| Summary: | Two bog ecosystems were compared by their ability to release CH 4 into the atmosphere during the warm season, and the influence of environmental factors (water table level and peat temperature) on CH 4 fluxes from the bog surface was studied. The studied bog ecosystems belong to the ombrotrophic bogs of the taiga zone of Western Siberia, but they differ significantly in vegetation cover, the structure of peat deposits, hydrological conditions, and temperature of peat layers. Methane fluxes were measured using the close static chamber method. The results show that CH 4 emissions vary from site to site depending on the local hydrological regime and the type of vegetation cover. The mean±standard deviations of the CH 4 emission flux from the open and forested bogs were found to be 2.66±4.58 mg m –2 h –1 and 0.57±0.69 mg m –2 h –1 , respectively. The calculated total CH 4 flux shows that the amount of CH 4 released from open bog is on average 4.7× higher than from forested bog, despite the fact that the former cover an area 1.5× smaller than that covered by the latter. The seasonal dynamics of CH 4 fluxes in both bog ecosystems are characterized by a July maximum and are closely related to peat temperature, but are not connected with the water level. In open bogs, the average daily CH4 emission variability was found to be 50% due to the influence of peat temperature at the depth of 10 cm, while in forested bogs it was found to be 39% due to peat temperature at the depth of 40 cm. The research results indicate a direct and very important link between the vegetation species composition and the hydrological regime of bog ecosystems in the estimates of the CH 4 flux from bog ecosystems in the region. This link causes high variability of the CH 4 fluxes at a small scale, which is often not accounted for when assessing CH 4 budgets of bogs and modelling responses of bog ecosystems to climate change. available online at http://www.borenv.net/BER/archive/pdfs/ber26/ber26-043-059.pdf
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