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Patterns and processes in spatial distribution of plant species across scales
Macek, Martin ; Wild, Jan (advisor) ; Lepš, Jan (referee) ; Zimmermann, Niklaus E. (referee)
In this thesis, I aimed to identify factors shaping plant distribution at different spatial scales, correlate them with environmental heterogeneity, identify causal processes and test general hypothesis on the nature of response curve shapes and species richness patterns. General review of the topic is introduced in the first chapter, followed by five chapters presenting three already published studies and two manuscripts. The first study deals with processes responsible for creation of fine-scaled spatial pattern of spruce seedlings and saplings, emerging after bark-beetle disturbance in mountain spruce forest. Aggregated pattern, replicating previous generation of spruce trees, emerges in consequence to microsite-dependent mortality, as was surveyed through repeated monitoring of the fate of individual seedlings. The second study explores spatial variability in forest understory temperatures at the landscape scale and its relevance for understory plant distribution. As the main source of variability in understory communities we identified seasonal maximum temperatures. Using GIS modelling approach, we created spatially continuous prediction, which outperformed state-of-art climatic grids used currently by ecologists. The third study on the shape of species responses along elevational gradients...
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The importance of woodlots and their ecological characteristics for birds in an intensively managed agricultural landscape
Rajmonová, Lenka ; Reif, Jiří (advisor) ; Šálek, Martin (referee)
Various types of woody vegetation are a key biodiversity refugee in intensively managed agricultural landscapes. However, the role of woodlots, representing an important type of such a vegetation, remains overlooked so far. Whereas the previous studies focused on the effect of their area, shape and isolation, consequences of variation in their habitat quality for biodiversity were not assessed up to now. This thesis is thus one of the first studies focusing on woodlots as a specific habitat for birds in agricultural landscape. My goals were: (I) to find out what is the bird community composition of woodlots in a Czech landscape, (II) to find out, what are the key habitat predictors of bird species richness and abundance in woodlots, (III) to describe differences in habitat preferences among various guilds and (IV) to formulate recommendations for conservational practice. I surveyed birds in 82 woodlots in an intensively managed landscape in Central Bohemia, Czechia, and measured variables describing woodlots' habitat quality together with woodlots' area, shape, isolation and types of surrounding land-use. I recorded numerous forest and non-forest bird species (57 in total), including some endangered farmland birds. The habitat variables showing significant relationships to bird community...
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Phytolith spectra of the recent vegetation in north-east Africa: testing the potential of phytolith analysis for palaeoecology
Kuncová, Kristýna ; Pokorná, Adéla (advisor) ; Jamrichová, Eva (referee)
Phytoliths are mostly formed by groundwater silica carried upwards in a plant's vascular system and consequently accumulated in different parts of the plant. After the plant's death, the phytoliths shaped in specific morphotypes are released into the soil. Phytolith assemblages found in the soil can therefore provide information on the previous vegetation cover. The use of phytoliths as a paleoecological tool is based on their high stability in a broad spectrum of environments, even in arid conditions which are usually not suitable for preservation of pollen grains and plant macro-remains. Analysis of surface phytolith assemblages linked to the parallel study of modern vegetation is offering a good opportunity to refine our knowledge of paleoecosystems of NE Africa by evaluating the interpretation value of the fossil data. Modern phytolith assemblages are usually interpreted by using their phytolith ratio to estimate the density of tree cover, the aridity, and the proportion of C3 and C4 grasses (Barboni et al. 1999). Here we show a comparison of soil phytolith assemblages on a 400 km long climatic gradient reaching from semidesert to short grass savanna. And we also show local variability in phytolith assamblages at one of localities in comparision with grass reference collection. This master...
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