Influence of the catchment area and management of the lake to the eutrophic and succession processes in the lake ecosystem - the case of fish ponds in the Draga Valley in the vicinity of Ig
Cycle of matter in lake ecosystems and the influence of loading with nutritional substances on eutrophic process are presented in the Graduation Thesis; abiotic factors are discussed, the role of planktonic and macrophyte vegetations and interactions that occur among them are described. In particular, the Thesis describes characteristics of eutrophication, ways of preventing it from appearing, especially bio-manipulation as a way of changing of biomass on higher trophic levels that by regulating the proportion between zooplankton and phytoplankton enables submerged macrophytes and leads to cleaner water. In connection with eutrophic process, land use in hydrographic hinterland, and the way of management, rules of succession process and its course dynamics in the lake ecosystems are presented. As well described is the influence of morphological characteristics of the lake to distribution of macrophyte vegetation and silting up. In the second part the existing conditions, management and problems in ponds in the Draga Valley near Ig are treated. In order to obtain a better insight into the condition of ponds, measurements of basic physical-chemical parameters with the Hydrolab Datasonder 4 probe were performed. Also, measurements of transparency with the Secchi Disc were carried out. Taking into account the results of the measurement, analysing of the existing condition of ponds and conditions for prospering of various biological communities, the regulation plan proposal is represented, whose basic purpose is improvement of the condition and renovation of the deserted ponds. Also given are basing points and directives for the management of ponds
