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Population biology of Dianthus carthusianorum in populations infested by anther-smut
Kasner, Marek ; Koubek, Tomáš (advisor) ; Dostálek, Tomáš (referee)
Anther-smuts (Microbotryum violaceum s. l.) are systemic plant pathogens sterilizing their hosts, thus decreasing its reproduction on the expense of own sporulation. The spores are, consequently, transmitted by pollinator vectors and deposited on healthy flowers. This thesis contributes novel, to date missing information about population-level impact of the pathogen that severely influences its host fitness by examining a relatively new model species Dianthus carthusianorum. Additionally, it considers the effect of pre-dispersal seed predators (caterpillars of Hadena moths). Deterministic matrix models were used for the quantification of the effects of both plant antagonists. Notably, the use of such type of models is rather unique in population biology of plant pathogens. The research was conducted in three localities in Střední Povltaví area in years 2018-2021 when the demographic data were collected, reflecting the whole plant life cycle. During the annual censuses we gathered not only the information about the vital rates of the plants (growth, reproduction, infections...) but also selected size characteristics of permanently marked plants were measured to explore possible changes induced by a systemic infection. The seed recruitment and seedling growth data were provided by seed-addition...
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Population models of plant life-cycles and their modifications by diseases and herbivores
Kasner, Marek ; Koubek, Tomáš (advisor) ; Koupilová, Klára (referee)
Pathogens and herbivores are two important groups of organisms with predominantly negative impact on their plant hosts. Although relationships at the individual level are relatively well understood, the data acquired by those studies cannot be easily translated into effects on the population. Various types of population models, also used in the case of the interactions, give us valuable insight into population dynamics. This bachelor thesis at first describes mechanisms and effects of plant pathogens (with emphasis on pathosystems with anther smut Microbotryum violaceum) and herbivores at the individual and population level for the demonstration of diversity of the systems and to stress the discrepancy between the two hierarchical levels. Furthermore, matrix and integral projection models are introduced as invaluable tools for population dynamics projections and understanding the underlying results of the interactions on plant populations. These models use the entire plant life cycle and require long-term censuses of demographic data. The role of these models in plant-pathogen interactions seems heavily underappreciated, however, and thus there is only a small number of studies with their application. The thesis describes mechanisms of the models, modifications in specific life-cycles and their...
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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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Populační biologie rostlin napadených systémovými parazity
Koubek, Tomáš ; Herben, Tomáš (advisor) ; Šmilauer, Petr (referee) ; Wennström, Anders (referee)
Three separate studies of the effect of plant pathogen on population biology of its host are presented in the thesis. Two are using field data about a widespread system of plant Falcaria vulgaris and its systemic rust fungus Puccinia sii-falcariae. The first study shows, that the disease prevalences in 40 populations of the plant were correlated with the moisture, the soil reaction and the cover of the herb layer at the localities. This was probably a result of the interaction of the life history of the plant and different effect the disease has at various localities. Similar pattern was found in the second study that aimed to determine long-term effect of the disease at the population level at four chosen localities over 4-5 years. Population growth rates were only rarely predicted to be higher for the healthy part of the population when compared with the whole population. Other analyses have however found big differences among years and localities. The locality type (slope vs. field populations) was important factor influencing population stage composition and importance of life cycle transitions for the growth of the population. Finally, the last study explores the possibility that systemic infection in clonal plants might be able to select against clonality. The result of the modelling showed that more...
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