Are Chemical And Climatic Drivers Synergistic?

Studies on pine ecosystem functioning were carried out in different climates along a W–E transect extending more than 1500 km across Central-Eastern Europe (Germany-Poland-Belarus). Decomposition of litter in litter bags, measured at 13 locations simultaneously during 1995 and 1996 was correlated with components of climate: long-term annual temperature (TANN), temperature amplitude (TAMP) defined as the difference between temperatures of the warmest and coldest months, annual precipitation (PANN) and precipitation amplitude (PAMP). The content of eight metallic elements (Mn, Fe, Zn, Cu, Ni, Cr, Pb, Cd) was determined in litters from the same stands and correlations with decomposition rates were estimated. In those 13 pine stands influenced by gradually changing thermoclimate, the role of chemical factors was evaluated. It is suggested that similar interactions between decomposition, thermoclimate and metallic elements can occur in the case of climate change. In the warmer year, 1995, statistically significant correlations between decomposition rate and metal content or climatic factors were more frequent. Among the four fractions of litter analysed, needle litter responds most to the presence of climate and metals as regards its decomposition. Results from the calculation of partial correlations excluding the influence of various climatic factors suggest that a synergistic interaction might exist between two groups of factors driving decomposition processes, i.e. climate (in this case TANN, TAMP and CONT) and litter chemistry.