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Nevstoupíš dvakrát do téhož rybníka aneb vývoj rybničních ekosystémů od Šusty k hypertrofii
Vrba, Jaroslav ; Benedová, Z. ; Jezberová, Jitka ; Matoušů, Anna ; Musil, M. ; Nedoma, Jiří ; Pechar, L. ; Potužák, J. ; Řeháková, Klára ; Šimek, Karel ; Šorf, M. ; Zemanová, J.
Shallow manmade fishponds in south Bohemia were used for fish production for centuries, however, their ecosystems have changed dramatically due to excessive nutrient loading and fish stocking. Preliminary results of ten sampled fishponds suggested their hypertrophic status at present, while their plankton structure and dynamics reflected the actual size/age class of fish stock consisting predominantly of common carp. Planktivorous fish (both young carp and whitefish) remarkably reduced abundance, size, and species diversity of crustacean zooplankton, in particular large daphnids, whereas larger carp itself did not cause such a strong top-down effect. All other plankton components, i.e. phytoplankton, bacteria, protists, and rotifers showed rather high abundance and diversity, and suggested a reasonable impact of various microbial processes and interactions in the recent hypertrophic ecosystems.
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