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Start Over Creator Wild, Jan

2. Dynamika horských smrčin na Šumavě

Creator:
Vojtěch Čada, Brůna, Josef, Miroslav Svoboda, and Wild, Jan
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Botanika, smrk, Šumava (pohoří), 2, and 58
Language:
Czech
Description:
Understanding the history of coniferous forests and their natural changes over time is critical for proper and effective forest management. The text describes the origin and disturbance history of the mountain Norway Spruce (Picea abies) forests in the Šumava Mts. (Bohemian Forest) using tree-ring and archival documents analyses. Severe and extensive natural disturbances play and have played a fundamental role in forest structure and dynamics. Part of the territory has been shaped by forest management. and Vojtěch Čada ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Environmental correlates of the patterns of plant distribution at the meso-scale

Creator:
Petřík, Petr and Wild, Jan
Type:
article and TEXT
Subject:
biogeography, Ellenberg indicator values, flora, grid mapping, spatial autocorrelation, and variance partitioning
Language:
English
Description:
The distribution of vascular plants in grid-cells and its relationship to the environmental correlates (driving factors) were studied using numerical methods (divisive classification and ordination). The first level of division in the classification distinguished forest and non-forest groups of grid-cells, and the second level four groups (containing predominantly species of base-rich forests at high altitudes, species of acidophilous mountain forests and small mountain grasslands, ruderal and meadows species at low altitudes, and species of thermophilous and basiphilous fringes and abandoned meadows). Within the study area, geographically consistent areas were delimited by correlating the groups, indicated by the divisive classification, with altitude and forest cover. Most differences in the Ellenberg indicator values for species in these groups for light, temperature, continentality, soil reaction and soil moisture were statistically significant. A number of variables were effective predictors (e.g. potential direct solar irradiation), physical geography (altitude, slope), land-cover (forest cover, area of urban zones) and geological bedrock were the key determinants of the species composition in the study area. However, even the most spatially correlated (according to Moran’s I measure) were the naturally contiguous variables such as topographical features (altitude, slope and aspect). Generally, the grid-cells at low altitudes contained more species due to the co-occurrence of man-made habitats with fragments of semi-natural habitats. A relatively large percentage of the variation (15.8%) was accounted for by the spatial structure of the data, the environmental factors explained 18.9%, but 65.3% of the floristic variance remained unexplained. The most spatially autocorrelated variables were also the most correlated with regard to species composition. However, the relatively high autocorrelation in the species data and their derivates had comparable or lower effect on species composition than the most autocorrelated environmental factors. The results were compared with those of other European studies, and possible bias due to the different ways of collecting and analysing data, and effect of different scales discussed.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/

5. Katedra fyziky povrchů a plazmatu MFF UK se představuje

Creator:
Šafránková, Jana and Wild, Jan
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
Univerzita Karlova., Katedra fyziky povrchů a plazmatu, fyzika, vysoké školy, physics, universities and colleges, Česko, Czechia, 6, and 53
Language:
Czech and English
Description:
This short contribution presents six papers, which characterize research areas at the Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University. The joint research field is the interaction between particles, and particle interaction with gases, solid structures, and surfaces. in particular, the research concerns vacuum physics, physics of thin films and surfaces, plasma physics, and space physics together with their applications in diagnostics and modern technologies in material science., Jana Šafránková, Jan Wild., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Maps of the level of invasion of the Czech Republic by alien plants

Creator:
Chytrý, Milan, Wild, Jan, Pyšek, Petr, Tichý, Lubomír, Danihelka, Jiří, and Knollová, Ilona
Type:
article and TEXT
Subject:
altitude, archaeophyte, distribution, exotic species, habitat types, invasive species, land cover, neophyte, non-native species, and plant community
Language:
English
Description:
A series of maps showing the level of invasion of the Czech Republic by alien plants was developed based on a quantitative assessment of the level of invasion of 35 terrestrial habitat types at different altitudes. The levels of invasion were quantified for 18,798 vegetation plots, using two measures: proportion of the species that are aliens and total cover of alien species. Separate assessments were made for archaeophytes and neophytes. Within each habitat, the level of invasion was related to altitude using generalized linear models. The level of invasion, depending on the measure used, decreased with altitude in 16 out of 20 habitats for archaeophytes and 18 out of 23 for neophytes. In two habitats, one measure of the level of invasion increased with altitude for archaeophytes. The values of the level of invasion predicted by generalized linear models for particular combinations of habitats and altitudes were projected onto a land-cover map and digital elevation map of the country. Four maps showing the level of invasion were produced, based on the proportion of the species that are archaeophytes or neophytes, and cover of archaeophytes and neophytes. The maps show that both archaeophytes and neophytes are most common in lowland agricultural and urban areas, whereas they are sparsely represented in mountainous areas. At middle altitudes, agricultural areas are more invaded than forested areas. Outside agricultural and urban areas, high levels of invasion are found especially in lowland sandy areas and river corridors.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/

8. Použití dvousondové diagnostiky při měření vlastností plazmatu v nestandardních systémech

Creator:
Wild, Jan, Kudrna, Pavel, and Tichý, Milan
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyzika plazmatu, plasma physics, 6, and 53
Language:
Czech
Description:
We explain the measurement principles using a pair of Langmuir probes for the diagnostics of uncommon plasmas. The possibilities of the system will be shown using examples of the model flame and the plasma created by the interaction of extreme ultraviolet (XUV) laser with solids. The importance of contemporary data processing techniques supporting traditional methods will be also demonstrated., Vysvětlíme, jak funguje dvojice Langmuirových sond pro diagnostiku ne zcela běžného plazmatu. Její možnost demonstrujeme při experimentech s modelovým plamenem a plazmatem vznikajícím interakcí fokusovaného extrémního ultrafialového (XUV) laserového svazku s pevnou látkou. Ukážeme, jak bylo s pomocí soudobé techniky sběru a zpracování dat možné z obou studovaných systémů získat základní informace o plazmatu, tj. o teplotě a hustotě nabitých částic v něm., Jan Wild, Pavel Kudrna, Milan Tichý., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public