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Allelopathy of aquatic plants and its possible application to control cyanobacterial blooms
Kolářová, Anna ; Jandová, Kateřina (advisor) ; Kučerová, Andrea (referee)
The excessive growth of phytoplankton and the development of water bloom leading to the damage to aquatic ecosystems are becoming a more and more frequent problem. There are many methods to control the water bloom from which mainly those that use interactions of living organisms have been developing lately, with the utilisation of aquatic plant allelopathy being one of them. Allelopathy is a type of relationship between two organisms when one of them influences the other by secreting allelopathically active compounds in the environment. However, the effect of these secondary metabolites depends on many biotic and abiotic factors, which also has consequences for their potential use to control the water bloom. Although the results of many studies suggest that allelopathy can affect the community of phytoplankton, its role in aquatic ecosystems is still unclear. This thesis summarizes the knowledge about the occurrence of allelopathy among aquatic organisms, the modes of action of allelochemicals and the impacts of the key factors influencing the allelopathic effect. At the same time, it evaluates the prospects of using the allelopathy of aquatic plants to control water bloom and reviews experimental approaches to studying allelopathic interactions.
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Makrofyta v rybnících s různým typem rybářského hospodaření
FRANCOVÁ, Kateřina
Artificial fishponds have been an integral part of the European landscape for centuries. In addition to fish production, they provide important ecosystem services and habitats for biota, including macrophytes. The processes influencing macrophyte assemblages in fishponds are poorly understood and thus they were in the focus of this research. The opening study introduces thesis with a review of available information of historical development of fishponds and relation between fish farm management practices and fishpond macrophyte assemblages. Relevant socio-economic factors and possible effects of climate change are also explored. Comparison with similar wetland habitats shows that fishponds represent valuable systems harbouring many macrophyte species and a range of their rare and threatened taxa. The following study focuses on seasonal and inter-annual differences in vegetation in open water zones of nursery and main fishponds. The results show significant effect of the fishpond use type on macrophyte assemblages with strong decrease in macrophyte species numbers and abundance with increasing fish stock pressure. Stands of aquatic macrophytes commonly more developed in the nursery ponds in the spring of the first year of the production cycle, but variability could be found between ponds for example due to lower water level. While the results showed distinctions in water chemistry, sediment thickness, and adjoining land use, only transparency exerted a significant effect on macrophyte assemblages. Differences in other measured parameters were probably too small to be reflected in macrophyte species composition. Additionally, most macrophytes in our dataset show a broad ecological range. The last part of thesis reports analyses of plant species of reed bed and exposed bottom zones in the same selection of fishponds. As observed in the study of the open water zone, the highest species numbers and abundance were observed in the nursery ponds. The plants of reed beds were mostly affected by the width of the zone and shore slope. Lower slope in most fishponds often allowed development of the dense stands of Phragmites australis, which are highly competitive. They affect light and nutrient availability, produce a high amount of litter and so limit occurrence of other species. This as well as a position in the upper part of littoral, where they might not be affected by fish or water level disturbances so often, led to similarities in reed bed zones between fishpond types. In contrast more open reed bed stands with species such as Typha angustifolia and exposed bottoms allowed development of more species. The plants of exposed bottoms were affected by fishpond use type and adjoining land use type. The reason is lower fish stock pressure and more regular summer and/or winter drainage. Some fishponds or their parts did not have reed beds and exposed bottoms were then directly connected and influenced by surrounding landscape, e.g. ruderal and grassland species such as Barbarea vulgaris and Taraxacum sect. Ruderalia regularly occurred there. Application of fish farming practices is important not only as it is a part of the national heritage, but also to avoid pond terrestrialization. However, modification of farming techniques to best suit individual pond conditions and to adapt to climate change is recommended. Reducing fish stock density when relevant and limiting nutrient input from manuring and supplemental fish feeding may aid recovery of fishpond ecosystems including macrophyte species assemblages.
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Macrophytes of fishponds in agricultural landscape of selected part of Novohradské hory foothills
SOUKUP, Tomáš
Cílem terénní diplomové práce bylo určování a posouzení diverzity vodních a mokřadních druhů rostlin (makrofyt) v 46 sledovaných vodních nádržích v povodí řeky Vltavy a Malše. Vlastní botanický průzkum probíhal v podhůří Novohradských hor a zaobíral se druhovou identifikací vyšších rostlin ve vymezeném území vodních nádrží, pro které byla současně stanovena i listová pokryvnost dle Braun-Blanquetovy stupnice modifikace Westhoff & van der Makrel. Sběr druhových dat a definování listové plochy probíhalo vždy jen na úrovni vodního ekosystému s členěním na jednotlivé polygony (litorály) s charakteristickými stanovištními společenstvy. Získaná data se následně vizualizovala v mapách a tabulkách druhového zastoupení s přidělenou pokryvností. Z environmentálních ukazatelů se hodnotil obsah dodatkových živin v nádrži, velikost rybí obsádky, chov kachen, charakter a mocnost sedimentů, vodní stav, převažující zemědělské využití půdy v blízkém okolí, rozloha vodní plochy a hlavní spádové povodí dané oblasti. Zmíněné ukazatele (podmínky) se zaznamenávaly pro každou vodní nádrž a staly se podkladem pro další statistické hodnocení mokřadního ekosystému. Diplomová práce se skládá ze dvou částí - rešeršního zpracování problematiky rybničního hospodaření s dopady na doprovodnou vodní vegetaci a statistického vyhodnocení identifikovaných údajů. Ze sumarizovaných statistických dat vzešla skutečnost zvýšené diverzity druhů v povodí řeky Vltavy u částečně letněných rybochovných nádrží. Mapování a sběr botanických vzorků proběhl ve vegetační sezóně 2015, v období od konce měsíce května do začátku měsíce srpna.
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Growth of aquatic vegetation in fish ponds used for recreation - Bolevecká soustava near Plzeň.
Pták, Martin ; Duras, Jindřich (advisor) ; Potužák, Jan (referee)
The aim of this diploma thesis was to clarify the differences among three different ponds (Bolevecký, Třemošenský, Šídlovský) situated in Pilsen. All of the above mentioned ponds are recreational areas where Bolevecký pond is best known for his water quality improvements since 2006 (after application of Fe and Al - colagulants and also fish - stock changes). The main difference was based on the growth of submersed water plants. The macrophytes were growing slowly or not at all in Bolevecký pond. There was a huge expansion of macrophytes (mainly Myriophyllum spicatum species) in Třemošenský and Šídlovský ponds therefore the water plants must be regulated during summer seasons by mechanical harvesting. The water in all three ponds proves the same qualities but the differences may be found in the nutrient composition of sediments. The fractionation analysis (the founders Psenner and Puczsko) confirmed the fact that all localities are poor in phosphorus however the differences were found in content of iron. The increased content of iron was observed in sediments of Šídlovksý and Třemošenský ponds (mainly in BD fraction - the iron was unstable under redox potential changes). The result of this analysis proves that phosphorus is potentially more available for macrophytes in sediments of Třemošenský and Šídlovský...
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Monitoring of Duchcov selected ponds - riparian vegetation
Kotlanová, Jaroslava ; Pecharová, Emilie (advisor) ; Markéta, Markéta (referee)
The aim of this study was to conduct a site inventory survey of littoral vegetation and propose management measures to protect macrophytic vegetation. For this reason, a list of species of riparian vegetation found on the site has been made. According the processed pictures of macrophytic species we defined communities occurring in the area of interest which were drawn into the maps. The occurrence of the endangered and exotic species has been also monitored.
The monitoring was carried out on the territory of the ponds ofthe local organization of the Czech Fishing Union Duchcov. This site is located in Podkrušnohorská basin, which is struggling with the environmental load resulting from the brown coal mining. The results were compared with similar work from other locations. The reason was to assess biodiversity in the area of the interest. The created maps of littoral communities have been confronted with the maps of habitat processed by The Agency for Nature Conservation and Landscape protection.
The results of this study can report on the status of littoral vegetation in the area of interest and serve as the basis for further monitoring, enabling to asses long-term changes in the ecological stability of the region. The results may also assist the future strategic management measurement plan.
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Biodiversity and ecology of makrophytes in selected standing waters in the floodplain of the Lužnice river
DVOŘÁKOVÁ, Olga
This is a field study describing seven backwaters in the floodplain of the Luznice river. The backwaters include alluvial pools, river arms and oxbows which differ in their genesis, morfology, hydrological régime, macrophyte vegetation and chemistry of water and sediments. This study was carried out in the Trebonsko - Protected Landscape Area and Biosphere Reserve, South Bohemia, Czech Republic. The data of species composition of the vegetation on transects of the backwaters are supplemented by water and sedimet analyses.
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