Decomposition rate, and carbon and nitrogen dynamics of Sphagnum litter: lessons from a peat bog

Decomposition rates and changes of carbon and nitrogen contents of Sphagnum litter in mire vegetation can help to explore the ecological effects of climate change and the role of environmental factors from a local to an ecosystem scale. The objective of the study was to determine the relationship between mentioned parameters in small and isolated Sphagnum dominated mires. Measurements had been conducted throughout a year by placing litterbags filled with Sphagnum biomass in three vegetation types (open peat bog, poor fen, alder carr) of a mire ecosystem in Hungary. Peat decomposition rates differed to a great extent; the slowest decomposition rate (39.1 +/- 9.52%) was in the alder carr, indicating that slower decomposition could be characteristic for this kind of vegetation type of mire. Between Sphagnum dominated microhabitats, open peat bog showed medium (65.57 +/- 4.05) while poor fen the fastest (68.61 +/- 5.5) rates in decomposition. The C/N ratio of the Sphagnum litter showed significant decrease (P<0.005) in all studied micro-environments. Slower N release was observed from litter of Alnus dominated association (31.3 +/- 6.9%) compared to Sphagnum dominated ones (56.5 +/- 8.3%). Our findings showed that the decomposition rates were more dependent on vegetation type than C/N ratio and this relationship was also revealed at a small spatial scale.