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Species diversity of meadows and pastures on small spatial scale
Bartoš, Michael ; Vojta, Jaroslav (advisor) ; Skálová, Hana (referee)
Grazing seems to be not only means of conserving species diversity of grasslands but also - in many cases - of its increasing. This thesis tries to find out the mechanisms of grazing that result in increased or decreased species diversity. The experiment was proceeded in Slupenec, a part of Český Krumlov, where horse pastures are situated. In order to compare grazing and mowing I collected phytosociological data from plots 1 x 1 mš. I also collected data about soil moisture, composition and pH in order to find out the main gradients in vegetation. The vegetation data from plots 20 x 20 cmš were collected before and after grazing on three pasturelands. In the chosen locality, higher level of plant species diversity have been proven on pastures in comparison with meadows. There is significantly higher percentage of plots contributing to the higher level of ß diversity on pastures than on meadows. At the same time the variability of vegetation was in most cases explained by the categorial variable pasture / meadow. Concerning selectivity of grazing, it has been proven that horses prefer grazing on species with greater cover abundance. The plots with lower rate of grazed species have got higher ß diversity. In terms of functional traits of plants, it has been proven that higher percentage of no-rosette...
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Free-ranging herbivores as a dispersal vector for species in abandoned landscape
Lepková, Barbora ; Vojta, Jaroslav (advisor) ; Karlík, Petr (referee)
Endozoochory is an important part of plant-animal relationship. In model area of the Doupov Mountains large herbivore mammals, such as red deer, sika deer and wild boar, act as effective seed dispersers. Out of 282 dung samples 29 719 seedlings of 91 species emerged. The most common species was Urtica dioica (80 % of all seedlings). The amount of seeds in dung as well as species composition were highly dependent on dispersing animal, both showed strong seasonality and differences between two studied localities. Frequency of species in dung did not correspond to their frequency in vegetation suggesting strong preferences of herbivores as predators. However more research is needed to test this hypothesis. Given very high time demands for samples processing beforehand the emergence experiment, the influence of concentration by washing through on seedling emergence and species composition was tested. According to preliminary results more seedlings and species emerge from concentrated samples. However, concentration has no effect on emergence of U. dioica as the most common species. Concentration of samples by running water is recommended for faster emergence in greenhouse conditions. Preliminary results also suggest that the approximation of number of seedlings/species on weight of dry mass is not...
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Modelling of land cover change in abandoned landscape using time series of aerial photography
Brůna, Josef ; Vojta, Jaroslav (advisor) ; Jačková, Kateřina (referee)
Obsah 5 English abstract This thesis deals with modelling of land cover change in abandoned landscape. The study site is located in the military area Hradiště, around the former village Tocov, it is 2,5 km long and 2 km wide. Due to lack of historical vegetation data on landscape scale, historical aerial photographs were used as a primary source of data. They were orthorectified, mosaicked and automatically object oriented then classified in two categories woodland and grassland. Changes between two successive classified images were modelled with generalized linear models with mixed effects (lmer). Variables that were derived from digital elevation model, former land use and spatial variables computed with algorithms based on cellular automata were used. In order to verify the model predictions with the actual situation and for easier interpretation and visualization of results, a new application PEMZOK (Spatially explicit model of overgrowth of abandoned landscape) was developed and is one of the results of this work. Rapid rate of overgrowth of remaining grasslands was found. The largest observed effect on the spread of trees had the distance to the nearest tree or shrub and density of trees in the vicinity (15 m × 15 m) and the wider neighbourhood (105 m × 105 m). Models with these variables and land use...
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Methods for studying of free-living herbivores zoochory
Lepková, Barbora ; Vojta, Jaroslav (advisor) ; Pokorná, Adéla (referee)
Epizoochory as well as endozoochory are well known dispersal mechanisms. This topic is being studied more and more often lately but our knowledge is still incomplete. The traits of plants dispersed this way are not yet well investigated and there is a gap in knowledge of mutual interaction between plant and animal species during transport. The impact of transport itself especially in endozooochory is also poorly known. We study endozoochory most often using seedling emergence method for seeds contained in dung. Feeding experiments are an interesting way of research and we use them to learn the survival rates of seeds in digestive tract. The most favourite methods for research of epizoochory are tamed animals and all types of dummies. Various laboratory experiments, for example shaking machine, are also frequently used.
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