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Latitudinal gradient of biodiversity and its dependence on rate of ecological processes and evolutionary processes
Krupička, Jan ; Storch, David (advisor) ; Kubička, Lukáš (referee)
Unevenness in the distribution of species diversity on the surface of the earth is one of the most striking phenomena in ecology. Latitudinal gradient of biodiversity could be explained by different rates of evolutionary processes such as speciation and ecological processes that control the ratebof extinction. The goal is to collect and evaluate the literature on the temperature dependence or latitudinal trends in the rates of these processes. Matabolic theory of biodiversity serves as the best explanation of the rates of evolutinary processes and their dependance on temperatur, while an explanation of the rate of ecological process is lacking in empirical data and theories that would put them in relation to temperature and latitude. Explanation by More individual hypotheisis was proved unconvincing.
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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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Influence of understory light on diversity and composition of forest vegetation in the České Středohoří Mts.
Macek, Martin ; Kopecký, Martin (advisor) ; Černý, Tomáš (referee)
Light is essential component of forest ecosystem, as limited light availability in forest-floor restricts herb and tree seedlings growth. Importance of light availability for maintaining plant species diversity and community structure wasn't sufficiently evaluated in the Czech Republic. This study focus on the ecological relevance of light availability on both landscape and local scale. Relationship of light to cover, diversity and species composition was quantified in the thesis. Dominant tree species affected light availability and its spatial variability. Light availability was along the soil reaction and slope most influential factor for large-scale species diversity. Within-site light variability affected plant diversity more than soil reaction variability. Measuring light by means of hemispherical photography seems to be an appropriate for studies like this. Light availability influnence on community compostition is weak in comparison with other environmental gradients.
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On the Nothernmost and Southernmost Limits of European Land Snail Spatial Ranges
Křepelová, Lucie ; Juřičková, Lucie (advisor) ; Horsák, Michal (referee)
The aim of this work was to evaluate the limits of ranges of European land snail species along the north-south gradient. To work out the document it was necessary to prepare the set of digitalized maps, that enabled to create the database of ranges of the individual land snails species. Based on obtained data I tried to identify places where the northern and southern borders of species ranges are the most frequent. The landsnails' ranges are affected not only by particular life requirements of the individual species (potential limits), but also by other conditions, especially climatic, geographical and historical (truncated limits). In this work I focused on their differentiation. Above mentioned process also enabled me to track the north- south changes in species richness of the landsnails taking into consideration the truncated and potential limits. The most important natural barriers constraining that numerous of species cannot naturally widespread from the south to the north are the Scandinavian Mountains, the Alpes and the Carpathians and suprisingly also southern borders of german and polish lowlands. On the other hand, spreading of the species form the north to the south is limited only by the Alpes. I also tried to distinguish the group of species whose ranges are not influenced by these...
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Exploring the relationship between species richness and intraspecific trait variability.
DVOŘÁKOVÁ, Hana
This thesis was originated as a contribution to the wide range of biodiversity studies published recently. It focused on the little explored importance of intraspecific variability in plant communities. A pot experiment hold in glasshouse environment was designed to observe influence of biotic interactions in mixtures of various species diversity on species functional traits and productivity. Variability of functional traits of individual species was assessed in relation to increasing species richness and the contribution of within-species variance to the total variance of pot communities was evaluated at different richness levels.
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Trophic relationships between insectivorous birds and insect in Papua New Guinea
TVARDÍKOVÁ, Kateřina
The thesis describes diversity of birds along a complete altitudinal gradient and in forest fragments in lowlands of Papua New Guinea. It focuses separately on the diversity of different feeding guilds, and discusses their links to habitat and food resources. More specifically, it focuses on forest insectivorous birds, their predation pressure on arthropods, feeding specializations and preferences, and some of the ways how insectivores search for food.
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Vegetation succession in old fields at broad landscape scales
JÍROVÁ, Alena
This thesis is focused on succession in old fields in Central Europe. Repeated sampling, analysis of surrounding vegetation and soil measurements were conducted in the Bohemian Karst Landscape protected area. Samples from the Doupovské hory Mountains and the rest of the Czech Republic were added to discover basic principles of old field succession at the larger scale of landscapes.
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Diversity and ecology of arboreal ant communities in a tropical lowland forest
KLIMEŠ, Petr
The thesis focuses on the study of arboreal ant communities in a highly diverse tropical rainforest in Papua New Guinea. In the first study of its kind, whole patches of forest were sampled extensively for ants foraging and nesting in tree trunks and canopies. An extraordinary amount of material collected from 684 felled trees and 260 bait stations in plots of primary and secondary forest was used to study the mechanisms structuring the diversity and species coexistence of this ecologically important insect group at the local scale. The first chapter addresses the question "Why are ant communities more species rich in primary than in secondary forests?" and explores the main environmental traits that influence their diversity in tropical trees. The second chapter compares the community diversity and composition and nesting preferences of ant species between both forest types. The final third chapter introduces a novel method, involving large-scale manipulation of ant communities that could serve as a template for future studies focused on complex tropical food-webs of canopy arthropods and plants. In summary, the results of the thesis highlight the importance of primary vegetation in conserving the diversity of native ant communities and the relevance of nesting microhabitats and their turnover between trees, rather than tree taxonomic diversity, for sustaining the diverse arboreal fauna in tropical forests.
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The algae of water basins i Novohradské hory
PLOCOVÁ, Alena
This thesis deals with six ponds, artificial snall lakes, (Mlýnský, Huťský, Pohořský, Uhlišťský rybník, Zlatá Ktiš a Kapelung) in the Novohradské mountains. They were studied at the interval of years 2004-2006. The basic hydrochemistries and variety of species of planktonic Algae and Cyanobacteria were analysed there. The volume of NH4-N was the highest in Mlýnský pond (20-76 ?g/l), which proves for a recent organic pollution. In other cases the rate was in range of 13-53 ?g/l. The most of NO2-N was again found in Mlýnský pond where its rate reached up to 420 ?g/l. The total amount of t-P was of the same rate in all the sites. It differed only slightly- 58-91 ?g/l. From the hydrochemical data follows that the most nutrients loaded is Mlýnský pond and the cleanest is Pohořský one The transparency (Seccki depth) of all the localities is also high (76-200 cm). It can be compared to the lakes of the Bavarian Forrest and the Bohemia Forest (Šumava). The proportion of N/P is usually between 7,0-29,8 (Chart 11), which shows evidence of limiting P (the most common limiting factor for phytoplankton in fresh waters). The total amount of found taxa (98) is comparable to e.g. lakes of the Bohemia Forest (260), this ara is however more explored. The largest amount of species is at Huťský pond (38) and the smallest one is at Uhlišťský pond (17). As a new species for the the Czech Republik was found Staurastrum arctiscon and Phaeospaera gelatinosa, than another interesting discovery is Vacuolaria penardii and Chloromonas nivalis (Scotiella nivalis). Also Dicranochaete sp. and Paulinella chromatophora are noticeable. The ponds of the Novohradské mountains are from the point ob view of hydrochemistry view unigue habitats. They make for refugium oligotrophic, rare and interesting species of Cyanobacteria and Algea and that is why they deserve proper protection.
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