Effects of climate change on soil microarthropod diversity and ecological function

The arctic region is currently facing great environmental changes of greenhouse-gas warming, with likely strong consequences for structure of plant and animal communities and ecosystem processes. The rates of the biological processes are mediated by tempe rature, season length, temporal and spatial distribution of snow and water conditions, i.e. factors predicted to undergo strong changes. At the same time, decomposition processes are moderated by the organisms themselves. Microbes and soil fauna use litte r and soil organic matter as energy, carbon and nutrient sources for biomass production and for their metabolic functions. Climatic changes may both directly and indirectly facilitate an increase in the mineralisation of soil organic matter by microbes an d microarthropods, which again may lead to increased nutrient availability. It is essential to reveal the diversity of species, species and population densities, life cycles, population dynamics and turnover in microarthopod communities to understand the effects on the decomposition processes. Experimental sites for investigation of effects of environmental changes on biological and physiological processes have been set up at Zackenberg, Greenland, and Abisko, Sweden. Here, intensive investigations of bio logical and biogeochemical effects of changed environmental conditions have been carried out. The ability of soil organisms to adapt to a changing environment will determine their response to climatic manipulations. The proposed research will be complemen tary to the ongoing research, and the role of the microarthropods in the system will be elucidated. Sampling will take place in existing field plots, in addition to establishing new field experiments specifically designed for this project. The main effort will be on functional aspects on ecosystem level of processes, and interactions at the level of the microarthropods, studied by experimental perturbations within the ecosystems, and by laboratory studies.