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Distribution patterns and habitat requirements of the species of the family Cobitidae in Slovakia
Pekárik, Ladislav ; Švátora, Miroslav (advisor) ; Ráb, Petr (referee) ; Matěna, Josef (referee)
Distribution patterns and major environmental correlations of the species of the family Cobitidae are presented here. All three species are still relativem widely distributed in Slovakia. Comparing with the past, no rapid ganges have been found. However, river regulation, pollution and the lowland amelioration affected the distribution of these species. Following the results of the occurrence of Balkan spined loach (Sabanejewia balcanica) within the mesohabitat scale, distance from source, slope, water depth and vegetation cover are the most influential variables in the proposed model. All these variables that contribute to our model explanation determine the stream morphology that affects the consequences of local temperature conditions and other abiotic factors as oxygen amount. Switching to microhabitat spatial scale, several microhabitat variables significantly influence the spatial distribution of analysed species. Depth more than 40 cm, refuges stones and point near bank (<15% of river width) are the most influential ones supplemented with substratum sand, substratum cobbles, substratum boulders, no refuges, refuges woody, depth 0-10 cm and maximum velocity none. Balkan spined loach occurs in the microhabitats occupied also by young-of-the-year (YOY) individuals and common minnow (Phoxinus...
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The effect of selected parameters of stream water on gill morphology of brook charr and the structure of ichthyofauna of the Jizera Mountains
Hušek, Jiří ; Dušek, Martin (referee) ; Švátora, Miroslav (advisor)
The occurrence of ichthyofauna on the territory of the Jizera Mountains (Northern Bohemia, Czech Republic) is limited, besides other factors, by the water chemistry. pH value and pH-related concentration of inorganic monomeric aluminum (Ali) are crucial parameters of the water, determining the survival of fish in streams. Low pH and high concentrations of Ali cause severe damages to fish gills. The thesis deals with the influence of the water chemistry on distribution of ichthyofauna in the Jizera Mts and gill morphology in brook charr (Salvelinus fontinalis), a dominant fish species of the upper plateau of the mountains. The results show that the species diversity of fish in acidified streams is lower than that in streams without meaningful acidic episodes. Histopathological analyses of gills of brook charr individuals from an acidified stream confirm, that low pH values and high concentrations of Ali have a cummulative effect and lead to degenerative changes on gills. Key words: The Jizera Mountains, ichthyofauna, brook charr, gill morphology, water chemistry, toxic aluminium, acidification
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Influence of environmental factors on fish assemblages in streams of the Elbe and Oder basins
Kůra, Luboš ; Švátora, Miroslav (advisor) ; Matěna, Josef (referee)
ABSTRACT The effects of environmental parameters on changes in the structure of fish assemblages were studied in the Elbe and the Odra river basin. Research was done at 819 sites that were surveyed in the field during the period between 1993 and 2007. The impact of 46 factors derived from the maps through a geographic information system was tested as well as the impact of 10 factors recognized in the field. To evaluate the influence of these factors the indirect (Detrended Correspondence Analysis, DCA) and direct (Canonical Correspondence Analysis, CCA) multivariate cluster analysis were used. Analyses were performed with data on presence-absence and relative abundance of each species. DCA well reflects changes in assemblages in the longitudinal profile of streams. CCA refers to a significant influence of regional and temporal variability and influence of individual factors. The fish assemblages are best characterized by the analyzed factors of distance from the source location, stream slope, altitude of locality, representation of arable land in the basin, number of ponds in the sub-basin above the locality, type of waters (salmonid or cyprinid), and water temperature (the only of the parameters of the field). The analyzed factors better reflect the variability in fish assemblages of the Odra...
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