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Drivers of ectomycorrhizal fungal species richness on large spatial scales
Petr, Andrej ; Kohout, Petr (advisor) ; Šímová, Irena (referee)
Ectomycorrhizal (EcM) fungi form mutualistic relationships with some woody gymnosperms and angiosperms that play an important role in the functioning of most terrestrial ecosystems. Using enzymes capable of sequestering nitrogen and phosphorus from complex organic compounds, EcM fungi make these elements available to their host plants, which in turn provide them with the carbon compounds on which EcM fungi are vitally dependent. However, different species of EcM fungi differ from each other in their ability to sequester nitrogen and phosphorus from organic compounds, as well as in their carbon requirements from plants. The importance of the EcM symbiosis for the ecosystem therefore depends on the species richness of the EcM fungi, which is influenced at large spatial scales by a number of interacting factors, in particular the density and diversity of host plants, climate and soil properties. As EcM fungi generally exhibit low host preference, the density of host vegetation and the associated higher nutrient availability for EcM fungi has a greater influence on their species richness on a global scale than the phylogenetic diversity of host plants. In addition to these environmental factors, however, the distribution of EcM fungi is strongly related to their biogeographic history. In the context of...
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Is CO2 fertilization responsible for plant growth enhancement across different biomes?
Pyšek, Ivan ; Šímová, Irena (advisor) ; Lhotáková, Zuzana (referee)
Production of plant biomass depends on abiotic and biotic factors, these factors vary across biomes. Concentration of carbon dioxide in the atmosphere is one of the abiotic factors. The effect of this factor on plant is intensively studied. Current climate changes includes global warming, that is influenced mainly by anthropogenic activity (burning fossil fuels and the consequent increase in the concentration of greenhouse gases: carbon dioxide, methane etc.). Due to the increased concentration of carbon dioxide in the atmosphere, plants likely increase their growth, photosynthetic activity, decrease their stomatal conductance and the rate of transpiration. Increasing concentration of CO2 can thus have a positive impact on plants. The FACE method monitores plant reactions to enhanced concentrations of carbon dioxide in the atmosphere in natural environment. The response of plants to increasing concentration of carbon dioxide is influenced by biotic and abiotic factors, which vary across biomes, and also by the type of plant metabolism (C3 and C4 metabolism). Plants with C3 metabolism react to increased concentrations of carbon dioxide immediately, but this response is diminished as they acclimatize over the years. In contrast, plants with C4 metabolism react with a delay, but there is not such a...
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Usefulness of habitat suitability models in research of orchid spatial distribution
Linyucheva, Anastasia ; Kindlmann, Pavel (advisor) ; Šímová, Irena (referee)
The subject of this thesis is to summarise information about use of the habitat suitability models with a focus on orchids modelling. Habitat suitability modelling is used to study the relationship between the occurrence of the species and the environmental factors of its habitat. Modelling orchid species is especially useful for modelling of rare and endangered species, it can accurately predict the occurrence of different species under future climatic conditions and in non-native localities. Appearance of mycorrhizal symbiotic fungi is a specific factor affecting distribution of most orchids, but it is very problematic to include it in modelling. Also, there is an uncertainty about an impact of this factor on orchid distribution. Results of different modelling methods are sometimes controversial, this issue is studied, but there are no such studies in orchids modelling. Keywords: Orchids, spatial distribution, models, distribution, prediction
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Role of forest in water regime and local climate
Vaníčková, Lucie ; Pokorný, Jan (advisor) ; Šímová, Irena (referee)
Nowadays human society is dealing with comparatively essential problems, such as lack of water and chmate changes. Forests are able to use a great amount of solar radiation efficiently to change liquid water to water steam alongside climate cooling down. Scientists Makarieva and Gorshkov made up a theory which claims that forests are also generators of air humidity. The process is absolutely necessary for replenshing fresh water on land. This theory is based on gradient of pressures among different places. Air flows from places with lover evaporation and higher pressure (ocean) to locations with higher evaporation and lower pressure (forest). In this thesis are described basic mechanisms of theory of biotic pump. Simultaneously there are stated several examples of deforestation, which resulted in significant reduction of precipitation in that area and reduction of accessibility of water for human society. There are also mentioned several examples of attempt to revitalize desertificated area, where the effort is to make cultural landscape to imitate natural vegetation. These projects are primary based on retaining rainwater.
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Relationship between species diversity, temperature and productivity for native and non-native plant species
Szostoková, Kateřina ; Šímová, Irena (advisor) ; Hejda, Martin (referee)
Latitudinal gradient of diversity is typically being explained by the three main hypotheses: The Resources Limitation Hypothesis, The Speciation Rate Hypothesis and The Niche Conservatism Hypothesis. In my study I tested basic assumptions of these hypotheses using native and non-native vascular plants obtained from the new database GloNAF (Global Naturalized Alien Flora). I tested an effect of precipitation, NPP, temperature and historical velocity (difference in temperature and precipitation between the Last Glacial Maximum and present) on species richness. Given that the distribution of non-native species is among continents irregular (we can divide them into two groups - Australia with Europe and North America and South America with Africa and Asia), I tested the abovementioned relationships at both - global and continental scale. Species richness of native species increased with NPP, precipitation and temperature and decreased with the difference in temperature. The global distribution of non-native plants increased with precipitation and temperature velocity and decreases with temperature and precipitation velocity, although the results varied for particular continents. Unlike other studies the number of non-native species didn't correlate with the number of native plant species. Concurrently...
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Substrate specifity of epiphytic communities of diatoms (Bacillariophyceae) and desmids (Desmidiales)
Mutinová, Petra ; Neustupa, Jiří (advisor) ; Šímová, Irena (referee)
Substrate specificity of epiphytic communities of diatoms (Bacillariophyceae) and desmids (Desmidiales) Bc. Petra Mutinová Master's thesis, Prague, 2015 Abstract It has been always assumed, and frequently reported, that host plants, as biologically active substrates, should have a direct influence on associated epiphyton. However, some studies favoured the neutral substrate hypothesis. Thus the relationship between host plant and epiphytic community remained unresolved. This Master's thesis focused on the basal question that numerous previous studies overlooked. Is there any significant influence of host plant on freshwater algal epiphyton in comparison to the influence of other factors, e.g. site and environmental conditions? In addition, substrate specificity of individual algal taxa was investigated. The research concerned several types of natural plant substrates at several water bodies in the Czech Republic, which provided a more accurate and general insight in the ecology of microphytobenthos. The results have demonstrated that site was the main factor affecting epiphytic community structure, followed by mild, but still noticeable, effect of environmental conditions (pH and conductivity). In contrary, host plant had almost no influence and very few algal species were found to be host specific....
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Limitation of species richness
Szostoková, Kateřina ; Storch, David (advisor) ; Šímová, Irena (referee)
Currently we can find two main hypotheses of diversity dynamics in time in literature - bounded and unbounded hypothesis. According to bounded hypothesis diversity is limited, while unbounded hypothesis says that there are no obvious limitations of diversity. Evidence for these main hypotheses comes mainly from paleontological research, studies of phylogeny and comparison of local and regional diversity. None of these approaches give us clear and incontrovertible evidence of diversity limits. The aim of this work is to show some evidence that confirm (or not) limitation of diversity in mentioned kinds of biological research. Also, I would like to point out some critics and imperfections of used methods.
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Relationship between functional and species diversity of birds in South Africa
Džamba, Roman ; Hořák, David (advisor) ; Šímová, Irena (referee)
Species distribution and composition of bird communities of South Africa is not accidental, but is influenced by environmental conditions, habitat structure, and natural history of the area. Functional traits of the species (morphology, dietary strategies or reproductive parameters) give information on how the individuals interact with the environment they live in. The description of the functional characteristics, expose specific adaptations and the role of the species in the studied ecosystem. On the basis of functional characteristics we are able to estimate functional diversity of studied community. The spatial variability of species and functional diversity allocates longitudinal gradient. Regarding the morphological and reproductive parameters that are continuous in nature and more species- specific, we observe a faster increase in functional diversity. Considering the feeding preferences that are categorical and show a limited number of levels, a modest increase in functional diversity apparent is. Dietary functional diversity is more evenly distributed. Relationship between the functional and species diversity can provide us with information about how species are added to the community or answer the question to what extent the higher number of species requires more ecological space. The...
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