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[ACG30-05] Spatial variations in larch and soil nitrogen isotope ratio along forest-grassland gradient in northern Mongolia
Keywords:ecotone, Mongolia, nitrogen isotope ratio, plant and soil
In this study, we compare the nitrogen isotope ratio of single plant species (Larix sibirica Ledeb.) and soils along the forest-grassland gradient of a forest-steppe ecotone in Mongolia. Larch needles and soils were sampled during the growing season (May- August) from 2004-2012 at several sites in seven study areas.
The results showed the clear spatial pattern in needle, soil nitrogen isotope ratios, and its difference (Δδ15N)along forest-grassland gradient and the pattern corresponded to humus type (mor/mull). Δδ15N also had significant correlations with needle δ13C and C/N ratio of bulk soil, suggesting the Δδ15N change relates to water, light conditions and soil N availability. Isotope mass-balance model was applied to investigate the processes affecting the spatial pattern of Δδ15N.