National Repository of Grey Literature 106 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Ecological aesthetics of freshwater wetlands: the importance of environmental heterogeneity and biodiversity
Hájková, Tereza ; Hořák, David (advisor) ; Chobot, Karel (referee)
Ecological aesthetics study landscapes through different interactions of ecological and aesthetical properties of different environments. Ecological aesthetic of wetlands are quite specific, their ecological value can be extremely high, and they bring people many benefits Despite that, wetland ecosystems can be viewed quite negatively. Wetlands support a large number of species, some of which are wetland-dependant species. Wetlands are very variable, and they can have interesting spatial diversity. Environmental heterogeneity encapsulates both these properties of a landscapes, aesthetic, as well as ecological. And that is the reason why it is a crucial aspect of ecological aesthetic.
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...
Synurbanization in wood pigeon (Columba palumbus) and Eurasian magpie (Pica pica)
Tesařík, Jáchym ; Lučan, Radek (advisor) ; Hořák, David (referee)
Both Eurasian magpie and Wood pigeon are typical synanthropic bird species. By studying the available sources, I found that during their synurbanisation, both species have undergone several changes that have facilitated their transition from rural to urban habitats. Due to their adaptability, they have no problems colonizing urban environment and have managed to occupy new and diverse range of nest sites. Thanks to synurbanisation, both Magpie and Wood Pigeon have been able to expand their range and increase their overall abundance. Possibly the biggest threat to urban populations of both species is nest predation, which locally leads to declining population trends and reduced breeding success. Because of predation pressure and the adaptability of both species, I think we can expect not only an increase in abundance and population density in their urban population in the future, but also the occupation of new and more diverse nesting habitats in closer proximity to human settlements.
Semantic segmentation using support vector machine classifier
Pecha, Marek ; Langford, Z. ; Horák, David ; Tran Mills, R.
This paper deals with wildfire identification in the Alaska regions as a semantic segmentation task using support vector machine classifiers. Instead of colour information represented by means of BGR channels, we proceed with a normalized reflectance over 152 days so that such time series is assigned to each pixel. We compare models associated with $\mathcal{l}1$-loss and $\mathcal{l}2$-loss functions and stopping criteria based on a projected gradient and duality gap in the presented benchmarks.
Diversity and abundance of birds in 3D space of Žofínský prales primary forest
Kučerová, Eliška ; Hořák, David (advisor) ; Korňan, Martin (referee)
Bird species are specialized in diverse types of environments. Considering for example forest species, this does not mean that all species inhabit the same ecological niches. Some species occupy undergrowth while others prefer treetops. Some birds are bound to clearings and other gaps in forest cover, and other species require old trees with cavities. Primary Central European mixed forest is not a homogenous environment. But, on small spatial scales, the environment is very heterogeneous. We get an unprecedented variety of habitats especially when including the forest vertical dimension, which birds use much more than it is usually considered in studies. This diploma thesis describes in detail the bird assemblage in the Czech oldest nature reserve NPR Žofínský prales in which vegetation research is currently in progress. However, research dealing with bird mapping in forests still rarely consider the vertical dimension of the environment. Most bird censuses focus on the diversity of species at a site but usually do not include abundance of individual species. I, therefore, focused on a detailed mapping of the bird community on a 50-hectare area in NPR Žofínský prales. During the census, each bird and each bird's exact position in the 3D space of the forest were recorded. Special attention is paid...
The activity of Police of Czech Republic in the South Bohemia in case of finding the booby trap explosive system
HORÁK, David
This diploma thesis deals with the readiness of security forces, especially the patrol service of the Police of the Czech Republic of the South Bohemian Region, which is most likely to be the first to find a suspicious object (eg a booby-trapped explosive system) and must solve the situation so as not to cause life and the health of citizens or property. The thesis defines the basic concepts and characteristics of booby-trapped explosive systems and the procedures for the disposal of these systems.
Bird conservation status along a successional gradient in abandoned military areas
Bystřický, Václav ; Reif, Jiří (advisor) ; Hořák, David (referee)
Populations of open habitat bird species has significantly decreased in the Czech Republic during the last decades due to a number of negative factors, such as urbanization and intensification of agriculture. Due to the deterioration of the quality of these biotopes, a number of bird species (not only those of conservation importance) were forced to look for remaining fragments of favorable habitats, which are, for example, abandoned military training areas. The attractiveness of these territories lies primarily in their former closure for military purposes, which has protected these areas against these negative factors. In addition, army's activities created a heterogeneous landscape characterized by a mosaic of biotopes in different stages of vegetation succession - from bare ground, through grasslands, sparse scrubland, dense scrubland to the forest. However, the significance of abandoned military training areas for birds requires deeper investigation. The main goal of this thesis was to describe conservation importance of bird communities in individual biotopes along the successional gradient, for which a survey of 42 abandoned military training areas was used. The results of my work show that the most declining, endangered and protected species of birds sought out early successional habitats...
Impacts of deforestation of west African mountains on biodiversity
Stříbrská, Eliška ; Hořák, David (advisor) ; Reif, Jiří (referee)
The high rate of deforestation is a global problem with negative impacts on species biodiversity and it also contributes to global and local climate changes. This problem is much more urgent in hotspots of biodiversity and endemism like west African mountains. Moreover, these locations are now recognized as the most fragmented and the most deforested mountains on the African continent. Impacts on local organisms is mostly negative. The organisms are facing habitat loss and the inability to migrate between the isolated regions. The bond between associated animals and plants, that are life depend on each other, is being broken and the whole ecosystem is being changed. In general, the ecosystem is less stable and all these changes make deforestation a chain reaction. Although there are some positive impacts on the biodiversity too, it does not influence the endemic species. It has more positive consequences for the generalist species occupying wide range of habitats and utilizing various food resources. Local communities are also facing the impacts of the ecosystem changes, their lives are negatively influenced by longer and more intensive periods of drought, landslides and they are not able to rely on the supply of the forest products. To be able to change current situation, financial support and...
Evolution of endemism of mountain animal species
Švihálková, Tereza ; Munclinger, Pavel (advisor) ; Hořák, David (referee)
The mountain islands, isolated habitats surrounded by a distinct lowland environment, are home to a variety of endemic animal species. These hot-spots of biodiversity and endemism can be found mainly in tropical areas. Thus, the occurrence of endemics partially corresponds to the general macro-ecological rules of biogeography. For a more specific explanation of the origin and evolution of mountain animal species, we usually proceed from two theories - vicariate and dispersion. The validity of these theories varies in relation to taxon, locality, and evolutionary past, so it is difficult to generalize them globally. This bachelor thesis summarizes the prerequisites for the occurrence of endemic species and knowledge from some world- important mountain localities with a large number of endemic animals.

National Repository of Grey Literature : 106 records found   1 - 10nextend  jump to record:
See also: similar author names
8 HORÁK, David
1 Horák, D.
1 Horák, Dalibor
8 Horák, Daniel
8 Horák, David
2 Horák, Dominik
1 Horák, Dušan
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