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Influence of understory light on diversity and composition of forest vegetation in the České Středohoří Mts.
Macek, Martin ; Kopecký, Martin (advisor) ; Černý, Tomáš (referee)
Light is essential component of forest ecosystem, as limited light availability in forest-floor restricts herb and tree seedlings growth. Importance of light availability for maintaining plant species diversity and community structure wasn't sufficiently evaluated in the Czech Republic. This study focus on the ecological relevance of light availability on both landscape and local scale. Relationship of light to cover, diversity and species composition was quantified in the thesis. Dominant tree species affected light availability and its spatial variability. Light availability was along the soil reaction and slope most influential factor for large-scale species diversity. Within-site light variability affected plant diversity more than soil reaction variability. Measuring light by means of hemispherical photography seems to be an appropriate for studies like this. Light availability influnence on community compostition is weak in comparison with other environmental gradients.
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Comparison of drought effect on young coppiced and standard individuals of sessile oak
Stojanović, Marko ; Čater, M. ; Pokorný, Radek
Assimilation and photosynthetic efficiency (quantum yield) of young oaks were compared in coppice and standard sessile oak stands of comparable age (100-120 years) under different light intensity categories. Measurements of assimilation response were performed during three consecutive growing seasons (2012, 2013 and 2014). In every category 8 young oaks of generative origin and same number of coppice sprouts of different stool were measured. The quantum yield in optimal conditions in standards was highest in the category A of closed canopy, while in coppices in category C. During severe drought in 2013 the drop in efficiency of standards was evident in all categories, while in coppices no differences in efficiency were confirmed between optimal and drought stress, proving the advantage of young coppices over standards.
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Influence of understory light on diversity and composition of forest vegetation in the České Středohoří Mts.
Macek, Martin ; Kopecký, Martin (advisor) ; Černý, Tomáš (referee)
Light is essential component of forest ecosystem, as limited light availability in forest-floor restricts herb and tree seedlings growth. Importance of light availability for maintaining plant species diversity and community structure wasn't sufficiently evaluated in the Czech Republic. This study focus on the ecological relevance of light availability on both landscape and local scale. Relationship of light to cover, diversity and species composition was quantified in the thesis. Dominant tree species affected light availability and its spatial variability. Light availability was along the soil reaction and slope most influential factor for large-scale species diversity. Within-site light variability affected plant diversity more than soil reaction variability. Measuring light by means of hemispherical photography seems to be an appropriate for studies like this. Light availability influnence on community compostition is weak in comparison with other environmental gradients.
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Guideline for leaf area index estimation in non-mixed forest tree stands
Pokorný, Radek
This guideline introduces theory and methodological approaches for LAI estimation in forest stands, especially those which are user-friendly in the field as well as sufficiently accurate. These approaches include indirect methods, which use instruments with optical sensors. This guideline fills the gaps in the information given in the instruction manuals to these instruments. It gives a detailed description of how to assess whether the current conditions for LAI measurement are suitable, how to establish a grid of measurement points in a stand and what corrections to apply, etc. in order to obtain the desired value of LAI effectively and accurately.
Fulltext: content.csg -  PDF
Plný tet: Stanovení indexu listové plochy v nesmíšených porostech lesních dřevin_metodika_Pokorný R. - PDF
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Circadian activity of tadpoles of Phyllobates vittatus.
DOSTÁLOVÁ, Michaela
Tadpoles are known to behaviorally respond to visual, auditory or chemical cues. I examined the influence of group size and light conditions on the activity of Phyllobates vittatus. I performed laboratory experiments to measure locomotor activity. Activity levels of tadpoles were higher in the groups. Light conditions did not influence activity level of tadpoles. My results suggest that the group size is one of the main factors influencing tadpole locomotor activity of Phyllobates vittatus.
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Influence of the light conditions on herbaceous layer in mountain spruce forests in the Giant Mountains using GIS
ČIHÁK, Jan
Mountain forests are an important part of the landscape in our country. In the last three decades they have been seriously damaged by anthropogenic influence, especially immissions. The immissions make worse the health status of Norway spruce (Picea abies) forests, which cause changes in a structure of herbaceous layer, in which the health status of forest stand is reflected. The main goals of my work were to map the cover of herbaceous and mossy layers in two permanent research plots in the Giant Mountains ( Alžbětinka, Modrý důl), to create maps of herbaceous cover, to digitize them and to compare these maps with the extent in years 1993-1994 using a developing analysis in GIS and to detect influence of light conditions on herbaceous layer. Using digitizing and static evaluation of prepared detailed vegetation maps of the both permanent research plots, some important changes were found out in dominant soil cover categories. In the first research plot Alžbětinka, decline of the grass Calamagrostis villosa and increasing of Vaccinium myrtillus cover were evident. In the second research plot Modrý důl, decline of both investigated species, Avenella flexuosa and Calamagrostis villosa, was observed. Another goal of my research was to detect influence of the light conditions on herbaceous layer and nature regeneration of the Norway spruce on permanent research plot Modrý důl. Dependence of the basic categories of the soil cover on the percentual ratio of the light gaps in the crown canopy was proved. Dependence of the height of the seedlings on the ratio of the light gaps was also tested but it was not statistically proved. The negative dependence of survival on the ratio of the light gaps of the seedlings germinated in 1996 was proved, but not of the seedlings germinated in 2004.
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