National Repository of Grey Literature 146 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Peat formation and peat meadow restoration
Krejčová, Jana ; Frouz, Jan (advisor) ; Picek, Tomáš (referee)
This work aims to clarify and describe the necessary conditions of the peat soil horizon formation. The following three types of locations were compared. Drained locations that were revitalized afterwards. Locations which were drained and never revitalized. And lastly undrained localities where the original peat horizons are still presented. It has been proven that the grounwater level differs in drained and undrained areas. However, there was no significant differrence between revitalized and non-revitalized areas in drained types of locations. The results confirmed that Sphagnum spp., which is the most important species in peat formation, dominates the plant community where the groundwater level is higher than 25 cm. If the grounwater level is lower than 25 cm below the surface, Sphagnum spp. disappears very quickly and degrades peat soil horizons. The work also proved the groundwater level directly affects plant comunities that more or less promote carbon accumulation in the soil but water level and anaerobic conditions have no direct affect on soil carbon accumulation and only affect the vegetation composition of the peat soil horizon.
Effect of selected biophysical factors on organisms and their anthropogenic modifications
Bujalský, Luděk ; Frouz, Jan (advisor) ; Šarapatka, Bořivoj (referee) ; Moldan, Bedřich (referee)
Univerzita Karlova, Přírodovědecká fakulta Ústav pro životní prostředí Charles University, Faculty of Science Institute for Environmental Studies Doktorský studijní program: Environmentální vědy Doctoral study programme: Environmental Sciences Autoreferát disertační práce Summary of Doctoral thesis Vliv vybraných biofyzikálních faktorů na organismy a jejich antropogenní modifikace Effects of selected biophysical factors on organisms and their anthropogenic changes Mgr. Luděk Bujalský Školitel: Prof. Mgr. Ing. Jan Frouz, CSc. Supervisor: Prof. Mgr. Ing. Jan Frouz, CSc. Praha, 2019 Abstract The PhD thesis is composed of four articles dealing with biophysical factors affecting the environment of organisms occurring in anthropogenically affected ecosystems. In spite of the apparent diversity of research areas, the basic unifying idea of this work is a concept that leads from individual factors to synthesis, or more precisely, deductions leading to an understanding of local ecosystem processes, but also trying to emphasize, recently a little overlooked in basic science, the concept of a holistic point of view of the functioning of natural phenomena accentuating the importance of the basic view of the world as "interconnected networks". In particular, this viewis a demonstration of a situation where anthropogenic...
Importance of ecological stoichiometry in soil development.
Veselá, Hana ; Frouz, Jan (advisor) ; Hruška, Jakub (referee) ; Bonkowski, Michael (referee)
Ecological stoichiometry is a useful tool for understanding of ecological dynamics and related processes. There are only rare informations about nutrient cycling and nutrient dynamics in plant- soil system in restoration areas after coal mining. Different plant species have developed own strategies and treat differently with nutrients which can influence nutrient cycling and consequent nutrient return to the soil. In thesis, I investigated ecological stoichiometry as one of key factors which controls soil development in post mining sites. In general introduction, known facts are summarized about e.g. plant traits, decomposition process, nutrient cycling and consequences for soil development and restoration practices. But still, relationship between leaves, plant litter, and soil is poorly understood in restoration areas. The results of a doctoral thesis are presented in five papers, out of which three have been published, one has been already submitted and one manuscript is prepared for publication in an international journal with impact factor. In the first presented publication, the influence of soil fauna was studied (especially earthworms) on soil development. Soil development differed significantly between sites afforested with different tree species and it is strongly influenced by the...
Use of nanomagnets treated materials in study of decomposition
Vyhnálek, Michal ; Frouz, Jan (advisor) ; Veselá, Hana (referee)
In study of soil organic matter, many methods of carbon labeling are used, mostly using carbon isotope 13 C, which are reliable, but require expensive devices. Magnetic nanoparticles could provide low-cost alternative, which can be prepared in most laboratories with basic equipment. The upside of nanoparticles usage is the fact, that we could monitor fate of individual particles added to soil, including their chemical transformations or changes in microbial communities. The goal of this paper was to test the usage of magnetic nanoparticles and prove the reliability of carbon labeling through experiment. KEY WORDS Magnetic nanoparticles, decomposition, soil organic matter
The growth of leguminous plants during primary succession in post-mining sites
Zedníková, Petra ; Frouz, Jan (advisor) ; Mudrák, Ondřej (referee)
Post-mining sites are characterized by unfavorable conditions limiting the rapid development of natural vegetation, which is particularly low nitrogen in the soil. Plants with symbiotic nitrogen fixation can be used for reclamation these degraded areas because they increase the nitrogen content in soil and accelerate the primary succession on the dump. The aim of this study was to evaluate the growth of three species of plants of the family Fabaceae, namely red clover (Trifolium pratense), bird's foot trefoil (Lotus corniculatus) and bird wetch (Vicia cracca), in differently old soils from dumps that were reclaimed and compare them to the growth in soils from areas that developed by spontaneous succession. Furthermore, to compare the changes in the growth of these species of plants in a situation where they grew separately in the soil compared to the growth in competition with grass (Poa compressa). Another aim was to evaluate the influence of the growth of these plants on soil properties during primary succession on the basis of measurement of various parameters in soil. The mentioned species of plants were sown into the sifted soils taken from the Velká podkrušnohorská výsypka after brown coal mining near Sokolov. The growth took place in a greenhouse for 5 months. Subsequently, above-ground and...
Autotrophic and heterotrophic soil respiration
Kopecký, Tomáš ; Frouz, Jan (advisor) ; Kukla, Jaroslav (referee)
The goal o f this study is to describe autotrophic and heterothrophic respirat io n on mine heaps near Soko lov (Czech Republic) through literar y research and a o ne year lo ng research on mine heaps. Resu lts show that the temperature and sit e difference have stat ist ica lly significant impact on respirat io n, however, at temperatures around 0 degrees celsius, there were significant increases in respiratio n on unrec laimed sit es. This pheno meno n needs to be explored by furt her research for our understanding o f natural succession dyna mics on mine heaps. Temperature was not statist ically significant for respirat ion o n unrecla imed sit es. That po ints to limit at ion o f respirat ion by another factor.
Soil water regime of reclaimed and unreclaimed post mining heaps
Cejpek, Jiří ; Frouz, Jan (advisor) ; Moldan, Bedřich (referee) ; Tesař, Miroslav (referee)
This PhD thesis compares the water regime of reclaimed and unreclaimed spoil heaps after brown coal mining, with special regard to the development of hydrological properties of soils, which are determinant for the movement and retention of water in the soil. The basic influence on the supply of soil water has the technology of pouring the spoil heaps and aging, which co-regulates the development of vegetation. During the development of soil's spoil heaps increases field water capacity and water retention, but also increases the wilting point. These changes are related to the accumulation of organic matter in the soil and the degradation of claystones to particle size of physical clay. The development of the ability of the spoil heaps soils to bind water is greater in reclaimed areas, where the upper organomineral horizon develops more rapidly, but there is also a wilting point and water consumption. On unreclaimed area, the soil substrate develops more slowly. Overall, the differences in water regime between reclaimed and unreclaimed areas are small.
Wood ant thermoregulation heat cluster formation
Slováková, Jana ; Frouz, Jan (advisor) ; Kadochová, Štěpánka (referee)
This study focuses on the influence of ant clusters on nest thermoregulation. The significance of this influence has been measured using temperature information from dataloggers about inner nest as well as ambient air temperature during the period from April 4 to June 4, 2016 and images capturing the ant mound surface for the same period. The results show that the ant clusters incidence rate and the size of the clusters are significantly affected by the inner temperature of the nest. The dependence of the cluster occurrence on the inner temperature is not linear but rather has the character of steep drops at defined temperature thresholds. In the temperature range of 0 - 7řC cluster occurrence significantly increases and reaches the occurrence peak at the upper limit of this interval, from 7řC to 21řC the cluster occurrence rate is significantly lower but relatively constant and at the temperature above 21řC there is a steep decrease. The occurrence of clusters is also significantly determined by climatic influences and insolation, with the measured data showing that after a precipitation or snowfall, the average cluster size is significantly larger compared to similar days without a precipitation or snowfall recorded. Keywords: Formica polyctena, thermoregulation, nest, temperature, ecology

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