Poster, SOM 2010, Presqu’île de Giens: 2010-09-19 - 2010-09-23
Conservation of grasslands carbon storage characteristics is desirable in times of climate change. But ecosystem function and species composition of temperate grasslands are likely to respond to precipitation change (IPCC). Within FORKAST project carbon fluxes between atmosphere, biosphere and soil are investigated - especially under extreme weather conditions (droughts). Tracing of 13C and 15N after pulse labelling - accompanied by atmospheric (13)CO2 flux measurements (eddy covariance (EC), hyperbolic relaxed eddy accumulation) turned out as expedient approach. As expected, a decrease of organic matter input and lower turnover rates were observed at drought plots, compared to normal precipitation plots. Combining long-time EC (>1year) and chamber measurements of CO2-flux renders determination of drought influences on larger scale fluxes possible. Species specific changes in photosynthetic activity and modified assimilate translocation characteristics from leaves to roots and soil have also been detected. This can be a basis to evaluate stability and resilience of the species composition of the ecosystem under influence of extreme climate conditions.