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The impact of eutrophication on fish in running waters
Jeníšová, Karolína ; Horká, Petra (advisor) ; Frouzová, Jaroslava (referee)
Eutrophication belongs among be the most serious factors threatening freshwater ecosystems. Eutrophication is a result of excessive nutrient loading which comes mostly from both the point-source and diffuse pollution and agriculture, increased sediment loading from soil erosion, but also due to a presence of various types of impoundments, which, particularly in some areas, represent a significat part of nutrient supply. Although the effect of eutrophication on freshwater fish communities has been thoroughly studied in standing waters, very little attention has been paid to running water ecosystems. Among the processes with the most pronounced impacts on fish communities are increased phytoplankton growth and loss of macrophytes, low oxygen levels or anoxia, occurrence of toxic forms of nitrit and ammonia and elevated turbidity and subsequent light reduction. Whilst the diversity of fish communities is not usually affected, changes in structure of fish communities and decreased ecological quality has been detected with the increasing level of eutrophication. The most sensitive fishes are salmonids as they have high oxygen demands and are very sensitive to a toxic forms of nitrogen. Moreover they are visual predators highly affected by the increased turbidity of water environment. Percids are mainly...
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Application of stable isotope techniques for verifying the geographical origin of endangered plants and animals subject to international trade
Kopecká, Ivana ; Jandová, Kateřina (advisor) ; Horká, Petra (referee)
Elements in nature can exist in several versions, which differ in the amount of neutrons in the nucleus. These modifications are called isotopes. Neutrons have a neutral charge, but do not have a zero weight, therefore isotopes of a single element are differ in weight. Thanks to the sensitive analytical methods, we can discern that the isotope in the sample is contained in what quantity (mass spectrometry is used, from which to retrieve the ratio of stable isotopes in a sample). This can be used in many fields, such as in geology, food ecology, or discovery of geographic origin. The aim of the thesis is in the published literature to determine the extent to which the method of analysis of stable isotopes usable to verify the geographical origin of endangered species of flora and fauna subject to international trade, especially turtles of the genus Testudo. Turtles of the genus Testudo are protected by CITES treaty, which limits, enables and disables trading in endangered species so as to avoid their extinction caused overexploitation for commercial purpose. However, there is still an illegal trade that the supervising authorities are trying to detect and combat. Key words: traceability, provenance determination, authentication, CITES treaty
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Methane ebullition from Czech freshwater reservoirs
Novotná, Tereza ; Frouzová, Jaroslava (advisor) ; Horká, Petra (referee)
Methane is a non-toxic colourless gas created by decomposition of organic materials in anaerobic environments. Such processes take place at bottoms of rivers, dams and water reservoirs. The gas is then released to atmosphere where it contributes to the greenhouse effect. The aim of this thesis is to measure the ebullition flux of methane from selected water reservoirs Vranov and Vír (representing typical water reservoirs in the temperate area), analyze factors affecting ebullition, and compare the ebullition flux among these two reservoirs. The data were obtained via device Simrad EK60 split beam, preprocessed in software Sonar 5, and subsequently analyzed in statistical software R. While there is a great degree of variability of ebullition flux within segments of individual water reservoirs, the total ebullition flux is comparable in both water reservoirs (Vranov: 3,90 ml·m-2 ·d-1 , Vír: 4,22 ml·m-2 ·d-1 ) and not significantly different from each other (p = 0,40). When analyzing possible factors affecting ebullition; the water depth and the distance from the dam, it is necessary to take into account that these two variables are highly correlated which may hinder our ability to separate their effects. Indeed, in both Vranov and Vir the effects of these variables, while significant when studied...
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Use of stable isotopes in feeding ecology of fish
Inquort, Vít ; Horká, Petra (advisor) ; Musilová, Zuzana (referee)
Cyprinidae is an important family of fish as far as ecological and economical aspects are considered. Studying feeding ecology of this family in aquatic ecosystems and integration of the findings into the overall image of trophic relationships are the fundamental prerequisite for the right interpretation of its ecological role. Stable isotope analysis is one of the methods capable of elucidating such relationships. In this thesis currently used methods and approaches in applications of stable isotope analysis in feeding ecology of fish are summarized. These vary among individual authors and include sampling of different fish tissues and different methods of preparation of samples before analysis, e.g. lipid extraction or carbonate removal. Certain mechanisms and phenomena which need to be taken into account to avoid biased results are also outlined in this thesis, among all tissue turnover and isotopic routing in particular. In the thesis current findings on food resources, trophic level and trophic niche of cyprinid fishes in freshwater ecosystems based on stable isotope analysis were summarized as well. Despite such findings being partial to date and the potential of the method not yet being fully exploited in many species, stable isotope analysis provide an important and useful tool alongside...
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Factors influencing movement and behaviour of animals in riverine environment
Horká, Petra
Animals living in riverine environments are influenced by various abiotic and biotic factors which shape their behaviour. Among the most distinctive behavioural traits by which animals react and adapt to environmental variability is movement behaviour. In my study I focused on movement and distribution of several species and their response to environmental and anthropogenic factors. The thesis consists of two parts: the first part synthesizes studies on behaviour of European grayling Thymallus thymallus, Ide Leuciscus idus and an invasive crustacean Hemimysis anomala; the objectives of individual projects were to determine which environmental factors influence the species' behaviour and how. The first two chapters present extensive radio-telemetry studies which examined diel movements and migration of ide (one year observation in the River Elbe) and European grayling (study conducted in autumn-winter periods of three consecutive years in the River Blanice, focusing on differences between juveniles of wild and hatchery origin). The third study was also conducted in the Elbe and evaluated the diurnal behavioural patterns and spread of the Pontocaspian mysid shrimp Hemimysis anomala. The second part of the thesis consists of two chapters focusing on young-of-the-year (YOY) fish assemblages: the first...
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Factors influencing movement and behaviour of animals in riverine environment
Horká, Petra ; Petrusek, Adam (advisor) ; Matěna, Josef (referee) ; Kováč, Vladimír (referee)
Animals living in riverine environments are influenced by various abiotic and biotic factors which shape their behaviour. Among the most distinctive behavioural traits by which animals react and adapt to environmental variability is movement behaviour. In my study I focused on movement and distribution of several species and their response to environmental and anthropogenic factors. The thesis consists of two parts: the first part synthesizes studies on behaviour of European grayling Thymallus thymallus, ide Leuciscus idus and an invasive crustacean Hemimysis anomala; the objectives of individual projects were to determine which environmental factors influence the species' behaviour and how. The first two chapters present extensive radio-telemetry studies which examined diel movements and migration of ide (one year observation in the River Elbe) and European grayling (study conducted in autumn-winter periods of three consecutive years in the River Blanice, focusing on differences between juveniles of wild and hatchery origin). The third study was also conducted in the Elbe and evaluated the diurnal behavioural patterns and spread of the Pontocaspian mysid shrimp Hemimysis anomala. The second part of the thesis consists of two chapters focusing on young-of-the-year (YOY) fish assemblages: the first...
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Software STATISTICA and its Applications in Analysis of Categorical Data
HORKÁ, Petra
This thesis involves primarily advantages and disadvantages of using the software to other similar softwares, focusing on analysis categorical data and representation of selected statistical methods. The main purpose of this thesis is demonstration of options the software offers and the main focus is put on possibility of processing categorical data. Typical examples are shown whether the software can be used in practice as well as in accounting, economics and tax issues. All those information come from questionnaire and of selected companies.
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Sports hall
Horká, Petra ; Ing. Josef Puchner,CSc. (referee) ; Sýkora, Karel (advisor)
The goal of this master´s thesis is to design load bearing structure of a sports hall. The thesis is elaborated in two variants of the structure design of the sports hall for common types of sports (handball, footsal, tennis, volleyball, basketball). The ground plan dimension is 42 to 72 meters and the construction height is 8 meters. The construction is designed for the district of Brno city. In the structural anlysis there were the following main load bearing structural elements designed and examined: glue laminated timber truss, wood purlins, steel beams, rods and bracing, columns, which together with the transverse girders are linked and foot and anchoring. The selected variant is also further developed. Part of the work is drawing documentation of the choosen variant, disposition drawing and drawings of the selected details.
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