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Effect of vegetation structure on abundance of lowland forest birds in Czechia and Slovakia
Tyčová, Barbora ; Hořák, David (advisor) ; Chmel, Kryštof (referee)
The vegetation provides an ecological space for birds and its structure reflects the availability of this place and resources. What specific influence does the vegetation structure have on bird abundance and which vegetation parameters are the most essential for bird species are classic, but still topical questions. The aim of this work was to find an answer using a study focused on birds in floodplain forests and to determine whether microhabitat characteristics affect the distribution of bird species within a single habitat. The data of this work were collected by the point counting method in six floodplain forests of the Czech Republic and Slovakia and statistically evaluated using regression, correlation and redundancy analysis. The birds were observed on a larger and smaller spatial scale. It was also used the study of the saturation of the environment by bird species over time and for the first time the analysis of habitat photo documentation as an alternative way for describing the vegetation structure. Results show that the analysis of vegetation photographs can be used to explain and predict avian abundance and thus create a new suitable method for birds' studies. Some bird species such as the collared flycatcher (Ficedula albicollis) and the Eurasian blue tit (Cyanistes caeruleus) have...
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Ecological specializations of birds based on spatial co-existence patterns
Petrová, Kristýna ; Hořák, David (advisor) ; Weiser, Martin (referee)
Ecological specialization based on co-existence patterns is new methodology used for niche breadth measurement using co-existing community with occupancy data. It results in generalist-specialist continuum according to value of speciali- zation index. The aim of this thesis was testing index stability at spatial and tem- poral scale, compare this specialization index with other specialization indices and study changes in specialization with time changes in occupancy. Specialization was quantified using data of breeding birds atlases in the Czech Republic and Europe using two selected indices Theta and Simpson. Methodology seems to be sensitive to spatial scale. Instability appears at small scale for birds, stability and correlation between indices increase with gre- ater scale. Problems with using point counts corresponds to their unsuitability encompass birds' habitats, especially for water dependent birds. Correlations be- tween different time periods are stronger at greater spatial scale. Specialization based on co-existence patterns correlates with specialization according to experts' opinions. Results from comparing changes in specialization with changes in occu- pancy suggest, that most of species tend to leave more diverse sites with occupancy decline.
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Vztah diverzity a produktivity v travinných společenstvech a jeho mechanismy
LISNER, Aleš
The best estimates of environmental productivity and their relationship to species diversity on different spatial scales have been studied in grassland communities in an observational study. The fertilization effect on height, growth rate, survival rate and changes in species composition has been studied on an oligotrophic wet meadow in a manipulative experiment.
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