Technische Zusammenfassung

Die Technische Zusammenfassung des APCC-Sonderberichts ″Landnutzung und Klimawandel in Österreich″ umfasst die Kernbotschaften der Kapitel 1–9. In ihr sind die Hauptaussagen zu den sozioökonomischen und klimatischen Treibern der Landnutzungsänderungen, zu den Auswirkungen von Landnutzung und -bewirtschaftung auf den Klimawandel, zu Minderungs- und Anpassungsoptionen im Kontext nachhaltiger Entwicklungsziele sowie zu Synergien, Zielkonflikten und Umsetzungsbarrieren von Klimamaßnahmen enthalten

Systems Ecology: Ecological Network Analysis ☆

Ecological Network Analysis (ENA), based on network theory, is a methodology to quantify how objects interact with and depend on other objects in a system. Primary results from the method provide structural and functional properties of networks. A subset of ENA, Network Environ Analysis, divides the network into input and output “environs.” Application on empirical datasets and ecosystem models has revealed several important and unexpected results that have been identified and summarized in the literature. Data requirements for the analysis include the intercompartmental flows, compartmental storages, and boundary input and output flows. This article reviews the theoretical underpinning of several types of analyses of networks and briefly introduces some the main properties such as indirect effects ratio, network homogenization, network mutualism, ascendency and robustness. References for further reading are provided

Zooplankton metabolism in South African estuaries: does habitat type influence ecological strategies?

Zooplankton community composition, biomass and metabolism can vary drastically over space and time in subtropical estuaries. Changing environmental conditions can affect communities differently, depending on the characteristics of the species involved. In the present study, we compared the rates of oxygen consumption of the dominant zooplankton taxa living in permanently open and in temporally open/closed estuaries. The metabolic response was tested at four temperatures experienced by the animals in their natural environment. Zooplankton from the temporally open/closed estuary showed low activation energies and low rate of metabolism at the highest temperature tested. Animals from the permanently open estuary had higher respiration rates at increased temperatures than those from the open/closed counterpart, with one taxon showing a particularly strong response to temperature increase. Results suggest that the metabolism of zooplankton in subtropical estuaries can be influenced by the environmental conditions experienced and those characteristics need to be accounted for in the development of bioenergetics budgets of species and ecosystems

Variable nutrient stoichiometry (carbon:nitrogen:phosphorus) across trophic levels determines community and ecosystem properties in an oligotrophic mangrove system

Our study investigated the carbon:nitrogen:phosphorus (C:N:P) stoichiometry of mangrove island of the Mesoamerican Barrier Reef (Twin Cays, Belize). The C:N:P of abiotic and biotic components of this oligotrophic ecosystem was measured and served to build networks of nutrient flows for three distinct mangrove forest zones (tall seaward fringing forest, inland dwarf forests and a transitional zone). Between forest zones, the stoichiometry of primary producers, heterotrophs and abiotic components did not change significantly, but there was a significant difference in C:N:P, and C, N, and P biomass, between the functional groups mangrove trees, other primary producers, heterotrophs, and abiotic components. C:N:P decreased with increasing trophic level. Nutrient recycling in the food webs was highest for P, and high transfer efficiencies between trophic levels of P and N also indicated an overall shortage of these nutrients when compared to C. Heterotrophs were sometimes, but not always, limited by the same nutrient as the primary producers. Mangrove trees and the primary tree consumers were P limited, whereas the invertebrates consuming leaf litter and detritus were N limited. Most compartments were limited by P or N (not by C), and the relative depletion rate of food sources was fastest for P. P transfers thus constituted a bottleneck of nutrient transfer on Twin Cays. This is the first comprehensive ecosystem study of nutrient transfers in a mangrove ecosystem, illustrating some mechanisms (e.g. recycling rates, transfer efficiencies) which oligotrophic systems use in order to build up biomass and food webs spanning various trophic levels