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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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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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