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Modelling the onset of phenological phases of spring barley (Hordeum vulgare L.)
Dížková, Petra ; Bartošová, Lenka ; Hájková, L. ; Balek, Jan ; Bláhová, Monika ; Bohuslav, Jakub ; Pohanková, Eva ; Trnka, Miroslav ; Žalud, Zdeněk
The onset of phenological phases of plant species is influenced mainly by air temperature. Each phenophase has its temperature limits (base temperature and temperature sum), which must be reached for each phase to occur. With knowledge of these limits, it is possible to predict the onset of phenological phases in localities where only meteorological data are available and also in future climate conditions. In this work, we used phenological ground-based data from 33 stations within the Czech Republic to calculate the most relevant meteorological predictors. PhenoClim software was used for phenological and meteorological data calibration and modelling. The smallest error that allows us to predict the term of the phenophases was found for the heading of spring barley (Hordeum vulgare L.), as the best predictor was the maximum daily temperature and the statistical error was 3.6 days.
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Plant adaptation to climate change
Koláříková, Veronika ; Münzbergová, Zuzana (advisor) ; Sklenář, Petr (referee)
Climate change represents important selective force for plants. They have to deal with this change otherwise they are facing the risk of extinction. Understanding the mechanism which plants use to avoid the risk is essential for effective conservation of biodiversity. The climate change can exceed the tolerance of plants to abiotic factors. The plants can react to the changes by migration, phenotypic plasticity, evolutionary adaption or by a combination of these strategies. Phenotypic plasticity and evolutionary adaption are manifested by a change of physiology, morphology and/or phenology of plants. This work summarizes the findings of these ecological and evolutionary strategies and also presents methods used for studying species response to climate change. Powered by TCPDF (www.tcpdf.org)
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Optical properties of the leaf in relation to its anatomical traits
Neuwirthová, Eva ; Albrechtová, Jana (advisor) ; Tomášková, Ivana (referee) ; Písek, Jan (referee)
Plant functional traits at the leaf level are commonly used to predict ecosystem responses to environmental factors and describe global climate change processes at the ecosystem level. Plant functional traits include both leaf biophysical traits (e.g., photosynthetic pigment content and water content) and structural traits (e.g., leaf thickness and proportion of photosynthetic and non-photosynthetic tissues). Leaf biophysical and structural traits can be detected either destructively in the laboratory or non-destructively using leaf optical properties. Although estimating chlorophyll content from leaf optical properties is a well-established methodology, the influence of leaf structure and internal anatomy on leaf optical properties has only been thoroughly studied in the last two decades. The papers included in my thesis and my thesis itself are mostly focused on the study of typical European deciduous trees of temperate and hemiboreal forests with leaves having a dorsiventral structure (i.e., the mesophyll is differentiated into palisade and spongy parenchyma). Furthermore, my thesis includes a study on the effect of leaf surface structural traits on optical properties. In this study, two groups of phylogenetically close herbs with comparable internal leaf structure were used (mutants of...
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Assessment of vegetation phenology using Sentinel-2 time series data
Danilchyk, Tatsiana ; Štych, Přemysl (advisor) ; Bohovic, Roman (referee)
This work aims to evaluate the detection of phenological phases of vegetation based on phenometric parameters according to archival Sentinel-2 data in the selected areas over the period 2018-2020. The first part of the work describes literature review of the relevant publications, which is followed by the description of the suggested methodology. Then, there are the results with the graphic material and description for each monitored site. In the final part of the work, advantages and disadvantages of the developed algorithm are discussed followed up by suggestions for future research and improvement. The developed algorithm consists of two parts. Masking out cloudy and cloud shadow pixels and generation on the vegetation indices time series is done in the GEE platform. The time series analysis and detection of SOS and EOS as well as statistical analysis are done in the R environment. The study areas of size 20 x 20 m represent different species of perennial vegetation across the Czech Republic. For the assessment of the phenophases detection are selected NDVI, RENDVI, NDRE, NDMI and MCARI. The Asymmetric Gaussian function and Double Logistic function are fitted to the time series of each vegetation season in each tested site, the phenology metrics are derived based on threshold or derivatives...
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How does the current climate change affect the phenology and physiology of selected Central European flood-plain forest tree species?
Vokálová, Karolína ; Lhotáková, Zuzana (advisor) ; Konrádová, Hana (referee)
Floodplain forests are biodiversity-rich ecosystems found in many parts of Central Europe near watercourses and are part-time flooded during the course of the year. Floodplain forests are currently facing changes in environment related to climate change, for example increasing temperature and drought, elevated CO2 levels and excessive flooding. Woody plants respond to these changes by shifting the spring phenological phases, increasingly earlier onset of bud break occurs among different tree. Furthermore, there are various physiological, anatomical and morphological adaptations to these changes, through which plants try to avoid their damage. The plant response to changing environment is influenced by many endogenous factors, such as the degree of tolerance to flooding, the type of wood structure, position of a species on the isohydry-anisohydry scale or plant age, in addition to external factors, to which an extent of stress factor effect and its duration belong. In the future, a further increases in the average temperature, the CO2 concentration in the atmosphere and above-average flooding are expected, therefore it is important to understand the complex reactions and adaptations of floodplain forest trees to these changes in order to manage effectively these ecosystems.
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Phenology of mangroves
Hradečný, Jakub ; Koubek, Tomáš (advisor) ; Sklenář, Petr (referee)
The mangroves are a globally important ecosystem with an important value for many organisms, humans included. Many of the organisms are addicted to leaf production, as a part of their diet. These foliovorous organisms are directly affected by mangrove phenology, which presents differences on the global scale. It seems possible that the phenology is influenced mainly by annual temperature oscillations and its changes mark the start and the end of phenological periods. The phenology of mangroves can be influenced by another climatic factor too, as for instance rainfall or salinity. In the latitudes of 20ř, the phenological phases show unimodal mode with the long duration of phenology periods, usually longer than one year. Closer to the equator, the phenology of the plants becomes to change into a bimodal mode, with more than one peak of phenological event per year. In the area of the equator, the phenology of the plants changes into a multimodal mode, without differences during the whole year. This ideal model can be changed by local climatic extremes changing the mangrove phenology into a different mode.
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MICROCLIMATIC INFLUENCES ON WOOD PHENOLOGY OF TREES AND SHRUBS IN TREELINE ECOTONE
Hejda, Tomáš ; Treml, Václav (advisor) ; Chuman, Tomáš (referee)
This thesis deals with the influence of microclimatic conditions (air temperature near tree/shrub top, temperature of the stem and root zone) on the wood phenology of trees (Picea abies) and shrubs (Pinus mugo) growing on the same site in the alpine tree line (ATL) ecotone. Phenological and microclimatic research was carried out in the Giant Mountains at 1,370 m a. s. l. in the 2017 vegetation period, with the aim to compare the course of wood formation depending on the microclimate, to determine the temperature thresholds of wood growth and differences in the morphology of trees and shrubs. Based on the microclimate analysis of trees and shrubs, individual variables were determined (average, average minimum, average maximum, daily amplitude of air, stem and root zone temperatures) characterizing the growing season. The collection of micro-drills of trees and shrubs took place from April to October in an interval of 6 - 11 days, which were subsequently processed and examined in the laboratory. The following phenophases of wood development were distinguished: cambial, enlarging, wall-thickening, mature cells and cells of the previous ring. Subsequently, differences in the number of cells of individual phenophases were identified between trees and shrubs. Furthermore, the temperature thresholds for...
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Role of phenology in differentiation of plant niches: quantitative and comparative approach using a large set of species
Huang, Lin ; Herben, Tomáš (advisor) ; van Kleunen, Mark (referee) ; Dostál, Petr (referee)
Niche differentiation is the most recognized species coexistence mechanism, of which, the temporal differentiation of species, i.e. phenological differentiation has gained an increasing interest of ecologists. However, as an important dimension of phenology, the phenology of growth has drawn relatively few attentions due to the lack of sufficient phenological data. Therefore, the aim of this thesis is to examine potential role of temporal differentiation of plant growth patterns in plant coexistence. I first collected data on growth phenology of 381 perennial herbs in the Botanical Garden of Charles University in Prague within one growing season (in 2015). Using this database, I addressed the general patterns of growth phenology among perennial herbs. I distinguished two contrasting growth patterns: (1) species with early peak growth had high standardized growth rates in contrast to late species, reflecting the survival under forest canopy, where species are selected to grow early and fast before the development of tree canopy which restricts their size; (2) tall species showed later peak growth than short species, associating with (asymmetric) competition for light in open habitats, where the main selection factor is for tall stature, which cannot be attained early in the season. Then, by linking...
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Plant adaptation to climate change
Koláříková, Veronika ; Münzbergová, Zuzana (advisor) ; Sklenář, Petr (referee)
Climate change represents important selective force for plants. They have to deal with this change otherwise they are facing the risk of extinction. Understanding the mechanism which plants use to avoid the risk is essential for effective conservation of biodiversity. The climate change can exceed the tolerance of plants to abiotic factors. The plants can react to the changes by migration, phenotypic plasticity, evolutionary adaption or by a combination of these strategies. Phenotypic plasticity and evolutionary adaption are manifested by a change of physiology, morphology and/or phenology of plants. This work summarizes the findings of these ecological and evolutionary strategies and also presents methods used for studying species response to climate change. Powered by TCPDF (www.tcpdf.org)
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Climatological and phenological conditions of Tušimice observatory
Hájková, Lenka ; Sládek, Ivan (advisor) ; Láska, Kamil (referee) ; Žalud, Zdeněk (referee)
The thesis is aimed at climatological, agroclimatological and phenological conditions at Tušimice observatory during 45 years of observations (1968-2012) on basis of meteorological and phenological data by using statistical methods, method of cumulative series and geographical information system. Basic climatic elements (air temperature, precipitation total, snow cover, cloudiness, wind, humidity, sunshine duration, fog and thunderstorm), agroclimatic characteristics according to the WMO recommendation, selected phenological phases (mainly beginning of flowering 10 %) of herb and wooden species were processed in the study. The literature overview was made on climatic and phenological conditions at Tušimice station, in the Czech Republic and other countries. Apart from statistical analysis, the elements were also evaluated in the interaction with the changing air circulation in Central Europe. In addition, results were compared to Quitt's classification based on long-term averages of meteorological data (1961-1990 versus 1981-2010). The drought occurrence was evaluated in 45 years of observations period. The thesis is divided into three main parts - Climatic conditions of Tušimice observatory (part 5.1), Agroclimatic conditions of Tušimice observatory (part 5.2) and Phenological conditions of...
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