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Trenchless Technologies of Communication Building
Hanzelka, Jan ; Malášek, Jiří (referee) ; Kašpárek, Jaroslav (advisor)
The target of submitted work was to sum up a view of current methods and the machines for the building of communications by trenchless technologies and to conduct a critical analysis each technologies parallely. Trenchless technology are fascinating and interesting method, but also are hardest imposition for structural engineer, based on knowledges, namely not only from geology, geomechanics, static and staunch, but also mechanical technology and engineering constructions. Builders of tunnels coins shaft and entrances to the country over mountains and below waterways so, to go traffic road and gas main fabricate. In those work were to be circumscribed basic method construction communication namely how verbally, so and with the aid of apposite picture. Resulting list of firms describes instantaneous offer in the marketplace with those machine.
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Species-area relationship in birds: variation across temperate zone environments
Gaigr, Matěj ; Hořák, David (advisor) ; Hanzelka, Jan (referee)
The relationship between area and number of species is one of the oldest and most studied principles in ecology, often referred to as one of the laws of ecology. Ecologists use it primarily to model the expected number of species in a given area. The Species-Area Relationship (SAR) states that the larger the area being, the greater the number of species present. However, area is not the only factor influencing species diversity - habitat heterogeneity is also a frequently studied factor affecting species richness. The number of species in an area tends to be positively influenced by heterogeneity since factors that are positively correlated with heterogeneity have a large influence. These factors include the species diversity of vegetation, the level of energy productivity, the number of microhabitats, the effect of disturbance or the amount of different food sources. Individual temperate habitats differ in the relative contribution of heterogeneity in its impact on observed species abundance. Species abundance is not only influenced by habitat heterogeneity, but also by other factors such as altitude, climate or latitude. The most affected habitats regarding the relative contribution of heterogenity are forest environments. Vertical diversity is the main influence causing high heterogeneity in...
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Factors influencing the ecological stability of the Novozamecky rybnik Reserve
Hanzelka, Jan ; Čihař, Martin (advisor) ; Reif, Jiří (referee)
Fishponds and their surroundings are affected by many factors disrupting their ecological stability. In this thesis, influences of selected factors are evaluated. Particularly it is discussed excessive overgrowing of shoreline by plants, pond siltation by allochthonous material from catchment area, eutrophication process and intensive fish farming. It is presented the impact of these factors on local avifauna in Novozámecký fishpond National Nature Reserve and Special Protection Area and compared with Třeboňsko Special Protection Area. Birds use the ponds especially as nesting habitat and food source. Therefore, it is necessary to describe the influences disrupting this habitat. The frugal interference with mentioned processes is needed in terms of dynamics of the ecological stability. Thereby the requested fishpond parameters and ecological and economic values will be maintained. Fisheries management and lack of historical management in the form of reasonably performing mowing and grazing in the vicinity of the ponds has the greatest impact on the habitat of birds upon Třeboň fishponds. Novozámecký pond also suffers from the lack of historical management, but the unsatisfactory state of the pond is rather due to the overall eutrophication of the environment.
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Intraspecific variability in population trends of farmland birds: influence of habitat and altitude
Hanzelka, Jan ; Reif, Jiří (advisor) ; Šálek, Miroslav (referee)
Farmland bird populations in Europe have been in decline for a long time. Agricultural intensification and growing a large share of crops that provide suboptimal breeding habitat could be the main causes of the observed decline. To explore these possible drivers, I focused on population trends of farmland bird species in different habitats in the Czech Republic over the periods 1982-1990 and 1990-2010. Specifically, I focused on the variability in trends within each species in respect to the differences in landscape management between the lowlands and mid-altitude areas before and after 1990. The expected effect of intensive farming in the lowlands until 1990 was reflected by a strong decline in populations of Northern Lapwing and Yellowhammer. The influence of less intensive farming in mid-altitude areas causing moderate population decline was confirmed rather by shrubs and trees species than farmland specialists. After 1990, less intensive farming in the lowlands should reduce the decline, which may have occurred, but compelling comparison of population trends between the two time periods was not possible for most species due to the lack of data. On the contrary, more intensive population decline in mid-altitudes after 1990, which should be the response to arable land abandonment, was not...
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Bird abundances and the height of vegetation
Černohorská, Eliška ; Hořák, David (advisor) ; Hanzelka, Jan (referee)
Bird abundance, it means the number of individuals at a specific site relates to the number of species in the area. It is common that species-richer habitats contain more individuals. Bird abundance which detected most frequently during the breeding period is influenced by the vertical structure of the vegetation so that habitats with low vegetation (e.g. grasslands) occupy smaller numbers of birds than the cover of higher vegetation (e.g. shrublands and forests). Most often total bird abundance positively correlates with increasing vegetation height determined by successional stages. Based at the stated studies, it is evident that bird species respond to vegetation height and its changes in a specific way, therefore it is difficult to make general conclusions. Negative correlation between vegetation height and bird abundance observed in some studies can be caused by various methods of data collection on vegetation height in different areas. In my opinion, bird abundance relates more to vegetation density and vegetation stratification than to vegetation height. The reason is that bird occurrence in forest habitats is impacted by well-developed undergrowth not just by forest canopy height. To further clarify how vegetation height affects bird abundance, we need more research that would compare bird...
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The impact of invasive plants on bird communities
Neubergová, Kristýna ; Reif, Jiří (advisor) ; Hanzelka, Jan (referee)
Invasive plants are among the major factors participating on the threat to biodiverzity. Birds are one of the Gross of organism endangered by this factor. However, birds provide a variety of ecological services and are often used as indicators of the state of enviroment in broker scale of landscape. Several researches assessing impal of invasive plants on ecosystem biodiverzity have been done, but none of them targeted bird communities specifically. Objective of this paper will be to anter free question regarding: (i) comparison of impacts of invasive woody plants and plants; (ii) comparison of impacts by type of enviroment in which the inavasive plant expanded (forest, grasses, island, wetlands); (iii) geographical area sof invasion. (i) The results indicie that from the perspective of bird communities, the negative impact of woody plants and plants was basically identical (76% for woody plants, 74% for plants). (ii) Comparison of impacts by type of enviroment in which the invasive plant expanded proved that the most severe negative impal of invasive plants was in islands biomes (100%), wetlands (91%), grassy biomes (87%). The lest severe impal was in forest biomes (63%). The results for island biomes was quite expected, as this biome is the most susceptible to disbalance of ecosystem. (iii)...
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Bird communities in stands of non-native trees
Hanzelka, Jan ; Reif, Jiří (advisor) ; Hořák, David (referee) ; Šálek, Miroslav (referee)
6 Abstract This thesis deals with the effects of non-native tree stands on birds in the Czech Republic. Non-native plants, including trees, are known to adversely affect the biodiversity. At the same time, birds represent a widely used biodiversity indicator. The studies of bird communities in stands of non-native trees presented here show the extent to which the birds have been impacted by non-native tree stands. This knowledge can be used to evaluate the importance of non-native plants as a biodiversity threatening factor. As the representatives of widespread non-native trees, the broad-leaved black locust and coniferous black pine were selected. In these stands I investigated possible mechanisms affecting bird communities, arising from assumed differences in vegetation structure, bird species richness, bird community composition, food supplies, and nest predation pressure compared to the stands of native oak and native Scots pine. In general, the bird species richness positively correlates with the vegetation structure complexity. Despite the fact that the non-native stands proved to have a higher heterogeneity of vegetation structure than the native stands, bird species richness did not differ among the focal stands. The bird community composition was primarily affected by the birds' preference of...
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Birds in vegetation of invasive allien plant species
Kroftová, Magdalena ; Reif, Jiří (advisor) ; Hanzelka, Jan (referee)
Invasive plant species cause changes in the environment of natural habitat biotopes, and their impact is therefore is probably one of the most important threats to global biodiversity leading to homogenization of local ecological assemblages. Plant invasions disrupt ecosystem stability, change their functioning and structure, cause habitat fragmentation and sometimes function as ecological traps. Many scientists study the impacts of invasive species but they have been focusing mainly on plant communities or invertebrates. Effects on vertebrates, for example on birds, are not sufficiently explored. Birds are important components of ecosystems though, they provide wide range of ecosystem services, regulate abundance of herbivorous insect and some are among the top predators. Birds in turn affect plants by dispersing their seeds but this relationship can sometimes be disrupted by plant invasion. This thesis deals with the impact of invasive plants on bird communities and aims a systematic evaluation and summarization of scientific literature on this topic. Results suggest that birds in invaded ecosystems suffer from higher predation levels, they have lower reproductive success species and diversity of bird communities is reduced. Factors underlying these patterns are a decrease in diversity and abundance of...
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Intraspecific variability in population trends of farmland birds: influence of habitat and altitude
Hanzelka, Jan ; Reif, Jiří (advisor) ; Šálek, Miroslav (referee)
Farmland bird populations in Europe have been in decline for a long time. Agricultural intensification and growing a large share of crops that provide suboptimal breeding habitat could be the main causes of the observed decline. To explore these possible drivers, I focused on population trends of farmland bird species in different habitats in the Czech Republic over the periods 1982-1990 and 1990-2010. Specifically, I focused on the variability in trends within each species in respect to the differences in landscape management between the lowlands and mid-altitude areas before and after 1990. The expected effect of intensive farming in the lowlands until 1990 was reflected by a strong decline in populations of Northern Lapwing and Yellowhammer. The influence of less intensive farming in mid-altitude areas causing moderate population decline was confirmed rather by shrubs and trees species than farmland specialists. After 1990, less intensive farming in the lowlands should reduce the decline, which may have occurred, but compelling comparison of population trends between the two time periods was not possible for most species due to the lack of data. On the contrary, more intensive population decline in mid-altitudes after 1990, which should be the response to arable land abandonment, was not...
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