Berninger, Frank Alexander

Köster, Egle

Köster, Kajar

Pumpanen, Jukka Sakari

Helsingin yliopiston digitaalinen arkisto

Geophysical Research AbstractsVol. 19, EGU2017-12058, 2017EGU General Assembly 2017© Author(s) 2017. CC Attribution 3.0 License.Grazing by reindeer in subarctic coniferous forests – how it is affectingthree main greenhouse gas emissions from soils.Kajar Köster (1,2), Egle Köster (1), Frank Berninger (1), and Jukka Pumpanen (3)(1) University of Helsinki, Department of Forest Sciences, Helsinki, Finland (kajar.koster@helsinki.fi), (2) EstonianUniversity of Life Sciences, Institute of Forestry and Rural Engineering, Tartu, Estonia , (3) University of Eastern Finland,Department of Environmental and Biological Sciences, Kuopio, FinlandReindeer (Rangifer tarandus L.) are the most important large mammalian herbivores in the northern ecosystems,strongly affecting Arctic lichen dominated ecosystems. Changes caused by reindeer in vegetation have indirecteffects on physical features of the soil e.g. soil microclimate, root biomass and also on soil carbon dynamics,and little is known about reindeer and their impact on greenhouse gas (GHG) emissions between the soil andatmosphere.In a field experiment in northern boreal subarctic coniferous forests in Finnish Lapland, we investigated the influ-ence of reindeer grazing on soil GHG (CO2, CH4 and N2O) fluxes, ground vegetation coverage and biomass, soiltemperature and water content. The study was carried out in the growing season of the year 2014. We establishedthe experiment as a split plot experiment with 2 blocks and 5 sub-plots per treatment that were divided into grazedand non-grazed parts, separated with a fence. The sample plots are located along the borderline between Finlandand Russia, where the non-grazed area was excluded from reindeer already in 1918, to prevent the Finnish reindeerfrom going to the Russian side and there are not many reindeer on Russian side of the area.Our study showed that grazing by reindeer significantly affected lichen and moss biomasses. Lichen biomasswas significantly lower in the grazed. We also observed that when lichens were removed, mosses were quicklyovertaking the areas and moss biomass was significantly higher in grazed areas compared to non-grazed areas. Ourresults indicated that grazing by reindeer in the northern boreal subarctic forests affects the GHG emissions fromthe forest floor and these emissions largely depend on changes in vegetation composition. Soil was always a sourceof CO2in our study, and soil CO2 emissions were significantly smaller in non-grazed areas compared to grazedareas. The soils in our study areas were CH4 sinks through entire measurement period, and grazed areas consumedmore CH4 compared to non-grazed areas. We also observed that the N2O emissions were significantly affected bymoss biomass and soil temperature. Non-grazed areas with lower moss biomass and soil temperature were a smallsink of N2O while the total fluxes remained around zero in the grazed areas.

Grazing by reindeer in subarctic coniferous forests – how it is affecting three main greenhouse gas emissions from soils

https://helda.helsinki.fi/bitstream/10138/232480/1/EGU2017_12058.pdf

Grazing by reindeer in subarctic coniferous forests – how it is affecting three main greenhouse gas emissions from soils

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