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The impact of the intensive agriculture on biodiversity of the Nature Reserve Havranka
VESELÁ, Miluše
Land is one of the most important natural resources. Intensive use of land for agricultural production and large-scale deforestation gradually violated natural land cover and exposed the surface to the effects of erosion, eutrophication, and degradation. This thesis focuses on the impact of soil erosion and subsequent water eutrophication that affects biodiversity in the nature reserve Havranka. The thesis also concentrates on the monitoring and impact assessment of crop rotation and tillage in the fields around the above-mentioned nature reserve and on erosion protection. The thesis was developed by means of literature research. In addition to the literature, crop rotation plans and photographs of the area of interest were used.
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Methods of reduction of excessive biomass of phytoplankton
CHADTOVÁ, Gabriela
The aim of this study was to prepare review of methods to combat over development of phytoplankton. The work also includes a critical evaluation of usability, efficacy and risks of these methods. The methods to combat over-development of phytoplankton can be divided into direct and indirect. While the direct methods acts directly against phytoplankton, indirect methods are based mostly on reducing the amount of nutrients available for phytoplankton growth. Both of these methods can be further divided to biological, physico-mechanical and chemical. The direct methods of physico-mechanical include ultrasound, flushing and dilution, direct chemical methods include the use of chemical algaecides, coagulants and flocculants. Direct biological methods are especially divided by the principle of parasites(viruses,bacteria and fungi), competitors (algae), allelopathy (extracts from higher plants),predation (protozoa and herbivorous fish). The indirect physico-mechanical methods include extraction and overlapping sediment. Chemical methods are meant by the binding of nutrients to insoluble compound in the sediment and the biological methods are meant use of communities of bacteria for mineralization of sediments. The next part of the work is devoted to the characteristics of algae and cyanobacteria, as well as factors affecting the formation and development of algal blooms. In this part of the work I focus mainly on cyanobacteria, their toxins and the effect they have on the individual components of aquatic ecosystems.
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Effect of P Enrichment on Rhizodeposit Quantity and Bioavailability: a Comparison of Two Macrophyte Species
KUBEŠOVÁ, Jaroslava
A review on plant rhizodeposition, nutrient uptake and interactions with rhizosphere microbial community is presented. Based on reviewed findings, a study on rhizodeposition rates and rhizodeposits bioavailability of two macrophyte species with different life strategies (stress-tolerator and competitor) was conducted. The effects of P addition and sediment type on rhizodeposition and microbial activity were examined. Research was carried out in tropical marshes of Belize; results from field were supported by C partitioning mesocosm study. This project was supported by NSF # 0089211 and ME 912.
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