Das Projekt "Sensitivity and Response of the Treeline Ecotone in Rolwaling Himal, Nepal, to Climate Warming" wird vom Umweltbundesamt gefördert und von Eberhard Karls Universität Tübingen, Fachbereich Geowissenschaften, Abteilung Bodenkunde und Geomorphologie durchgeführt. Integrating field sampling/mapping, experimental treatments, remote sensing, geostatistics, GIS applications, and GIS-integrated modelling, the project aims at investigating the sensitivity and response of the treeline ecotone in Rolwaling Himal, Nepal, to climate warming using a landscape approach. Treeline response will be analysed focusing on spatially differentiated patterns and processes. Correlating varied responses to landscape- and local-scale site conditions and mechanisms (geomorphic controls, soil physical and chemical conditions, plant interactions associated with facilitation, competition, feedback systems) will then allow inferences on how the region-wide climate warming input and finer-scale modulators interact to govern non-uniform treeline response patterns. Building on that, scenarios of treeline dynamics under climate warming will be developed.
Das Projekt "Alpine ecosystems in a changing climate: experimental CO2 enrichment and warming" wird vom Umweltbundesamt gefördert und von Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft, Eidgenössisches Institut für Schnee- und Lawinenforschung durchgeführt. Within the next decades, a two-fold increase in CO2 concentrations and a rise in temperatures by 1.4 to 5.8 C can be expected (IPCC 2001). Temperature changes in the past decades have been more pronounced in alpine and high-latitude ecosystems than in most other regions of the world (IPCC 2001). Alpine ecosystems are particularly sensitive to environmental changes because they represent a boundary ecosystem that is subjected to extreme climatic conditions. Since temperature and CO2 are key factors that regulate many ecosystem processes, the changing climate will have large effects on vegetation and soils. In this proposal, we intend to analyze effects of manipulated temperature and CO2 in alpine ecosystems at treeline. Our major aim is to study potential feedbacks between climate change, plant growth and ecosystem processes. Although the European Alps are certainly the most studied of all high mountain ranges in the world, predictions of potential impacts of climate change on ecosystems are mainly based on modeling studies or on observations of inter-annual and spatial variability. There are only a few attempts to manipulate climatic conditions in situ. A combination of an experimental increase in CO2 and temperatures in the Alps has not been carried out before. In the proposed project, we enrich experimental plots with CO2 using a FACE approach and increase temperatures with heating cables at the soil surface. The experiment has already been set up at a treeline site near Davos. The CO2 enrichment was started in 2001 and increased CO2 concentration to 550 ppm. During the 6th year of operation, as part of a co-operation with a French team, a parallel soil warming treatment was installed on half of the test plots in a crossed design with the CO2 treatment, which successfully increases soil and air temperatures by 3K. We aim at investigating the interactive effects of elevated CO2 and warming on plant growth, biodiversity and ecosystem responses. Our proposed study addresses the following key questions: Will effects of elevated CO2 persist in the longer term and will these effects change under increased temperatures? How does biodiversity and the dominant vegetation, i.e. dwarf shrubs vs. trees, react to elevated CO2 and warming? How does elevated CO2 and warming affect key ecosystem functions such as nutrient uptake and decomposition? The focus will be on the two major tree species European larch and Mountain pine and on the dominant dwarf shrub species, especially Vaccinium myrtillus and V. uliginosum. Measurements of plant growth will include length increment, productivity, phenology and reproduction. Changes in biodiversity will be monitored
Das Projekt "Funktionale Oekologie der Baumgrenze: eine synthetische Analyse von Baumring- und Klimadaten" wird vom Umweltbundesamt gefördert und von Universität Basel, Departement Integrative Biologie, Botanisches Institut durchgeführt. Auf Grund vorhandener Dendrochronologien wird die Wachstumsdynamik entlang von Transekten an der Waldgrenze studiert. Dies soll eine bessere Grundlage zur Erklaerung des Phaenomens Waldgrenze liefern und gleichzeitig Aufschluss ueber derzeitige Entwicklungstrends (Global Change) geben.