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Factors affecting population dynamics of endangered plant species Dianthus arenarius subsp. bohemicus
Sejrková, Petra ; Dostálek, Tomáš (advisor) ; Ekrtová, Ester (referee)
This diploma's thesis deals with critically endangered species Dianthus arenarius subsp. bohemicus from family Caryophyllaceae. Its distribution range is now limited on its last natural locality in National natural monument Kleneč. As a result of the change in land use (especially the abandonment of grazing), there was a significant reduction in its population size at the end of the 20th century and it was close to extinction. That is why action plan for species conservation was approved, which included number of management interventions at the locality. The most important was the removal of the upper humus horizon, which aims to create free gaps in the sand that allow the emergence and growth of new plants of D. arenarius subsp. bohemicus. The study species is also attacked by herbivores and it was predicted that increasing population might be endangered with increased herbivore population. The aim of this thesis is therefore to describe the population dynamics of the species, to evaluate the effect of the management and to determine how the herbivory affects the population dynamics of the species. The population growth rate decreases over time with vegetation succession. Even eight years after removal the population is still growing. The population growth rate is most affected by change in...
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Mechanisms driving di- and tetraploid coexistence in mixed-ploidy populations of Tripleurospermum inodorum
Nedomová, Anežka ; Čertner, Martin (advisor) ; Dostálek, Tomáš (referee)
Genome duplication plays a significant role in plant evolution. Formation of new polyploids is generally considered to be rare. Nevertheless, under natural conditions mixed-ploidy populations occur in relatively large numbers. Only the observations in the cytotype contact zone can identify all the factors affecting the stability or instability of the population. Number of research focusing on study of cytotype coexistence in natural mixed-ploidy populations is still low. As a model system for the study of mechanisms governing cytotype coexistence was chosen the Tripleurospermum inodorum. Research focused on natural mixed-ploidy populations and also on planted mixed-ploidy populations. Permanent plots were located in south, west, northwest and north Bohemia. Field observations were supplemented by cultivation experiments carried out in the greenhouse. Several phenomena were discovered at the level of whole populations. Cytotype distribution in the plot was random. The spatial structure of natural populations was quickly changing even within a single season. Even between single plot evaluations the cytotype ratios varied. Three percent of all plants were triploid hybrids. Most often detected cytotype in soil seed bank was diploid cytotype. The study of population dynamics shows, that tetraploids are...
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Factors influencing population dynamics of rock outcrop plants
Nováková, Terezie ; Münzbergová, Zuzana (advisor) ; Dostálek, Tomáš (referee)
Because the rock outcrops are inhospitable habitats with unfavorable conditions, rock outcrop plants have evolved special adaptations. Species occurring on such habitats are very often threatened or endemic. It is thus necessary to focus on this group also in terms of its life cycle and population genetics, because the size and evolution of populations and their genetic diversity are important factors for their conservation. For these purposes, we study their population demography. Based on transition matrices we can reveal the future performance of populations. Genetic analysis can help us to reveal the direction and intensity of the gene flow and genetic diversity of populations. This thesis is a literature review summarizing the current knowledge of rock outcrop plant species, their population biology, genetics and other factors influencing it. The second part outlines the research conducted on Aurinia saxatilis subsp. saxatilis and shows the first results of the future diploma thesis.
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Population dynamics of critically endangered species Dianthus arenarius subsp. bohemicus
Sejrková, Petra ; Dostálek, Tomáš (advisor) ; Hemrová, Lucie (referee)
The aim of this thesis is review studies on population dynamics of rare plant species considering regulation factors responsible for changes in population dynamics. It also includes usage of matrix models as a tool of demographic analysis. This information allows us to identify not only trends in population development, but it can help us to understand factors responsible for these changes as well. We also find out which part of the life cycle should be the target of conservation action. Further the thesis should garther information about critically endangered species Dianthus arenarius subsp. bohemicus, its habitat and management. Key words: population dynamics, Dianthus arenarius subsp. bohemicus, life cycle
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Population dynamics of Asp Leuciscus aspius from the Želivka dam
Bouše, Eduard ; Švátora, Miroslav (advisor) ; Pivnička, Karel (referee)
The aim of this study was to evaluate the material about the asp Leuciscus aspius (L., 1758) from the dam Želivka - Švihov in the years 1971 - 2014. Main emphasis was put on the analysis of the flock spawning from 2008 - 2014. Here, basic abiotic conditions were monitored at the time of the spawning and growth and population characteristics were calculated. Spawning took place at two locations, at 4 - 10 0 C, the asp showed a spawning site accuracy. Males predominated on the spawning grounds in the overall ratio of 1,22 : 1. The age of the fish examined ranged from 3+ to 13+. The average mortality of adults is about 0,4. Additional flock spawning ranges from 20 to 50%. The length at which scales begin to form (SL = 29,7 mm), was determined by using the rate between the body length and scale radius. Differences in the growth rates between males a females are minimal, only from the third to the fifth age group, males showed a higher growth rates. The length - weight relationship can be described as W = 0,0153. L3,19 .
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Population dynamics of Red-crested Pochard (Netta rufina)
Poláková, Klára ; Musil, Petr (advisor) ; Storch, David (referee)
This study is aimed at analysis of long-term and short-term changes in numbers of Red-crested Pochard (Netta rufina) in Třeboň region. This species is increasing in long-term period and it is also spreading into new localities in the Czech Republic. There were recorded two waves of arrival of Red-crested Pochard arrive, i.e. in April and in May. The total numbers were decreasing at the end of breeding season (from the beginning of July) in study area. The water surface area and area of littoral vegetation were found to be the most important factors affecting preference of individual ponds in pre-breeding season. Furthermore, water transparency seems to be important factor affecting numbers of broods, ducklings and adults in post-breeding season. Low numbers of broods per 1 female were recorded in years with high numbers of Red- crested Pochard at the start of breeding season. However, the frequency of brood parasitism was higher in these years. Key words: Netta rufina, Red-crested Pochard, population dynamics, ducks, breeding, numbers, brood parasitism, south Bohemia
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Population dynamics of Asp Leuciscus aspius ( L., 1758) from the Želivka dam
Bouše, Eduard ; Švátora, Miroslav (advisor) ; Pivnička, Karel (referee)
The scale material of the asp (Leuciscus aspius, L., 1758) collected from the Želivka dam between 1971 and 2012 has been processed and evaluated. The samples gathered between 2008 and 2012 have been used to determine the basic growth and population characteristics. In the first place I focused on the shoal spawning analysis. The age of individuals in this analysis ranged between 3+ to 13+, at the body length ranging between 370 to 690 mm. The length of the fish when the scales begin to appear (SL = 29,7 mm) was determined on the base of correlation between the body length and the scale radius. The growth rate in recent years was defined using the technique of back - calculation from the scales. The body length-weight relationship can be described as W = 0,009 ∙ L3,1 . The difference in the growth speed between males and females was minimal and statistically inconclusive. The growth speed of an asp in the Želivka dam is roughly at the same level as all other water reservoirs in Czech Republic.
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Supplementations of the Mallard and their impact on wild populations
Pechmanová, Hana ; Musil, Petr (advisor) ; Kreisinger, Jakub (referee)
The Mallard (Anas platyrhynchos) is quite a popular game bird species. In many states, particularly in Europe and North America, captive-rearing and releasing of mallards has become common practice in wildlife management. The aim of these supplementations is to boost the size of hunted populations. More than three million Mallards are released each year. This paper aims to summarize and assess the potential effects of captivity-reared Mallards on the wild populations. Supplementations of mallards pose a threat to the genetic identity and variability of wild populations and may potentially lead to morphological and behavioral changes. Breeding facilities can be source of many pathogens, so supplementations may lead to transmission of these pathogens into wild populations. All the factors mentioned above may thus affect the fitness and population dynamics of wild Mallards. This paper also briefly considers how the releases can affect other species and the environment. This issue is not well studied so more studies and appropriate monitoring are needed for an assessment of the rate of these processes.
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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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Effect of grazing and mowing on vegetation of dry grasslands
Pechová, Tereza ; Münzbergová, Zuzana (advisor) ; Čiháková, Kateřina (referee)
Grassland communities are natural part of our landscape. They were mostly created or maintained by human. If we leave them to their natural development they will disappear. Today grazing or mowing is recommended as an appropriate management. This work is an answer to the beginning of the grazing and mowing management in NPP Kaňk near Kutná Hora. Its goal is preparation for the monitoring of grazing and mowing, which will be in progress in this locality since year 2010.
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