Compositional and functional variation of vegetation behind the stability of boreal bog carbon sink Event

Event details

Boreal bogs are nutrient poor peatland ecosystems, characterized by strong spatial variation in water table and vegetation composition. Although the number of species is small in bogs, the spatial variability supports a large diversity of functionally different plant groups. We aimed to quantify how the spatially varying vegetation modifies the carbon sink of a boreal bog. Standing biomass decreased from dry to wet plant communities, but biomass production was even due to differences in biomass turnover rate among species. Respiration and gross photosynthesis were the highest in dry plant communities, but their symmetrical water table responses resulted in almost no differences in net ecosystem exchange among plant communities. However, the surfaces without Sphagnum mosses acted as carbon sources. Over the three studied years, the roles of plant communities in the ecosystem-level carbon sink changed. This indicates that the presence of species with different seasonal growth patterns and responses to environmental conditions could increase ecosystem resiliency. To verify this, the responses of functionally different components to environment should be included in process-models predicting the fate of bog carbon sink in changing climate.