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Vliv světla na fotosyntézu bylin v podrostu doubrav
Zvyniatskovskyi, Yan
The forest environment is increasingly changing. Climate change brings along not only changed macroclimate. Stand microclimate is changing as well due to changes in tree species composition and the natural reduction in tree cover because of increased mortality. Understory herbs are sensitive to changes in the tree canopy cover. In sparse stands, more light reaches the understory compared to dense stands. Different understory herb species have different ability to use light and adapt to changing conditions. Short-term changes in their photosynthesis lead to long-term changes in species composition and their abundance. This bachelor thesis investigated the effect of different light availability on the photosynthetic parameters of understory herbs. I compared 8 taxa from four groups of Ellenberg ecological indicator values (EIV). The research was carried out in a stand of thermophilous oak-hornbeam in the Pálava Protected Landscape Area (PLA), on plots with different levels of tree canopy thinning. Herbs growing under fully stemmed stands plastically reduced respiration compared to herbs in the thinned forest, which allowed them to survive even under dense forest cover. However, they were still able to achieve high rates of photosynthesis under full illumination for short periods of time, i.e., they actively utilized short episodes of direct sunlight. Species characterized by EIH as shade-loving respired less in the dark than species with higher EIH in relation to light, suggesting a link between light availability and long-term abundance of herbaceous taxa. The results of this study suggest how the herbaceous understory of temperate forests might change in the context of climate change, with potential implications for forest typology.
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Intraspecific trait variability of herbaceous plants in organic and conventional olive plantations in region at desertification risk
MIGLIORINO, Michele
This thesis is an ecological study in an agricultural context (agroecological research). It is carried out in olive plantations in south Italy, Apulia, a region at strong desertification risk. The effect of agricultural management (organic vs. conventional) is investigated on i) the herbaceous species composition ii) intraspecific trait variability of five selected herbaceous plants iii) soil conditions. Herbaceous plants are here considered as "indicators" of olive plantations' health. Studying if and how species traits and soil parameters vary with management, should reveal how olive understory grasslands are responding to increasing drought conditions and other desertification constraints. Management of grasslands and soils is critical to maintain high ecological functionality and services of olive agroecosystems.
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Ecology of alpine plants at their uppermost limit in the Himalayas
CHLUMSKÁ, Zuzana
This dissertation studies the key abiotic factors and plant characteristics that influence the performance of the highest growing herbaceous alpine plants in Ladakh, Western Himalayas, and examines vegetation changes likely associated with climate change. The study site, located in the Rupshu region of eastern Ladakh, hosts some of the world´s highest-growing angiosperm plant species that occur above 6000 m a.s.l. The gentle slopes characteristic for the region, resulting in long elevational gradients, are particularly suitable for studying plant adaptations to the harsh dry and cold environment typical of whole Ladakh. The study presents novel insights into the causes of plant elevation limits and the direction of the vegetation shifts related to climate change at the very edge of the existence of angiosperms.
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