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Zhodnocení vlivu dřevin na stabilitu svahu v Žižkových sadech v Hradci Králové
Bradáčová, Alžběta
Among the most positive functions of trees in the cities are microclimate improvement and stabilization of slopes against erosion and landslides. The amount and distribution of water in the soil affect surface erosion and the stability of the slope. The aim of the study is to assess the influence of trees on the slope stability in a city park ‘Žižkovy sady’ in Hradec Králové. The study comprised of fieldwork, data processing, and hydrological modeling. During the fieldwork, the soils physical properties at the locality were studied under various types of vegetation cover. The soil moisture was measured under the trees and under the grassland from November 2015 to May 2017. Hydrological modeling in software PERSiST supported the soil moisture measurements, suggesting that trees have higher water uptake than other land use categories: grassland and paved area present in the locality. Modeled evapotranspiration was 30 % higher for trees than for grassland and 63 % higher for trees than for paved area, while total runoff for trees during the season was only 70 mm compared to 182 mm at the grassland and 447 mm at the paved area. The trees had a positive effect on the decrease of surface runoff through transpiration and interception, which mitigates of potential erosion and drains. Furthermore higher root diameter and rooting depth of trees than grass significantly improve slope ability. Potential tree removal on slopes of the locality may lead to increased erosion and landslides of existing slopes due to the excessive moisture in the low cohesive soils, the loss of anchoring roots and the increase of water infiltration into the soil.
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Hydrological processes and dynamics in the changing climate and environment: Lessons learned from multiple temporal and spatial scales
Su, Ye ; Langhammer, Jakub (advisor) ; Hanel, Martin (referee) ; van Meerveld, Hilda (referee)
Hydrological processes and dynamics in the changing climate and environment: Lessons learned from multiple temporal and spatial scales Ye Su ABSTRACT Climate change, along with the changes in land use and land cover (LULC), is the key factor driving the changes in hydrological processes and dynamics in a basin. This thesis emphasized on understanding the impact of both long-term climate change and abrupt anthropogenic driven agricultural intensification or natural driven insect-induced forest disturbance on hydrological processes and dynamics at varying spatial and temporal scales in two diverting terrestrial environment. Two pattern-based investigations, one case study in a forest region in Central Europe and another in a semi-arid region in Central Asia, were aimed to answer the main research question "what are the responses of hydrological dynamics and the related hydro-geochemical conditions to climate change and certain changes in LULC at a basin-scale?". The long-term hydro-climatic dataset was used for conducting statistical analyses and establishing hydro-climatic modelling at the basin scale. We further conducted process-based studies, attempting to understand how and why the specific hydrological dynamics were altered at smaller spatial and temporal scales: (i) a catchment-scale tracer-based...
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Soil water retention in the landscape
Hřebejková, Barbora ; Šípek, Václav (advisor) ; Frouz, Jan (referee)
Water retention in the landscape is one the current topics in environmental protection. It is affected by a number of factors and is changing both in time and space. The goal of this thesis is to examine the long-term development of water retention in the landscape and to determine the influence of different types of vegetation on the soil moisture underneath. In the first part of my thesis I review different soil types with respect to their physical characteristics and interaction with water, and ways of measuring soil moisture. The aim of the thesis is the sum up the basic knowledge about soil and basics behaviour, mainly in the relation with soil moisture. There are introduced methods of soil moisture measurement with regard to their limits. In the second part I focus on analysis of selected studies covering the topic of water retention in the landscape. Due to the technical difficulty is only a few studies devoted to a long term measurement of soil water by direct methods and therefore are results mostly limited to evaluate soil water retention by hydropedological models. In the final part I discuss and evaluate the results of the aforementioned studies. Key words: water retention, soil moisture, evapotranspiration, soil hydrology, climate change
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Temperature and humidity regime and energy balance characteristics of the stands with different management.
ŠACHL, Jiří
The aim of proposed thesis is identification and assessment of the impact of various types of vegetation cover on microclimate and local climate. The thesis study an issue of vegetation cover impact on the solar energy transformation, energy fluxes and an impact of vegetation cover on water cycle, mostly at the landscape level. Temperature-humidity characteristics and energy fluxes and their indicators (Bowen ratio, evaporative fraction) were monitored during the growing season in common types of vegetation cover occurring in agricultural landscapes (red clover - Trifolium pratense L., common wheat - Triticum aestivum L., potatoes - Solanum tuberosum L. and permanent grassland (TTP)) and wetland with predominantly tall sedge vegetation (e.g. Carex acuta L., Glyceria maxima (Hartman). Holmberg.). Results show a direct correlation between solar radiation and the amount of energy converted into latent heat of evaporation or sensible heat flux expressed through evapotranspiration. The results of analyses confirmed the theoretical assumption that the vegetation cover significantly influences microclimate, e.i. air temperature and humidity both of itself and surrounding area. The temperature-humidity characteristics were significantly different in the monitored stands. From this findings is obvious that the different types of vegetation can affect local microclimate differently. Moreover, the results showed that the vegetation well stocked with water probably significantly affects the water cycle in the landscape.
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Functions of Exocyst Complex in the Regulation of Stomata Dynamics
Röder, Matěj ; Žárský, Viktor (advisor) ; Burketová, Lenka (referee)
Stomata are structures in plant epidermis which regulate contact between inner and outer environment of the plant by mediating their stomatal aperture. Many inner and outer signals contribute to the ontogenesis of the stomatal pattern. Guard cells undergo significant change of volume and surface during stomatal movement. This change of surface must be compensated by intracellular trafficking of membrane material because biological membrane has limited elasticity. Most of this trafficking takes place between plasma membrane and endosomal compartments. Complex exocyst is protein complex that ensures proper targeting of secretory vesicles to their destination on the plasma membrane. Function of this complex is essential for many cellular processes that require precise targeting of secretion. Mutation in gene Exo70B1 causes different development of the stomatal pattern. Plants with mutated Exo70B1 differ in stomatal size depending on the cultivation conditions more than wild type plant. Protein EXO70B1 is also directly involved in stomatal dynamics because mutants exo70B1 have retarded stomatal opening in response to light. This direct connection can be observed on the fluorescently labeled protein EXOB1 which significantly changes its localization during stomatal movements. None of these observed phenotypes is...
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Hydrology of mountain seepage lakes
Kohn, Tomáš ; Stuchlík, Evžen (advisor) ; Šobr, Miroslav (referee)
The aim of this thesis is a review of the hydrological balance of mountain lakes, focusing on lakes without ground outflow, or with a huge share of seepage upon the outflow. This thesis deals, step by step, with the methods of collecting data for each input and output to the hydrological system. It is also concerned with the possibilities of monitoring ground water movement and rainfall-runoff models.
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Environmental assessment of the Czech Republic based on Water Footprint
Žlábková, Jana ; Hák, Tomáš (advisor) ; Vačkář, David (referee)
This dissertation sets its goal in application of the water footprint indicator, which is a practical and multi-layered indicator of water sources consumption. Of human activities, agriculture presents the most significant demands on water sources consumption. Therefore I have turned my focus to the widely-discussed issue of biofuels production, because the input materials for production of this kind of energy are agricultural crops (in the Czech republic those are: oilseed rape, sugar beet, Indian corn and winter wheat). The calculated results of water footprints of the selected industrial crops (m3 /t) and of water footprints of the heating value units of that crops (m3 /GJ) offer us a concrete notion of energy requirements of water of that chosen industrial crops in the conditions of the Czech republic. Keywords: water footprint indicator, biofuels, oilseed rape, water consumption, biodiesel, bioethanol, evapotranspiration.
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Added value of green roofs
Hrachovina, Vojtěch ; Žák,, Antonín (referee) ; Petříček, Tomáš (advisor)
Introduction is focused on analyze green roof like a part of buiding construction, when thesis assembly principles of right proposal green roof layers. Main part describes characteristic properties green roofs at global impact. We get some added values after comparison with classic roof types. Master thesis consists of survey of added values of green roofs in these categories: life cycle assessment, microclima, outdoor climate, water retention. End of thesis devote to psychological effect of green roofs include questionnare about relationship between czech society and green roofs.
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Evaluation of the effect of radiation on evapotranspiration estimates and drought indices
Mairich, Pavel ; Matula, Svatopluk (advisor)
Abstract Evaluation of the effect of radiation on evapotranspiration estimates and drought indices The severity of drought can be inferred from water balance, of which evapotranspiration is a component. The evapotranspiration estimates are often based on the FAO 56 methodology with the net radiation as the main input. Usually, however, the latter is not directly measured. This study investigates to which extent can the direct solar radiation and the long-wave net radiation measurements be replaced by calculation according to FAO 56 with constant or locally optimised radiation coefficients or, for the long-wave net radiation, the coefficients according to Penman (1948). The problem is demonstrated on data from the Solar and Ozone Observatory in Hradec Králové for 2011 and 2012. On average, the estimates of solar radiation are satisfactory even with the standard coefficients and can be improved by local optimisation of the coefficients. The estimates for particular days may considerably differ from reality. The long-wave net radiation estimate according to FAO 56 is, on average, by about 30 % lower than the measured long-wave net radiation or an estimate thereof based on locally optimised or Penman's coefficients, with the average differences between any two of the last three methods much smaller (less than 9 %). The inaccuracy of estimates for particular days is considerable, too. The average reference crop evapotranspiration according to FAO 56 with standard coefficients is therefore considerably higher (by about 15 %) than analogous evapotranspiration obtained from the measured radiation or according to FAO 56 with optimised or Penman's radiation coefficients. The cause is that grass in the observatory was not irrigated. It therefore occasionally suffered from water stress and got overheated. The use of FAO 56 with the radiation inputs measured or calculated using other than the standard radiation coefficients may underestimate the evapotranspiration and the need for irrigation.
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Analysis of water requirements of the field crops in areas with frequent occurrence of drought.
Zábranský, Petr ; Soukup, Josef (advisor) ; Jan, Jan (referee)
Summary
Water resources are an important part of ecosystems. In the water balance of the landscape, the variability of climate, soil factors, as well as high diversity of vegetation play an important role. Evapotranspiration represents a major passive component in the water balance of the basin. Unlike forests, where the water balance is particularly predictable due to the long-term development of the stands, regular crop rotation in agricultural systems and agricultural practices may cause rapid changes in water balance during much shorter time. It may sometimes result in irreversible changes in ecosystems with impact on landscape biodiversity. An understanding of the limiting environmental factors and exact determination of the water demands of plants makepossible not only an improvement of yield parameters, but it is also condition for understanding of the agroecosystems sustainability in the cultural landscape.
Field measurements of actual evapotranspiration were carried out in the period 2007 to 2015 in Velvary (Budihostice) in the Central Bohemia region, 210 m above sea level in the rain shadow area around Slaný territory. In terms of the average annual water balance (CHMI, 2014), the locality is regarded as the area with the difference between the average annual precipitation and annual potential evapotranspiration totals in amount of -200 mm, so the potential evapotranspiration slightly exceeds precipitation. Field measurements were conducted on commonly managed areas with a minimum size of the experimental plots of 1 ha.
The measurements confirmed differences between the crop water demands during the growing season. Different values of the actual evapotranspiration as well as the Bowen ratio values were estimated for the observed crops depending on the growth stage of crops. The lowest values of actual evapotranspiration were detected for Zea mays and Sorghum bicolor. Higher water demands were shown by Triticum aestivum and Hordeum vulgare. On the contrary, the highest values of actual evapotranspiration were found in stands of Beta vulgaris and Medicago sativa. According to the values obtained for crop coefficients (Kc), the crops of Z. mays, S. bicolor and T. aestivum had about a quarter lower values of Kc compared with M. sativa and B. vulgaris crops in the main growing season. In this work, the daily values of Kc, which are the basic characteristics of moisture requirements for individual crop were determined and can be used modelling of hydrological processes in agro-phytocoenoses. The evaluation of moisture requirement of crops by the water flow in plants (determined by the sap flow method) showed the expected differences between S. bicolor and Z. mays plants. Water use efficiency (WUE) was significantly higher in plants of C4 type (Z. mays and S. bicolor) compared with the rest of observed plants of C3 type (T. aestivum and H. vulgare).
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