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Phytogeographical analysis of distribution of selected xero-thermophilous herbaceous taxa along the Sázava River valley in Central Bohemia
Vlasák, Tomáš ; Černý, Tomáš (advisor) ; Boublík, Karel (referee)
This study is focused on a phytogeographic analysis of the distribution of selected xero thermophilous herb taxa along the Sázava Canyon in Central Bohemia. The research was done in 62 localities scattered along the major river stretch from Ledeč nad Sázavou to the confluence of Sázava with the Vltava Riever. The Sázava River was divided according to the river mileage into 8 even sections where there were 6 or 7 larger representative localities further selected. In each locality there was obtained the semi quantitative floristic inventory of species according to a pre prepared check in list with 57 taxa, further a detailed exploration of the locality was performed including the measurement of the area (in ha), direct perpendicular distance to the Sázava riverbed (in km), distance of the locality related to the river mileage, proportion of slopes of southern expositions, by means of conservative method using paper maps, calculation of the coefficient of variation of local altitudes (i.e. the assessment of vertical complexity), reading of geographical coordinates by tourist GPS receiver and finally a detailed determination of bedrock types at individual localities. The results were processed and then statistically evaluated in the program CANOCO software for multivariate analyses. The CANOCO program calculated that the influence of species composition in the given areas describes approximately 8.6 % of the total variability of individual species. This influence is proven to be statistically significant on the alpha level = 5%. The analysis, using observed data, calculated that 28.9 % of total variability of the vegetation composition in the studied floristic areas is influenced by the chosen variables. This work may serve as a comprehensive resource of the sites for future research, also it brings a valuable floristic data for the nature conservation purposes.
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