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Distribution of population sizes within different orchid metapopulations
Švecová, Magdaléna ; Kindlmann, Pavel (advisor) ; Štípková, Zuzana (referee)
Orchids, as one of the most species-rich families in the world, are known for their specific symbiotic relationships with other organisms and can therefore be referred to as indicators of the state of vegetation. Studying orchids as metapopulations allows us to better estimate the level of threat of individual orchid species. The traditional metapopulation model assumes a metapopulation consisting of sub-populations, where individual populations are connected by migration, and colonization of new and recolonization of existing localities occurs. Orchids, on the other hand, show a different behavior. Their seeds are spread passively by wind, and the colonization of new habitats is therefore rather random. Therefore, a new model would be suitable for the study of orchids, which should include information on the size of the population of a given orchid species, taking into account the region in which they occur. The metapopulation is also influenced by the temperature and amount of precipitation before the flowering period, the possibility of individual sterility or dormancy, and last but not least, the quality of management on the site. These variables should be included in a new metapopulation model that could better describe changes in orchid metapopulations. This thesis provides the basis for a...
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Small mammals communitis in the surrounding of town České Budějovice and the common voles (Microtus arvalis) population ecology
KAPOUN, Ondřej
The changes in the small mammals abundance were studied on the total of eight plots in three different habitats situated on three different localities during the period between autum 2004 {--} spring 2006. The effects on small mammals comunities composition were odserved.Also the effect of locality, habitat type, vegetation structure and avian predation on vole numbers and reproduction parameters was assessed. The impact of habitat type on population dynamic was also examined. The highst numbers of small mammals species and the highst species diversity were found on the set-aside-plots. This may be explained by species-specific relationship to vegetation structure and also probably heterogenity of vegetation cover. The predation by Common Kestrel (Falco tinnunculus) and Common Buzzard (Buteo buteo) had no significant effect on vole numbers. In addition, no differences were found in population dynamics between localities. However, there were some differences between habitat types: the trefoil-fields serve as source patches of individuals in breeding season (63.08% of sexually active voles; mean fecundity 3.6 juv./female) while set-aside-plots are probably sinks (47.16% of sexually active voles; mean fecundity 1.3 juv./female). This may be explained by food quality. Set-aside-plots seem to have an important role on the overwintering of individuals, as in the rest of the habitats local population could become extinct during winter. This might be due to some protective influence of plant biomass, with restrain the impact of the winter season on vole survival. The role of habitat types (sink/source) is changing during season. Neverthelles, "trefoil-field" patches, influence magnitude of vole number fluctuations while set-aside-plots are important for maintenace and stability of vole metapopulation. The bachelor thesis includes a literary review, containing a a brief description of several basic hypotheses offering explanation of the causes and the maintenance of the population cycles. Another section of the review concerns variation in small mammal population dynamics on the geographical and local level. Some attention is also paid to changes in the small mammal demographics in the course of a population cycle.
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Ecology of flower smuts (Microbotryum) and their hosts from family Caryophyllaceae
Koupilová, Klára ; Koubek, Tomáš (advisor) ; Marková, Jaroslava (referee)
Anther-smut fungus (Microbotryum spp.) infecting plants of the Caryophyllaceae represents one of the most extensively studied plant pathogen systems. Anther-smut is a pollinator-borne disease that turns infected plants completely sterile. The aim of this thesis is to sum up the main findings about ecology and epidemiology of anther-smut disease and it mainly deals with various factors that influence disease spread and occurrence in nature. According to existing research, abiotic factors play minor role compared to biotic factors and interactions. Among the most pronounced, we can find variability in pathogen virulence and host resistance and also vector behaviour. When studying epidemiology of Microbotryum spp., it is necessary to take account of spatial population structure and metapopulation dynamics as well. Comparing life histories of different host species can also bring useful information. Key words: anther-smut, Microbotryum, Caryophyllaceae, pollinators, resistance, epidemiology, metapopulation dynamics.
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Ecology of flower smuts (Microbotryum) and their hosts from family Caryophyllaceae
Koupilová, Klára ; Koubek, Tomáš (advisor) ; Marková, Jaroslava (referee)
Anther-smut fungus (Microbotryum spp.) infecting plants of the Caryophyllaceae represents one of the most extensively studied plant pathogen systems. Anther-smut is a pollinator-borne disease that turns infected plants completely sterile. The aim of this thesis is to sum up the main findings about ecology and epidemiology of anther-smut disease and it mainly deals with various factors that influence disease spread and occurrence in nature. According to existing research, abiotic factors play minor role compared to biotic factors and interactions. Among the most pronounced, we can find variability in pathogen virulence and host resistance and also vector behaviour. When studying epidemiology of Microbotryum spp., it is necessary to take account of spatial population structure and metapopulation dynamics as well. Comparing life histories of different host species can also bring useful information. Key words: anther-smut, Microbotryum, Caryophyllaceae, pollinators, resistance, epidemiology, metapopulation dynamics.
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Dynamics of rare and threatened species on local and regional scale- from theory to practice
Lampei Bucharová, Anna ; Münzbergová, Zuzana (advisor) ; Tichý, Lubomír (referee) ; Jiménez, Ares (referee)
To assess the status of a rare plant species, we must first understand the factors that affect the size of populations and their numbers. In this thesis, I study processes affecting plant species prosperity on local scale (paper 1), factors influencing species distribution in landscape and ability of species to colonize new habitats (paper 2) and species traits responsible for gene flow between established populations (paper 3). Since I work with rare plants, I also aim to turn theoretical knowledge into practical recommendations for nature conservation (paper 4) to help effectively preserve rare and endangered species. In the first 3 papers, I work with two rare fern species restricted to serpentine rocks, Asplenium adulterinum and A. cuneifolium, in a study system covering 10 × 10 km. I found that both species are long living (several decades) and in the study region, populations are in a good state and slowly growing. Even very small populations (10 individuals) have quite high chance to survive. In both fern species, I found dispersal limitation, which might be surprising regarding huge production of small spores in ferns (paper 2). The species differ in ploidy and thus, also mating system. A. adulterinum is tetraploid and its main breeding system is intragametophytic selfing. A. cuneifolium is...
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