In den theoretischen Ansätzen der naturwissenschaftlichen Ökosystemanalyse stehen die Interaktionen von Populationen im Vordergrund, während das ökonomische System oft nur durch einen Parameter dargestellt wird. Umgekehrt wird in umweltökonomischen Modellen das Ökosystem häufig nur durch einen Parameter berücksichtigt. Dieses Forschungsprojekt zielt auf eine ausgewogenere Modellierung, die die Interaktionen innerhalb des Ökosystems, Interaktionen innerhalb des ökonomischen Systems und, besonders wichtig, wesentliche Interaktionen zwischen beiden Systemen berücksichtigt. Dazu wird im ersten Schritt die Leistungsfähigkeit ökonomischer Methoden in der Ökosystemanalyse untersucht. Im zweiten und zentralen Schritt werden ökonomische Modelle integriert mit Ökosystem-Modellen analysiert. Die methodische und theoretische Bedeutung des Forschungsprojekts liegt in der Bereitstellung innovativer statischer und dynamischer Allokationsmodelle, einschließlich der Multi-Spezies-Modelle, die Ökosystem und Ökonomie als gleichwertige Modellbestandteile behandeln und mit denen die Beziehungen zwischen beiden Systemen detaillierter als bisher analysiert werden können.
Glaciers around the world have retreated over the 20th century, which is also true of tropical glaciers. Although the characteristics of tropical glaciers (a high sensitivity to moisture-related climate variables) also apply to the glaciers on Kilimanjaro (Equatorial East Africa), studying their behavior requires a special view. This is because different glacier systems exist on Kilimanjaro: tabular-shaped ice bodies on the summit plateau, and slope glaciers below the summit plateau on the mountains steep flanks. The plateau glaciers are margined by vertical ice cliffs that - once they are established - lead to an irreversible areal recession of the plateau glaciers, regardless of the mass balance on the plateau glaciers horizontal surface. A preceding project could demonstrate that the main climatic reason of the current glacier retreat on Kilimanjaro (which commenced around 1880) is a regionally drier climate since the late 19th century, and that the glaciers show a much higher sensitivity to precipitation fluctuations than to air temperature changes. It also became clear that current climate pushes the glaciers close to disappearance, which raises the question under which climate conditions those glaciers could form and exist at all. The present project therefore aims at reconstructing at least 500 years of glacier history on Kilimanjaro and climate change in the tropics, to identify potential phases of an ice-free summit of Africas highest mountain. Since other precipitation-sensitive proxies (particularly lake levels) indicate greater climate fluctuations before 1880 than afterwards, it is likely that glacier existence on Kilimanjaro summit follows a relatively short-term cycle. On-site meteorological measurements with automatic weather stations will continue in the proposed project, in order to run.
Lakes can be considered as sentinels and thus indicators and integrators of environmental pressures such as climate change. To maintain lakes in a healthy ecological state is nowadays a major task for water management authorities, and will be increasingly so under climate change which is believed to negatively affect lake ecosystem functioning. Phytoplankton plays a key role in lake dynamics as it is at the base of the food web, and changes in its community have potential to affect the entire lake ecosystem. In addition, Cyanobacteria, the only freshwater phytoplankton group that is able to produce cyanotoxins, are capable of inflicting considerable harm to lake ecosystems and to human health through contamination of drinking water supply and toxin accumulation in fishes. Phytoplankton is thus a common indicator to assess the ecological status of lakes. Without understanding the complex mechanisms and processes that underlay a lake ecosystem in a changing climate, planning for future lake management and adaptation will be compromised. Numerical deterministic modelling is today the most appropriate approach to address these global and complex mechanistic features of lake ecosystems. Modeling studies play a key role in exploring the processes responsible for changes since they can be used to test the sensitivity of lakes to both observed and projected changes in climate. The aim of this project is to apply an ecological model to Lake Geneva, which has not been undertaken yet. Lake Geneva, a deep sub-Alpine lake, is the largest lake in central Europe and an essential source of drinking water, having not only a high ecological value, but also economic and social values. Due to its considerable environmental importance, it is crucial to assess, through numerical modeling techniques applied, how the Lakes water quality may be impaired; especially in view of the fact the observed rate of warming since 1900 is more than double that of the observed global average. Moreover, the hydrodynamic characteristics of Lake Geneva, the watershed of its most important inflow river Rhône, as well as the regional climate, have already been modeled. In coupling these models together, we will close the essential gaps, through which we will be able to understand the links between climate, watersheds, and lakes and provide a whole, integrated ecosystem perspective. This integrative model will provide an accurate predictive management tool to help take decisions and response strategies in a timely manner. It is generally recognized that future climate change will have an important impact on Lake Geneva, with a likely deterioration of its water quality. This will be manifested by high phosphorus concentrations, by phytoplankton biomass increase, by a change in phytoplankton composition, by an asynchronous phenology and by an emergence of potentially toxic Cyanobacteria.(...)