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Determinants of Piper (Piperaceae) climber composition in a lowland tropical rainforest in New Guinea
LISNER, Aleš
The study examines the distribution of root climbers from the genus Piper on host trees depending on environmental properties and host tree characteristics in a lowland primary tropical rainforest in Papua New Guinea. More specifically, the study examines the relationship between the climbers' presence and various factors including topography (e.g. slope, altitude), vegetation properties, and host tree characteristics. The findings reveal that Piper climbers tend to avoid higher altitudes, steeper slopes, closed canopy layers, and areas with larger total basal area of host vegetation. The preferences of Piper climbers for certain tree species are primarily influenced by the properties of the host trees, particularly their diameter at breast height (DBH). Additionally, the study suggests that Piper species are more commonly found on rare tree species, possibly due to their preference for larger host tree DBH. The results highlight the non-random association between climbers and their host trees, which is influenced by local environmental conditions. These interactions are likely to have important implications for forest vegetation dynamics and the maintenance of diversity.
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Mechanisms behind diversity and ecosystem functioning relationships - the insights from observational and manipulative studies in grassland communities
LISNER, Aleš
This thesis focuses on the relationship between diversity and two commonly used ecosystem functions - productivity and its stability. The thesis tries to assess the problematics from different perspectives using large-scale observational studies and small-scale manipulative experiments to better understand which mechanism create observed patterns. High emphasis is put on the methodological aspects and potential theoretical or practical issues arising from experimental setting and data collection. More specifically, the thesis starts with description and critical evaluation of patterns observed at bigger spatial scales and across multiple sites (Chapter I). Then continue with detailed small-scale experimental approaches and assessment of mechanism driving relationship between diversity, productivity and stability of communities (Chapter II and III). Further, the thesis digs into bigger detail focusing on which plant characteristics define abundance patterns of individual species, which translates into productivity (Chapter IV). Finally, it elaborates on common issues related to vegetation data collection and their subsequent analysis (Chapter V).
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Intraspecific trait variability of plants in the succession on the Sokolov post-mining sites.
Říhová, Eva ; Mudrák, Ondřej (advisor) ; Lisner, Aleš (referee)
In primary succession, the colonization of plants is essential for the development of the ecosystem. Plants colonizing a disturbed site face a number of limiting factors, such as the adverse chemical and physical conditions of the substrate. In general, primary succession follows a trend of development from an unfavorable substrate to a substrate with available nutrients and water. Sokolov post-mining sites are an exception. Previous studies showed that in intermediate parts of the succession, plants should be the most limited by water, due to the formation of amorphous clay, which adhesively binds water. One of the ways how to determine the main limiting factors of plants and verify these assumptions is to study plant functional traits. The intraspecific shifts in functional traits during the succession may show how the plant environment changes for plants. In this thesis I have measured functional traits (plant height, specific leaf area, leaf area and leaf mass) of three species (Calamagrostis epigejos, Fragaria vesca, Tussilago farfara) at three spontaneously developing localities of Sokolov post-mining sites differing in age since heaping (2, 31, and 56 years). The intraspecific trait variability showed that the most limiting conditions for plant growth are at locality of intermediate age....
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Vztah diverzity a produktivity v travinných společenstvech a jeho mechanismy
LISNER, Aleš
The best estimates of environmental productivity and their relationship to species diversity on different spatial scales have been studied in grassland communities in an observational study. The fertilization effect on height, growth rate, survival rate and changes in species composition has been studied on an oligotrophic wet meadow in a manipulative experiment.
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