Decomposition patterns, nutrient availability, species identities and vegetation changes in central-European summit bogs

The global increase in atmospheric nitrogen deposition leads to changes in decomposition activity, which has been observed especially in nutrient-limited bog ecosystems relying on atmospheric inputs as the sole source of external nutrients. We conducted a reciprocal transplant decomposition experiment in two bogs in central Europe to test the effects of Sphagnum species (S. fallax, S. magellanicum, S. rubellum/russowii, cellulose strips as controls), material origin and the environment on Sphagnum decomposition and related nutrient release. Cellulose, but not Sphagnum biomass, decomposed more rapidly in the warmer and nitrogen-richer conditions of the suboceanic Jizera Mts. than in the subcontinental Jeseniky Mts. In the Sphagnum biomass transplants, interspecific differences in decomposition overruled the effects of both the origin of the material and the environment of the decomposition site, with S. magellanicum decomposing the slowest. Possible relationships between decomposition rates and recent changes in Sphagnum species composition in N-polluted bogs are discussed.