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Natural archives of infilled lakes in the Třeboň Basin and the Bohemian Forest
Burda, Jan ; Vondrák, Daniel (advisor) ; Prach, Jindřich (referee)
In the territory of Czechia, lake sediments serve as invaluable natural archives, allowing us to study environmental changes in the Late Pleistocene and the Holocene. Understanding these changes is crucial for contextualizing various contemporary environmental issues and managing protected areas. Sediments from infilled lakes can also be used for research of past environmental change. The aim of this bachelor thesis is to summarize and compare the results of previous research on infilled lake sediments in the Třeboň Basin and the Bohemian Forest. Both areas contain basins with lake sediments dating back up to ca. 17,000 years. The thesis describes the principle of the formation of these lake basins, the regionally specific climate evolution, the evolution of soil and vegetation conditions in the lake catchments and the evolution of lake ecosystems. The history of the impact of human activities on the immediate surroundings of the lakes is also considered. So far, 32 infilled lakes have been found in the Třeboň basin and 3 infilled lakes in the Bohemian Forest. Another 9 lakes still exist in the Bohemian Forest. This review highlights the differences in the knowledge of the individual sites and the differences between the research carried out in the two areas. Keywords: lake sediments, Late Glacial,...
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Landscape-scale changes in central Europe around the Pleistocene-Holocene transition and the Anthropocene
Prach, Jindřich ; Pokorný, Petr (advisor) ; Kuosmanen, Niina Irina (referee) ; Roleček, Jan (referee)
This thesis investigates the dynamics of the central European landscape. Four case studies, exploring two key periods of environmental transformation: Late Glacial and the Anthropocene, are included. All case studies are connected by the spatial scale of interest: the landscape scale. This scale is targeted not only by the spatial extent of the sampling, but by the essence of the issues investigated, as broadly described in the introduction. The studies use disparate methods and different contexts, which helps to approach such a complex phenomenon - the landscape and its formation. The included studies are dealing with the Last Glacial landscape and vegetation by (1) comparing pollen records using modern analogues (here from Yakutia) and argues that the change at the Late Glacial/Holocene transition may not have been as great as previously thought, because at least somewhere forests may had existed during the Last Glacial being supported by permafrost melting. A follow-up study (2) explores how permafrost melting, i.e., thermokarst processes, generated an entire lake landscape whose remnants unexpectedly largely persist in the Třeboň region (southern Czech Republic) to recent times. This is followed by (3) the use of a detailed palaeoenvironmental record of the discovered lakes and their contexts...
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Relationship between pollen diversity and floristic diversity - utilization for study of the past
Koďousková, Lucie ; Kuneš, Petr (advisor) ; Prach, Jindřich (referee)
This thesis deals with the relationship between palynological diversity and floristic diversity. Diversity is complex quantity, which consists of a number of species, the number of individuals and relative frequency of species known as evenness. It characterizes the diversity at the species level, genetic level or within communities. Its relationship with palynological diversity is problematic, especially because of lack of taxonomic precision in palynology, species-specific differences in pollen production and dispersal and sample size, since the number of taxa increases with sample size. The thesis also focuses on the studies which tried to prove positive correlation between palynological and floristic diversity, including techniques used. The second part describes methodology of collecting vegetational and palynological data and the treatment of sampes.
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Forest vegetation changes in the Bohemian Forest during the second half of 20th century
Prach, Jindřich ; Kopecký, Martin (advisor) ; Sádlo, Jiří (referee)
Long-term forest vegetation changes were studied in the Bohemian Forest and its foothills. New vegetation relevés were taken at sites of typological plots established by forest engineers between 1955 and 1980. Data from 158 semi-permanent plots were analysed using modern statistical methods. The data show significant changes and homogenization of the vegetation. Ellenberg indicator values indicate eutrofication. Repeated measurements of soil pH suggest acidification, but the interpretation of these data is complicated by methodological problems. The forests under study exhibit high spatial variability. No main prevailing trend in vegetation changes was found. The changes are considered to be related to sulphur and nitrogen deposition and forest management. The influence of increasing age of forest stands seems to be unimportant. Discussed are not only vegetation changes and their possible causes but also the possibilities and limitations of using such old forestry data in botanical and ecological studies.
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Primary Succession - study methods and pollen analysis opportunities
Suk, Pavel ; Abraham, Vojtěch (advisor) ; Prach, Jindřich (referee)
This thesis focuses on the main study methods of primary succession. It compares their advantages and disadvantages, the scales of usage and the outputs they bring. Due to the duration of a succession development (in hundreds of years), indirect approach - space-for- time substitution using chronosequences (sites that differ only in age and make up succession series) is often used instead of direct study methods. Breach of the the critical assumption that all sites follow the same trajectory may lead to false conclusions about the successional development. This thesis presents examples showing this problem, ways to prevent it and offers an alternative method - pollen analysis. Pollen analysis is on average used for larger spatial and temporal scales but partially overlaps scales of space-for-time substitution. The thesis presents biases of pollen analysis and ways how to solve/limit them and introduces abandoned, partially flooded quarries as a suitable environment for the use of this method to study succession inferred from rapidly growing limnic sediment.
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Relationship between pollen diversity and floristic diversity - utilization for study of the past
Koďousková, Lucie ; Kuneš, Petr (advisor) ; Prach, Jindřich (referee)
This thesis deals with the relationship between palynological diversity and floristic diversity. Diversity is complex quantity, which consists of a number of species, the number of individuals and relative frequency of species known as evenness. It characterizes the diversity at the species level, genetic level or within communities. Its relationship with palynological diversity is problematic, especially because of lack of taxonomic precision in palynology, species-specific differences in pollen production and dispersal and sample size, since the number of taxa increases with sample size. The thesis also focuses on the studies which tried to prove positive correlation between palynological and floristic diversity, including techniques used. The second part describes methodology of collecting vegetational and palynological data and the treatment of sampes.
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Fragmentation and homogenization of forest communities in urban areas
Pevná, Tereza ; Vojta, Jaroslav (advisor) ; Prach, Jindřich (referee)
This bachelor thesis deals with issue of fragmentation and homogenization of forest communities in urban areas. The habitat fragmentation could be natural or anthropogenic. The main cause of the habitat fragmentation is currently human activity. We can count urbanization among the most significant of these activities. The extinction is one of the few effects, which is however very significant for the biodiversity of the fragmented habitat. The extinction of species in the fragmented habitat does not necessarily occur immediately. In the fragmented habitat, a decrease in the number of species can take place with some delay. There is another fact connected to the extinction in the fragmented habitat. The biotic homogenization can also occur in the fragmented habitat. The biotic homogenization is distinctive and easily observable particularly in urbanized area. Powered by TCPDF (www.tcpdf.org)
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Forest vegetation changes in the Bohemian Forest during the second half of 20th century
Prach, Jindřich ; Kopecký, Martin (advisor) ; Sádlo, Jiří (referee)
Long-term forest vegetation changes were studied in the Bohemian Forest and its foothills. New vegetation relevés were taken at sites of typological plots established by forest engineers between 1955 and 1980. Data from 158 semi-permanent plots were analysed using modern statistical methods. The data show significant changes and homogenization of the vegetation. Ellenberg indicator values indicate eutrofication. Repeated measurements of soil pH suggest acidification, but the interpretation of these data is complicated by methodological problems. The forests under study exhibit high spatial variability. No main prevailing trend in vegetation changes was found. The changes are considered to be related to sulphur and nitrogen deposition and forest management. The influence of increasing age of forest stands seems to be unimportant. Discussed are not only vegetation changes and their possible causes but also the possibilities and limitations of using such old forestry data in botanical and ecological studies.
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