Global ETD Search

11	Nepůvodní druhy rostlin a biotická rezistence kolonizovaných společenstev / Alien species of plants and biotic resistence of invaded communities Kubátová, Michaela January 2011 (has links) Michaela Kubátová Alien species of plants and biotic resistence of invaded communities This study is about problems and questions of alien plants and their relation to native communities in their new range. Ecologists are increasingly aware that soil organisms may affect plant communities because they are part of the processes that affect them. The soil organisms may affect the success of alien species invasion. Each species of plants differ in interaction with soil organisms, these interactions can result in specific feedback that will influence the future growth of other plants. According to Darwin's naturalization hypothesis related species should have similar enemies. This implies less successful invasion of alien plants at home with relatives. The practical part consists of two experiments. Using plant-soil feedback I studied under controlled conditions the importance of kinship of native plants and their soil organisms on the growth of three species of alien plants Impatiens, Parviflora, Stenactis annua and Epilobium ciliatum. There were used soil samples from localities with related and unrelated species; the soil was used as inoculums for growing first-generation plants, where there were original related, unrelated and alien plants. In the second phase only alien species were grown. Part of...
12	Flows Form Forests: The Mangrove Groundwater Feedback Model MANGA Bathmann, Jasper 20 January 2022 (has links) Due to the wide range of provided ecosystem services of mangroves, their conservation, maintenance, and restoration is of major public interest. The distribution of species and plant growth forms in mangrove ecosystems is patterned in zones. The characteristics of these zonation patterns can provide evidence on ecosystem properties. There is ongoing discussion on the drivers leading to mangrove zonation. No full mechanistic explanation to understand the complete interaction of the multiple factors that determine the mangrove zonation patterns exists.Therefore, the underlying processes require deeper evaluation.This will help to better design mangrove conservation projects, and allow more reliable projections of ecosystem development in a changing climate. Numerical and conceptual modelling facilitates the understanding of system dynamics. In this work, I present the process- and individual-based mangrove population dynamics model MANGA. The mechanistic modelling approach is based on first principles. With the full coupling between a groundwater flow model and an individual-based mangrove growth model, MANGA provides a novel approach to study mangrove ecosystem dynamics. MANGA describes observed mangrove stand zonation in species distribution and plant growth forms as the consequence of the apparent site conditions such as hydrologic conductivity, porewater salinity distribution and the tidal regime. Model parameterization does not only depend on empirical evidence.Knowledge on the underlying processes can also be used for model calibration. Varying model boundary conditions and parameters provides insights to the influence of a variety of abiotic drivers on mangrove zonation. The MANGA model is capable to simulate the reaction of mangrove ecosystem to variations of environmental conditions related to climate change. According to MANGA simulations, for example, mangrove species composition depends on freshwater inputs which alter with varying precipitation regimes. Based on the presented applications of the mechanistic modelling approach, I discuss benefits and current limitations, and outline possible future use of the MANGA model. info:eu-repo/classification/ddc/570 ddc:570
13	Multifaceted effects of competition and plant-soil feedbacks on Achillea millefolium grown in soil from a riparian meadow : Emil Karlsson - Umeå University - Thesis project - 60 hp Karlsson, Emil January 2021 (has links) Competition between plant individuals and how plants alter soil properties are key processes which drive changes in plant communities over time. Estimating the relative importance of these processes and how they affect plant growth in different ecological contexts and communities is an active area of research. Furthermore, interdependencies between the two processes have been suggested to occur in many cases, but research in this area is also lacking. In this study, soil conditioned by common yarrow (Achillea millefolium) was collected from field plots and was then used in a growth chamber competition experiment, which controlled for plant-soil feedbacks. Measured soil properties such as soil pH, soil nitrogen, and soil texture were primarily used as background data in the experiment. Field parameters such as light availability, plant density, and grass to forbs ratio were used to predict optimal A. millefolium habitat in relation to other vascular plant species. The results indicate that A. millefolium was a weaker competitor than cornflower (Centaurea cyanus), while a positive plant-soil feedback effect was observed by A. millefolium grown in field soil. Intraspecific competition had a strong negative effect on A. millefolium growth when grown in non-conditioned soil, but not when grown in A. millefolium conditioned soil. Finally, competition and plant-soil feedbacks appeared to be additively affecting A. millefolium growth, meaning the plant-soil feedback effect did not have a disproportionate effect on competitive outcomes, or vice versa. The findings of this study can be of interest to conservationists or farmers who wish to predict how plant communities respond to plant competition and plant-soil feedbacks as processes. Plant Competition Plant soil feedback Yarrow Achillea millefolium Centaurea cyanus Soil pH Nitrate Ammonium Nitrogen Soil texture Light Sweden Height Biomass Field Growth chamber Greenhouse Ecology Relative fitness Stabilizing niche Konkurrens Jordmån Kärlväxter Röllika Blåklint Ecology Ekologi
14	The Spillover Effect Hypothesis: Using Mycorrhizal Associations of Temperate Hardwood Forests as Study Models for Community-Wide Plant-Soil Feedback Effects Eagar, Andrew Charles 27 July 2022 (has links) No description available. Biogeochemistry Bioinformatics Botany Ecology Environmental Science Evolution and Development Molecular Biology Plant Biology Plant Pathology Plant Sciences Soil Sciences Arbuscular mycorrhizas Ectomycorrhizas Microbial ecology Plant ecology Plant-soil feedback Soil ecology Spillover effects Temperate hardwood forests

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