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Natural regeneration of spruce stands in Vysoké Tatry (High Tatras) after large scale disturbation
Michalová, Zuzana ; Weiser, Martin (advisor) ; Wild, Jan (referee)
The observational study on natural regeneration of Norway spruce (Picea abies) was provided during seasons 2010 and 2011 in the windthrow area of High Tatra National Park. The main aim of this master thesis was to describe the distribution pattern in Norway spruce regeneration as well as to estimate the spatial scale, which most preciselly describes the differences in its phenotypic variability. Following step was to determine the relative influence of abiotic and stand factors on the growth characteristics and abundance of spruce seedlings. The Main focus lied on stressing the role of biotic interactions, like intraspecific and interspecific competition, leading to certain discrepancies in the phenotype, as well as in abundance of spruce seedlings.The reponse in variability in spruce traits was recognized at each spatial level. The results showed clear causality between soil moisture and vegetation composition, which both directly modified not only the phenotype of spruce seedlings and plants, but have even influenced their counts on particular stands.
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Sputtering of dust grains and its consequences for space processes.
Vyšinka, Marek ; Šafránková, Jana (advisor) ; Stöckel, Jan (referee) ; Wild, Jan (referee)
Title: Sputtering of dust grains and its consequences for space processes Author: Marek Vyšinka Department: Department of Surface and Plasma Science Supervisor: prof. RNDr. Jana Šafránková, DrSc., Department of Surface and Plasma Science Abstract: A great part of matter in a space has a form of dust grains, tiny pieces of rocks with the dimensions of hundreds nanometers to hundreds micrometers. In this environment dust grains undergo collisions with energetic particles (electron, ions, UV photons) that leads to their charging and modification. The presented thesis studies ion-dust interactions and is focussed on dust grain modification through ion implantation and its destruction via sputtering process. Two compu- ter models are presented - first for computing the ion implantation profile in the grain and second, for the shape of the sputtered grain lying on the surface of a bigger object. The resulting shape of the grain is compared with that obtained experimentally. Important results of the thesis are measured sputtering yields for spherical SiO2 grains at several surface potentials obtained by simultaneous ion and electron bombardments. Keywords: ions, dust grains, sputtering, sputtering yield, implantation profile 1
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Use of remote sensing data for monitoring of long-term vegetation dynamics on the landscape scale
Brůna, Josef ; Wild, Jan (advisor) ; Romportl, Dušan (referee) ; Kropáček, Jan (referee)
This thesis deals with the use of remote sensing data for studying and monitoring vegetation changes. Thanks to archival materials, we can now make extensive studies at the landscape and global level without the need for large-scale old field data. From the Middle Ages, we can rely on different types of maps, for vegetation studies, these are mainly forestry maps. Since the 1930's, aerial photographs have been available in Europe, and satellite imagery was available since the 1970's. Availability and quality of satellite imagery had increased rapidly during my study. The most recent data source are unmanned aerial systems and methods of processing their data, which allow inexpensive detailed mapping of large areas. The presented publications do not only solve ecological research questions, but also contribute to solving current environmental problems in the Czech Republic, from nature conservation in National Parks and protected areas to monitoring of plant invasions. I have used archival forest maps for the reconstruction and analysis of large disturbances (windthrow and subsequent gradations of bark beetle) in forests of Šumava and the Bavarian Forest in 1868-1870. Species composition, as well as environmental factors derived from digital elevation model, were analyzed. The same topic was also...
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