Climate and soil change nutrient element allocation of Siberian larch in the Mongolian semiarid forest

• Ecological stoichiometry was conducted for drought-stressed semiarid forest. • Accumulation and stoichiometric ratio were affected by both climate and soil. • Soil N was the main factor affecting ecological stoichiometry in leaves. • MAP was the main factor affecting ecological stoichiometry in branches. Ecological stoichiometry of nutrients regulates both tree growth and resilience to environmental stress. Exploring the accumulation of nutrient elements and changes in ecological stoichiometry under a drying climate is critical to understand the responses of drought-threatened trees in semiarid region to climate drying. Here, we conducted large-scale sampling of Larix sibirica -dominated forest patches of different sizes at 5 sites with different mean annual precipitation (MAP) in semiarid northern Mongolia in August 2017. The results showed that the accumulation and the stoichiometric ratio of elements in plants were affected by climate factors and soil factors. Soil N (44.9%) and MAP (29.9%) explain most of the total variance of ecological stoichiometry in leaves, while MAP explained 64.5% of the total variance of ecological stoichiometry in branches. The N and P contents in both the leaves and branches of Larix sibirica significantly increased, while the C:N and C:P ratios in leaves and the C:N ratio in branches significantly decreased with decreasing MAP ( P < 0.05). And the response trend of branch stoichiometry was larger than that of leaf stoichiometry. Our results imply that increased storage of nitrogen in branches might benefit trees to resist water deficit, which contributes to the assessment of ecological resilience to water deficit for trees in semiarid forests.