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Long term investigation of resveratrol content in moravian red wines in relation to climate conditions
Vrchotová, Naděžda ; Tříska, Jan ; Totušek, J. ; Balík, J.
The considerable commercial importance of wine together with the necessary quality control and investigation of the biological quality of constituent compounds leads to the development of adequate and reliable methods for the determination of macro- and micro-components in wine. Although wine contains a large amount of known compounds e.g. volatile (fl avour compounds), semi-volatile (phenolic) and non-volatile components (pigments), new compounds from all the above mentioned classes are still found in wine and are under heavy investigation, especially regarding their biological activity and their relation to the vinifi cation processes. Th e most signifi cant and famous due to the so-called French paradox is resveratrol-3,4´,5-trihydroxystilbene. Resveratrol is a stress metabolite formed in the grapevine in response to abiotic (UV irradiation) and biotic stresses (Botrytis cinerea). UV irradiation transforms trans isomer to cis form. But according the recent literature cis resveratrol could be also a result of organic farming – natural means of defence in organic viticulture against fungal infections. In our study we have investigated resveratrol content in diff erent vineyards in relation to annual mean temperature, precipitation and sun irradiation.
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Co-registration of chlorophyll fluorescence emission and 3D models of plants
Ryba, Tomáš ; Železný, Miloš
Chlorophyll fl uorescence is a powerful optical reporter signal yielding information about modulation of light use effi ciency. In standard imaging applications, fl uorescence transients are captured in 2 spatial dimensions and in time. Here, we demonstrate that it is possible to combine the information obtained in the 2D-t format with the 3D reconstruction of the entire plant using a process called co-registration. Two diff erent approaches to co-registration are presented here. Th e fi rst one is based on an image registration method, where the precise transformation parameters are iteratively estimated. Th is approach assumes that the initial position of a scanner is known and thus makes the method less general. To remove this assumption, a second approach can be used, which is based on analysis of a known calibration object. Th ere is no need to re-calibrate the system between individual measurements.
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Comparison of eddy covariance and bowen ratio energy balance method. Energy balance cloruse versus bowen ratio similarity assumption
Fischer, Milan ; Trnka, Miroslav ; Pozníková, Gabriela ; Sedlák, Pavel ; Orság, Matěj ; Kučera, J. ; Žalud, Z.
The Bowen ratio and the Monin-Obukhov similarity principles are based on the assumption that the eddy diff usivities for temperature and humidity are equal to each other under all atmospheric stratifi cations within turbulent surface boundary layer. However, several authors reported that this equality was violated under advective inversion or during the non-stationary conditions due to clouds passing by and sudden change of wind speed and direction. Th e inequality of the eddy diff usivity can lead to errors in the energy partitioning estimates by gradient techniques like the Bowen ratio energy balance (BREB) and the aerodynamical method, or methods based on residual energy balance such as the Penman-Monteith or Priestley-Taylor models. Th is study investigates two seasons of simultaneous measurement by eddy covariance (EC) and BREB above a high density poplar plantation at the Domanínek locality. Th e direct measurement of eddy diff usivities by EC is reinvestigating the validity of the long term measurement (since 2008) by BREB. Results showed unequal exchange coeffi cients with their mean 0.31 to 0.35 m2 s-1 for 2011 and 2012, respectively, favouring the transport of latent heat. Th is might be explained by the diff erent footprints of the BREB and EC methods, an undeveloped internal boundary layer or instrumental errors.
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Phenological response of flood-plain forest ecosystem during 1961-2011
Bartošová, Lenka ; Trnka, Miroslav ; Bauer, Z. ; Štěpánek, P. ; Možný, M. ; Žalud, Zdeněk
The presented study is focused on 50 years of phenological observations (1961–2011) of the herbs, shrubs, trees and bird populations and the phenological phases that create a continuous phenological sequence covering the whole spring aspect of the fl oodplain forest ecosystem. Th e phenological phases were observed for 5 herbs, 5 shrubs, 3 trees and 2 bird species. Th e phenological phases were observed as precisely as possible by only one observer during the whole time of observation. All observed plants and bird species showed statistically signifi cant shift s to the earlier time but the rate of shift ing among the parts of the fl ood-plain forest ecosystem was diff erent. Th e most progressive shift s were detected for herbs (the rate of shift ing was on average 13.9 days), followed by shrubs (phenophases advanced by 11.3 days on average), trees (phenophases advanced by 10.2 days) and fi nally by bird species (phenophases advanced by 9.6 days on average). Consequently the length of overlap of the chosen phenological phases was elaborated. Th e rate of shortening or lengthening of the overlap diff ers among all parts of the ecosystem and indicates not only the separation of phenophases but also no statistically signifi cant change in the length of overlap in each part of the ecosystem.
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Quality control and homogeneity testing of daily time series of eca ECA&D
Zahradníček, Pavel ; Štěpánek, Petr ; Farda, Aleš ; Skalák, Petr
For any meaningful climate analysis, it is necessary for analysed time series to be homogeneous, which means that their variations are caused solely by variations in weather and climate (Conrad and Pollak 1950). Th us, prior to any analysis, the need to homogenize data and check their quality arises. Unfortunately, most of the climatological series that span over decades, to centuries, contain inhomogeneities caused by station relocations, exchange of observers, changes in the vicinity of the stations (e.g. urbanization), changes in instruments, observing practices (e.g. diff erent formulas for calculating daily means, diff erent observation times), etc. In this work we focused on testing the quality and homogeneity of daily data produced by ECA&D. Th is is a free available dataset of daily meteorological elements from the European Climate Assessment & Dataset (http://eca.knmi.nl/). Th is database was used to create a regular grid of EOBS points, which are oft en used to validate climate models.
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Spatial heterogeneity of soil CO2 efflux in four different ecosystems
Dařenová, Eva
Manual measurements of soil CO2 effl ux on a larger number of positions can give precise estimation of CO2 effl ux from the investigated area and together with temporal dynamics, observed in continuous measurements, can provide a good view on the ecosystem carbon balance. In this study we investigated the spatial heterogeneity of soil CO2 effl ux in four diff erent ecosystems (spruce forest, beech forest, wetland, grassland). Soil CO2 was measured on a net of 25–65 positions using a manual measurement system. We tried to fi nd responsible factors for the heterogeneity and to determine a measurement protocol for the most precise estimation of soil CO2 effl ux. Th e highest respiration activity was observed in the spruce forest, the lowest in the wetland ecosystem, where it was caused by a high water table. In the wetland ecosystem, there was the highest spatial heterogeneity of respiration activity, which reached almost 60 %. Th is high heterogeneity was caused by the gradient of the water table depth. Contrary to this, the lowest heterogeneity was found in the grassland where it was only about 15 %. In the spruce and beech forest the heterogeneity ranged between 35 and 45 %. As infl uencing factors we investigated e.g. soil moisture, tree distance and amount of the above ground biomass.
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Natural disturbances in central-european mountain spruce forests. A basis for forest restoration
Edwards-Jonášová, Magda ; Čermák, Martin
Risk of natural disturbances is a frequently discussed topic in the context of mountain spruce forests and global climate change. Recently, large-scale natural disturbances such as bark beetle outbreaks and windfalls have appeared relatively more frequently in Central-European mountain spruce (Picea abies L.) forests, which led to the enforcement of salvage logging even in some protected areas. Our study was performed as part of a long-term observation of recovery of spruce forests aff ected by bark beetle and windfall with and without interventions in two Central-European national parks, Šumava National Park in the Czech Republic and Tatra National Park in Slovakia. Th e results proved the ability of spruce forests to recover unassisted even from stand-replacing natural disturbances. Th eir biological legacies, which include standing and lying dead wood, are important for natural regeneration of tree species, and provide critical habitats for particular forest species. In comparison to natural disturbances, the artifi cial disturbances resulting from salvage logging destroyed a substantial part of the natural regeneration, which led to the need for artifi cial reforestation. Th us, the non-intervention strategy appears to be the best option for restoration of disturbed forests in the zone of mountain spruce forests. Based on our results, we propose that natural disturbances be considered as a basis for forest regeneration and restoration of their natural structure.
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Remotely sensed NDVI as a support tool for agricultural drouhgt assessment
Hlavinka, Petr ; Semerádová, Daniela ; Trnka, Miroslav ; Lukas, V. ; Bohovic, R. ; Balek, J. ; Wardlow, B. ; Hayes, M. ; Tseagaye, T. ; Žalud, Zdeněk
Th e main aim of the submitted study was to introduce how the remotely sensed NDVI (Normalized Diff erence Vegetation Index) could be used for agricultural drought assessment within the Czech Republic. Th e relationship between NDVI values and observed yields of spring barley and winter wheat was analyzed for selected districts. Moreover the ability of NDVI (at district level in the form of seasonal greenness – SG) to explain the water balance or drought occurrence and severity was tested. For this purpose a data mining technique was used. A relative form of the Palmer Drought Severity Index (rPDSI) was used as a dependent variable to indicate drought occurrence. A Standardized Precipitation Index (SPI), percentage of average SG (PASG), Start of Season Anomaly (SOSA) and district identifi cation were used as independent variables. MODIS (Moderate Resolution Imaging Spectroradiometer) observations from the Terra satellite were used as a source of NDVI. Th e situation within 6 selected districts (Olomouc, Přerov, Znojmo, Břeclav, Žďár nad Sázavou and Havlíčkův Brod) during the period from 2000 to 2012 was analyzed. Promising results were achieved, so practical use of this approach (e.g. for spatial and temporal assessment of drought stress within the vegetation) could be expected.
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Towards the issue of ecosystem services of small watercourses in the Czech Republic
Jakubínský, Jiří
Th e issue of ecosystem services represents a hot topic especially in connection with quantitative expression of their values and research of functions, which the landscape provides to a human society. Th e question of ecosystem values research is solved with a focus on the river landscape, defi ned as the ecosystem along watercourses whose functioning is directly conditioned by the presence of the hydrographical network. Since it is a very attractive area for the implementation of human needs, there is oft en what is seen as a confl ict between activities of human society and the eff ects of natural processes. Catchment areas of small watercourses or their parts which are specifi c in terms of mutually diff erent intensity of anthropogenic pressure on the landscape were selected as the model sites. Th e main aim of this paper is to analyse the relationship between the value of landscape ecosystem services – either usage of existing methodologies for ecosystem valuation, the rate of small watercourse degradation and changes in their natural parameters (morphology of the river channel and riparian zones).
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Precipitation variability in the czech land since ad 1500. How strong is the signal contained within documentary sources?
Dobrovolný, Petr ; Brázdil, Rudolf ; Trnka, Miroslav ; Kotyza, O. ; Valášek, H.
Past climate may be reconstructed from a number of proxies. Some of them are “natural archives”, such as tree rings, ice cores and boreholes, most of which are sensitive to air temperature. Other valuable information can be also found in “man-made archives”. Various sources of documentary data very oft en refer not only to temperature but also to other aspects of past weather and climate, such as dry and wet periods. We use the long and homogeneous precipitation series from the recent instrumental period to calibrate precipitation indices derived from older documentary sources. Th e primary objective of this contribution is to provide a quantitative reconstruction of precipitation in the Czech Lands for the last 500 years. Calibration and verifi cation statistics are used to evaluate the strength of the signal. Reconstructed precipitation series are compared with similar Central European documentary-based reconstructions, as well as with reconstructions based on a range of natural proxies.
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