Reindeer (Rangifer tarandus L.) is considered to be an important mammalian herbivore, strongly influencing Arctic lichen‐dominated ecosystems. There is no wide knowledge about the effect of reindeer on greenhouse gas (GHG) fluxes in northern boreal forests. Ground vegetation plays an important role in absorbing nitrogen (N) and carbon dioxide (CO₂) from the atmosphere. Lately, it has also been found to be a significant source of nitrous oxide (N₂O) and a small source of methane (CH₄). We investigated the influence of reindeer grazing on field layer GHG (CO₂, CH₄, and N₂O) fluxes, ground vegetation coverage and biomass, and soil physical properties (temperature and moisture) in a northern boreal forest. At our study site, the reindeer‐induced replacement of lichen by mosses had contrasting effects on the GHG fluxes originating from the field layer. Field layer CO₂ efflux was significantly higher in grazed areas. The field layer was a CH₄ sink in all areas, but grazed areas absorbed more CH₄ compared to non‐grazed areas. Although total N₂O fluxes remained around 0 in grazed areas, a small N₂O sink occurred in non‐grazed areas with lower moss biomass. Our results indicated that grazing by reindeer in northern boreal forests affects GHG fluxes from the forest field layer both positively and negatively, and these emissions largely depend on grazing‐induced changes in vegetation composition.

中文翻译：

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驯鹿放牧对北方北方森林林地CO2，CH4和N2O通量的对比影响

驯鹿（Rangifer tarandus L.）被认为是一种重要的哺乳动物食草动物，对北极地衣主导的生态系统有强烈影响。驯鹿对北方北方森林中温室气体（GHG）通量的影响尚无广泛的了解。地面植被在吸收大气中的氮（N）和二氧化碳（CO ₂）方面起着重要作用。最近，还发现它是一氧化二氮（N ₂ O）的重要来源和甲烷（CH ₄）的小来源。我们调查了驯鹿放牧对场层GHG（CO ₂，CH ₄和N ₂O）北部北方森林的通量，地面植被覆盖率和生物量以及土壤物理性质（温度和湿度）。在我们的研究地点，驯鹿诱导的苔藓替代地衣对源自田间层的温室气体通量具有相反的影响。放牧地区的田间CO ₂外排量明显更高。场层在所有区域都是CH ₄汇，但与非牧区相比，放牧区吸收了更多的CH ₄。尽管放牧区的总N ₂ O通量保持在0左右，但少量N ₂O沉落在苔藓生物量较低的非放牧地区。我们的结果表明，北方北方森林的驯鹿放牧对森林场层的温室气体通量产生正向和负向影响，而这些排放很大程度上取决于放牧引起的植被组成变化。