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Holocene fire history of forest vegetation in central Europe based on soil and sedimentary charcoal
Bobek, Přemysl ; Kuneš, Petr (advisor) ; Feurdean, Angelica (referee) ; Chytrý, Milan (referee)
Fire is a fundamental environmental factor that directly shapes many terrestrial ecosystems on Earth. The present thesis attempts to provide a comprehensive overview of the fire dynamics in Central Europe over the course of the last 12,000 years. Based on extensive analyses of charcoal particles deposited in terrestrial and lacustrine sedimentary sequences and carbonized plant tissues deposited in soils, I was able to track past fire dynamics across a range of spatial scales - from the forest stand scale to the landscape scale. First, we described relationships between drivers of recent fire occurrence and proposed linkages to the spatial pattern of Late-Holocene biomass burning. We found factors related to relief characteristics, such as increased thermal flux or terrain roughness, to be important determinants of fire occurrence within the present-day landscape. Contrary to all expectations, anthropogenic drivers seem to have a weak influence at present. Because relief-based factors have been stable throughout the Holocene, it seems probable that habitats of certain types are more predisposed to increased burning. We hypothesized that recurrent fire disturbances may contribute to the long-term maintenance of Pinus sylvestris-dominated forests, which withstood the competitive pressure of broadleaf...
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Ecology of the pathosystem Vinca minor - Puccinia cribrata in natural populations
Vaníček, Jiří ; Koubek, Tomáš (advisor) ; Macek, Martin (referee)
5 Absctract Environment and demographic characteristics of host population are important factors affecting incidence and severity of plant diseases. The aim of this study was to reveal possible effects of microclimatic and edaphic characteristics and host population demographic factors on the biotrophic pathogen Puccinia cribrata, microcyclic rust parasitising clonal evergreen plant Vinca minor. I studied the ecology of this pathosystem in natural populations of V. minor in the Soča valley in the Julian Alps in Slovenia. Rugged terrain of the Soča valley with different bedrocks allowed to study pathogen distribution at topographically diverse forest and scrub sites, greatly differing in soil depth and canopy structure. P. cribrata was significantly more likely to occur in the themophilous forest with shallow calcareous soils and open canopy than in the mesophilous forest types. Its prevalence (proportion of diseased stems in population) was also highest in this type of vegetation. Most important host population factors were population size and population density positively affecting incidence and prevalence respectively. Additionally, I tested various vegetation and topographic indexes derived from remote sensing for usability in prediction models. It appears that vegetation indexes connected with canopy...
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The effect of different management strategies on the dynamics of saproxylic insect habitats
ŠEBEK, Pavel
The thesis concerns studies on habitats utilized by insects associated with deadwood. It presents a review of current issues in the conservation of saproxylic biodiversity. The effects of active intervention on temperate lowland woodland habitats, such as pollarding or coppicing, are evaluated in terms of their suitability for saproxylic communities and other groups. Further, the importance of open-grown trees for saproxylic diversity is assessed.
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CO2 efflux in different types of ecosystems
Dařenová, Eva
CO2 efflux from soil at three different ecosystems (spruce forest, beech forest, wetland) and from the whole ecosystem at one site (grassland) was measured during campaigns of manual measurements or automated continuous measurements during growing seasons 2008 -- 2012. There were determined factors driving spatial variability and temporal dynamics of CO2 efflux. Soil temperature was mostly the driving factor responsible for temporal dynamics and soil water content contributed to both temporal dynamic and spatial variability. Also the amount of grass or litter affected the variability. We also determined that time of the day when the measurements of soil CO2 efflux are done can influence estimation of seasonal sum of released carbon from soil. Finally, it was determined that changing precipitation pattern with simulated drought in the first half of the growing season has both immediate and long-term impact on CO2 efflux from the grassland ecosystem.
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The role of wood decay fungi in the dynamics of a mountain spruce forest
POUSKA, Václav
This thesis is focused on environmental preferences of wood-decaying fungi and their relationships with forest structure and development. Relationships of fungi to properties of wood and forest stands were studied on the basis of field observations in Central-European mountain spruce forests. Plot-based approach was used to reveal a general pattern in the diversity of fungi within a single forest stand and between different stands. The analysis of stand structure provided a background for plot-based approach. Substrate-based approach was used to study single species preferences and their communities. In addition, the influence of wood properties (including fungi and their rots) on the regeneration of spruce on logs was studied.
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