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Seasonality in reproduction and abundance of birds in African savannas
Kučminová, Veronika ; Hořák, David (advisor) ; Remeš, Vladimír (referee)
Seasonality of climate is a crucial factor that determines the existence of African savannas. Especially, the rainfall seasonality is a key factor in the abundance and reproduction of bird species of the savannas. Precipitation determines the timing of reproduction directly, but mainly indirectly through the influence of the environment, phenology, and productivity of plants. The vegetation determines the availability of resources and shelters. However, the widespread distribution of the savannas across the continent means that the seasonality and consequently the environment varies considerably from one area to another due to the different timing, size, and duration of wet and dry seasons. Breeding, as well as the abundance of savanna birds, is clearly influenced by the availability of food, which is determined by seasonal rainfall. For most species, the rainy season is an ideal time for reproduction, but there are also other groups of birds, that prefer a dry season for breeding and nesting. The birds must cope with unfavourable conditions outside the breeding season or leave their breeding areas. The abundance of birds in savannas is also significantly affected by the presence of palearctic migrants. Migration is therefore an important factor of the seasonal abundance of the savanna avifauna....
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How do bird species richness and abundance differ between military training areas and surrounding landscape? A case study from the Hradiště military area
Bušek, Ondřej ; Reif, Jiří (advisor) ; Koleček, Jaroslav (referee)
Since the beginning of the 20th century human land use changed drastically in Central Europe. These changes included: homogenization of the landscape mosaic, intensification of agriculture, urbanization and land abandonment. In turn, these changes affected bird species and perhaps most significantly manifested in population decline of open habitat birds. Therefore, it is important to investigate sites, which were not affected by the changes mentioned above, such as military training areas (MTAs) - places dedicated to training of armed forces. Previous studies have shown that MTAs seem to host remarkably high bird diversity and abundant populations of bird species of conservation concern. This may be caused by two major factors. First, closure of MTAs to all human activies besides military training spared them of the landscape changes mentioned above. Second, the military training itself produces a very heterogeneous habitat mosaic that allows coexistence of many species with different ecological requirements. To my knowledge, no study compared bird assemblages between MTAs and surrounding landscape directly. At the same time, such data are crucial to assess the value of MTAs for bird conservation reliably and, as a consequence, they enable to think more deeply about mechanism generating this value....
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Abundance of and threats to the snow leopard in various regions of its occurrence
Valentová, Kamila ; Kindlmann, Pavel (advisor) ; Hulva, Pavel (referee)
Snow leopard (Panthera uncia) is an endangered species and its population size is steadily declining. This thesis attempts to introduce and analyse the main factors threating its survival with reference to each country of its occurrence: China, Bhutan, Nepal, Pakistan, Afghanistan, Tajikistan, Uzbekistan, Kyrgyzstan, Kazakhstan, Russia and Mongolia. To conserve the remaining snow leopard populations, it is necessary to detect its distribution in various areas. Here, recent data about its worldwide distribution are presented. Snow leopard has a very secretive lifestyle, which makes estimation of its abundance quite difficult. Therefore, I also present here an overview of methods, such as sign survey, capture-recapture, predator:prey biomass ratios, photo-capture rate and genetic analyses, used for estimation of abundance of snow leopard with reference to conducted studies. I discuss their advantages and disadvantages under different conditions. Key words: snow leopard, abundance, threats, worldwide distribution, conservation
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The relationships between diversity patterns and community abundance
Dlouhá, Hana ; Storch, David (advisor) ; Keil, Petr (referee)
Increase in the number of species with area is one of the most studied ecological patterns. There is a considerable amount of literature devoted to this question. The rate of increase in the species diversity with area isn't equal at all the spatial scales, as shown by empirical studies. On the finest and coarsest scales, there is distinctively higher rate of increase than on the middle (regional) scales. These distinctions were attributed to many characteristics of environment, taxon etc. There is a possibility to explain the variability of this particular rate by mean species abundance. This work focuses on summarizing the relationships between the rate of increase in biodiversity with area, factors that influence it and mean species abundance.
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Atmospheric characteristics of white dwarfs
Krejčová, Kateřina ; Kawka, Adéla (advisor) ; Mayer, Pavel (referee)
We have analyzed the ultraviolet spectra of 40 hydrogen-rich (DA) white dwarfs. These spectra have been obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite and are publicly available via the MAST FUSE database. We derived the effective temperature and surface gravity by fitting the hydrogen Lyman spectral lines with model spectra. By applying white dwarf evolutionary models, we were able to determine the white dwarf mass, cooling age and absolute magnitude. These then allowed us to determine the distance to each star and its predicted gravitational redshift. We have identified several chemical elements in the white dwarf spectra. We determined the abundances of C, Si, P and S by measuring the equivalent widths of selected lines of these elements. Finally, we studied the spectra of J0623-376 and LM Com in more detail.
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More-individuals hypothesis
Bohdalková, Eliška ; Storch, David (advisor) ; Sedláček, Ondřej (referee)
Gradients in species richness are often explained by variation in energy availability. Positive relationship between energy and number of species may be caused by many mechanisms. One of them is the 'more individuals' hypothesis (MIH). According to it greater energy availability enable more individuals to coexist and more individuals can be divided into more species with viable populations. However, authors do vary in exact formulation of the MIH and so they vary in predictions that they test. Review of literature has also revealed that studies are fundamentally different in the approach to testing MIH. Some studies examine whether mechanism of MIH can operate in real assemblages and they often give a positive answer. Other studies ask whether MIH is able to explain spatial patterns of species richness. The answer is mostly negative. Number of species is often closely related to energy without the mediating effect of the number of individuals. There is also the question whether the number of individuals really determines number of species, and not vice versa. However, these two variables are certainly linked. Therefore, regardless of the causality, the relationship between the number of individuals and number of species is worth exploring.
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Feral Pigeon (Columba livia f. domestica) Census in Selected Sites of Prague
Bukačová, Kateřina ; Řezníček, Jan (advisor) ; Štěpán, Jiří (referee)
This thesis deals with the monitoring of numerous rate of domestic pigeon (Columba livia f. Domestica, hereinafter referred to as pigeon) in a given area and its spatial activity. The work includes incidence monitoring of individual pigeons depending on daytime and weather. The monitoring was carried out by observational method in the period from February to May 2015. The observations were related to individuals who occurred the monitored area (the buildings in Dukelských hrdinů street). Furthermore, the work compares the results from population census of Prague pigeon and the results from census of other European cities. It was further investigated whether the amount of pigeons in the area is affected by abiotic conditions (air temperature and weather). The result of the thesis should contribute to better knowledge of overall pigeon rate determining in the capital city of Prague. The collected data may help to gain a deeper knowledge of the entire population ecology living in this territory. They can also be beneficial, for example, in reducing of the pigeon numbers or serve in other investigations. Key words: pigeon, Domestic Pigeons (Columba livia f. domestica), abundance, monitoring, abiotic conditions, population
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Diversity and biogeography of protists
Ryšánek, David ; Škaloud, Pavel (advisor) ; Kulichová, Jana (referee)
My bachelor thesis consists of two parts. The first part is a literature review, the second part is a practical one, which contains the results of my own research. The first part of my thesis is devoted to the literature review, dealing with two current views on biodiversity and biogeography of protists. The first theory, model of protist ubiquity is described in a few points and illustrated by several examples. Likewise is presented the second hypothesis of moderate endemicity model. In conclusion, both models are compared and advantages and disadvantages of each theory are pointed out. In the second part of this thesis I briefly describe the genus Klebsormidium, which is followed by an optimization of molecular methods to study biodiversity and biogeography of this genus.
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Telemetric monitoring of the feral pigeon ( Columba livia f. domestica) population at the Karlovo namesti square in Prague
Kanov, Štěpán ; Řezníček, Jan (advisor) ; Novák, Jindřich (referee)
"A Telemetric monitoring of the feral pigeon ( Columba livia f. domestica) population at the Karlovo náměstí square in Prague" This thesis deals with both the monitoring of numbers in the pigeon (Columba livia f. domestica, "the Pigeon") sites in question and also the spatial definition of the daily activities of individual specimens using a telemetric system. Previous researches gathered data on population density and food routes usually obtained by observation. Therefore we believe it's important to supplement this data with spatial movement maps of individuals that cannot be obtained by observation but the telemetry system allows us to do so in certain time period. The data obtained from GPS trackers will be processed into daily spatial activity maps of the specimen. These data will hopefully help us to gain insight into the life of not just specific individuals, but will also allow us to derive spatial activity of the entire population living in the locality in question. The results will be compared with the results from the previous pigeon count. This knowledge can be useful to population control, or serve in other studies. Keywords: pigeon, abundance, telemetry
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