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Influence of ants on soil chemistry across biomes
Kostečka, Luboš ; Frouz, Jan (advisor) ; Jílková, Veronika (referee)
Ants are important ecosystem engineers. Their activity has direct and indirect influence on soil chemistry inside their nest through processes such as bioturbation or accumulation of organic matter and its decomposition by the microbial community. These processes depend on environmental conditions such as soil properties and climate. However, there has not yet been a comparison of this influence on soil chemistry across different biomes. The aim of this thesis is therefore (1) describe the processes through which ants influence soil chemistry (2) summarize the resulting influence on soil properties such as the concentration of nutrients and the pH level in the ant nests and the surrounding soil (3) find out whether there is a common trend to these influences across biomes, or if every biome has its own specific trend. The findings of this thesis point to the conclusion that while there is a common trend across biomes, it heavily depends on conditions such as nest structure, feeding strategy of a particular species and the climatic conditions of the given ecosystem. Key words: ants, soil, soil chemistry, biomes, nests, bioturbation, feeding strategy, macronutrients, pH, environmental conditions, climate
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SELECTED ASPECTS OF NEST BIOLOGY OF PODICEPS CRISTATUS IN POND BIOTOPES OF TŘEBOŇ BASIN
ŠKOLNÍKOVÁ, Hana
The aim of the submitted study was to evaluate the occurrence of great crested grebe (Podiceps cristatus) and its adaptability in the intensively used pond region depending on environmental conditions. The locality under consideration, Nadějská pond system, is situated near the village of Frahelž in Třeboň basin. The investigation was carried out in the years 2007 and 2008, and it was based on periodic counts of Podiceps cristatus on water surface and direct searching for their nests including monitoring of nest parameters. Then the measured parameters were statistically evaluated. In the years 2007 and 2008 the most nests were found on Víra pond or on adjacent ponds (Skutek, Láska). Podiceps cristatus preferred 11 to 20 hectare ponds. 55 % of nests were found in the favoured Typha angustifolia growth, 39 % of nests were found in Bolboschoenus maritimus growth and 5 % of nests in Echinochloa crus-galli growth. Within the years 2007 and 2008 94 nests and 283 eggs were found. The measured parameters of nests and eggs mostly corresponded to literature. In spite of abundance of food, represented mainly by weed species Pseudorasbora parva, and suitable littoral growth a very low success rate in nesting was found. In the year 2007 there was 1 young and in the year 2008 1,06 young for one nesting pair.
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Breedintg biology of great crested grebes (Podiceps cristatus) in different habitats in the Třeboň basin
HÝLOVÁ, Alena
The aim of this study is to determine some breeding and ethology aspects of Great Crested grebes (Podiceps cristatus) in two different habitats in the Třeboň basin. The first locality is Nadějská rybniční soustava (NRS). It means 14 high eutrophic fish ponds near Třeboň. The second locality is in Hálámky and it is the gravel pits area. There are 4 ponds with low eutrophic water. This locality is similar to lakes - the origin biotope of Great Crested grebes (Podiceps cristatus). There are still active outputs of gravel in some of Halámky ponds. This study is based on breeding aspects, such as bird quantity, observing and measuring. Observations were carried out in 2004 - 2006. Whole day ethology monitoring was made in 2006. The data in Nadějská rybniční soustava are collected every 14 days from March to November. The data in Halámky are collected on the month base. The parameters of nests were measured during the breeding season. It was draught of nests, height above water level, height of water column, diameter of nests, ``kotlinka{\crqq} - a place for eggs in nest, ``korona{\crqq} - a special part of the nest. We focused on the parameters of eggs such as width, length and number of eggs in the nest as well.
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