CARBON BALANCE OF TUNDRA LANDSCAPE IN CEN TRAL SIBERIA - OBSERVATIONS, SIMULATION AND GIS-MODELING

Comprehensive statistical analysis of field measurements of CO2 fluxes in ecosystems of typical subarctic tundra in Taymir Peninsula (Centra l Siberia, Russia) was performed. Simulation models allowing to comput e integrate seasonal values of basic components of carbon balance in t he most characteristic plant communities of typical tundra were built. To access the landscape pattern of tundra carbon balance we applied G IS-approach based on the original computer map of ecosystem borders. I n 1994 the seasonal (from the beginning of snow melting till the end o f total soil freezing) carbon balance of typical tundra landscape was estimated as -4 g C . m-(2) . year(-1) (carbon sink), the ecosystem to tal respiration as +145 g C . m(-2) . year(-1), and gross primary prod uction as -149 g C . m(-2) year(-1). Such a poorly expressed carbon si nk conceptually should be considered as landscape equilibrium. Neverth eless the subsequent computer simulation of climate changes confirmed the hypothesis of positive feedback between global warming and change of carbon balance pattern in tundra ecosystems from sink to source. Fr om the other side we found that regional peculiarities of ecological a nd climatic conditions can strongly effect the climate global change a ppearance.