, Nina Šajna, 2008, original scientific article

Abstract: The genetic variability of four pre-determined morphotypes of Salicornia (S. patula, S. emerici, S. veneta and the "saline type") from 10 locations on the Gulf of Trieste coast were studied by means of ploidy level estimation using flow cytometry and by molecular DNA analysis of ITS regions of nrDNA and cpDNA. Two groups, the diploids and tetraploids, with matching nrDNA sequences, were recognized. Two types of cpDNA emerged among the diploids; one the same as in tetraploids. This incongruence between nrDNA and cpDNA sequences indicates a hybridization with tetraploid maternal progenitors and demonstrates the evidence for reticulate evolution. The morphometry, based on generative morphological traits, did not clearly separate the four morphotypes. However, the most important characters - length of the middle fertile segment, length of the lateral flower, width of the scarious margin of the fertile segment in the floral region, conform to two genetically recognized types: diploid S. patula and the widely distributed tetraploid S. emerici, also comprising the "saline type" and morphotype, known as a charismatic endemic S. veneta, a flagship species for nature conservation. Other discriminative traits for diploid and tetraploid morphotypes are parameters of the flowers (comparison of length of the central vs. lateral flower) and stomatal index. The determination key is also given. The tetraploid S. emerici is by far the most common species of annual glassworts in the area, occupying more extreme habitats than a diploid S. patula, which mostly forms monodominate stands.
Keywords: botany, coastal flora, Gulf of Trieste, morphological variability, Salicornia emerici, Salicornia veneta, Salicornia patula
Published: 07.06.2012; Views: 1350; Downloads: 80
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Last remnants of riparian wooded meadows along the middle Drava River (Slovenia) : species composition is a response to light conditions and management
Sonja Škornik, Nina Šajna, Branko Kramberger, Simona Kaligarič, Mitja Kaligarič, 2008, original scientific article

Abstract: In the present study, we investigated the species richness and species composition in relation to light and management regime in remnants of wooded meadows within the riparian forests along the middle Drava River in Slovenia. 41 plots of still managed and, at different time periods (<5 yrs, 5-15 yrs, >15 yrs), abandoned riparian wooded meadows (RWM) were sampled. In addition to vegetation relevés, light intensity (PAR) was also measured in plots. Within the still-managed RWM, two floristically distinct types were recognized using TWINSPAN analysis: meadow-like and forest-like. Light intensity differed significantly between types. The CCA of active RWM showed a significant relation between species composition and light conditions. The number of species per relevé on active RWM was negatively correlated with light intensity - in contrast to North European wooded grasslands. This could be explained by the influence of species-rich riparian hornbeam forests that contribute many understorey species, in contrast to naturally mesotrophic meadows. CCA of both active and abandoned RWM demonstrated that light was a good predictor of RWM species composition and that abandonment caused profound changes in floristic composition. The species turnover during succession was more pronounced in less shaded meadow-like RWM where more light-requiring (grassland) species occurred. Species richness was the highest in active forest-like RWM. There were no significant differences in species richness between active meadow-like RWM and groups of abandoned RWM. The remains of riparian forests stretching along the flood plains of Central and Eastern Europe are considered one of the most natural ecosystems in the prevailing agricultural landscape. But naturalness could be in many cases only the consequence of abandonment of ancient land-use practices, like grazing of livestock, cutting between the trees, litter collecting, etc. Examination of the middle Drava River in Slovenia suggests the need to recognize the remains of ancient cultural landscape.
Keywords: botany, meadows, wooded meadows, Drava river, species richness, abandonment
Published: 07.06.2012; Views: 1000; Downloads: 38
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Grassland ecology in changing climate and land use
Zoltán Tuba, Mitja Kaligarič, 2008, original scientific article

Abstract: This brief overview decribes some structural and functional (including carbon cycling) aspects of grassland ecosystems, in particular with regard to the effects of global climate change and changes in land use. Afterward the papers briefly introduce the papers devoted to the above mentioned topics, which were selected for this special volume. As we can see, authors studied different kinds of management (including abandonment) and different parameters of climate change (CO2 , temperature, rainfall, etc.). They consider predominately vegetation parameters, including the various plant traits, carbon cycling, soil respiration and different ecophysiological traits in simulated climate change. Dealing with different impacts of climate and/or land-use changes on multi-species systems, that grassland communities certainly are, is exceeding merely experimental synthesized-community or single-species approach on one side and classical vegetation studies on the other. The complex responses of natural communities, including those under FACE systems, are not easy to interpret and understand. The importance of non-linear dynamics during climate changes is emphasized by Bartha et al. (2008). In these selected papers, grasslands appear to be a very dynamic and plastic ecosystem. Grasslands are highlighted from a new, much more topical point of view. Linking ecophysiology and vegetation science, which is characteristic for our selection of papers, is a promising tool to deal with problems on the ecosystem level in general, not only addressing the global climate change and land-use issues.
Keywords: botany, vegetation, grasslands, climate changes, land use
Published: 07.06.2012; Views: 999; Downloads: 51
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Survival and expansion of Pistia stratiotes L. in a thermal stream in Slovenia
Nina Šajna, Maja Haler, Sonja Škornik, Mitja Kaligarič, 2007, original scientific article

Abstract: We report about successful winter survival of a tropical plant Pistia stratiotes in a natural thermal stream Topla in Slovenia in temperate climate zone in central Europe. Only 2 years after its first occurrence in 2001 P. stratiotes managed to cover most of the water body where the thermal springs cause an elevated temperature (>17 °C year round). Enhanced biomass production of this invasive species took place in spring and summer and new stolons were formed at the end of the vegetation season. Over the winter older rosettes decayed and only small rosettes survived besides new rosettes formed from stolons. Plants developed flowers in April through August. Observations in December revealed viable seed production and seed presence in the sediment.
Keywords: botany, water plants, tropical plant, thermal water, temperate zone, winter survival, plants trait
Published: 07.06.2012; Views: 1085; Downloads: 77
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Functional comparision of the sub-Mediterranean illyrian meadows from two distinctive geological substrates
Nataša Pipenbaher, Mitja Kaligarič, Sonja Škornik, 2008, original scientific article

Abstract: In this paper, floristic and functional approaches to the classification of different types of sub-Mediterranean illyrian grasslands of the association Danthonio-Scorzoneretum villose lalliance Scorzonerion villosae, order Scorzoneretalia villosae, class Festuco-Brometea) are compared. The data set includes table with 30 relevés from SW Slovenia, sampled in two contrasting geological bedrocks - flysch and limestone - and matrix with 18 treits determined for 119 plant species. We also tested an impact of different geological bedrock on the relative proportions of C-S-R plant strategies in the relevés. With DCA ordinetion, relevés from limestone and flysch were clearly divided in two groups. First DCA axis suggested a gradient of soil humidity and pH. On the basis of selected traits, 5 Plant Functional Types were clustered and interpreted with Twinspan analysis. PCA ordination of relevés on the basis of plant functional traits revealed that samples from limestone could be separated from those taken on flysch substrate also with functional approach. Reievés from limestone tend to have bigger shares of species, which propagate by seed and vegetatively, and competitors and herbs. Nevertheless, it could be concluded that there are no major functional differences between meadows from both geological substrates. The positions of all relevés in standard C-S-R temary diagram showed that that the relative proportions of C-S-R functional types were not influenced by different geological bedrock.
Keywords: botanika, vegetacija, travišča, suhi travniki, rastlinski funkcionalni tipi, severni Jadran, C-S-R strategije rastlin, botany, biogeography, vegetation, grasslands, dry grasslands, classifcation, North Adriatic, C-S-R plant strategy
Published: 10.07.2015; Views: 617; Downloads: 11
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