关键词: 氮磷添加, 化学计量, 乔灌草群落, 大兴安岭

Abstract: To understand the responses of dominant species across different plant life forms in forests to nutrient addition, we conducted a field manipulative experiment with four nutrient addition treatments, including CK, N10, P2, and N10P2. We measured the stoichiometric traits and homeostasis of dominant tree, shrub and herb species, namely Betula platyphylla, Larix gmelinii, Alnus sibirica, Rhododendron dauricum, Elymus dahuricus and Carex tristachya. The results showed that: (1) Nitrogen addition increased leaf N content of the six dominant species, and phosphorus addition increased the leaf P content of these species, and simultaneous addition of nitrogen and phosphorus increased leaf N content of B. platyphylla, L. gmelinii, R. dauricum and C. meyeriana, with no significant effect on the leaf N content of P. lasiocarpa and L. chinensis, while also increased the leaf P content of R. dauricum, C. meyeriana, and L. chinensis, but did not affect L. gmelinii and P. lasiocarpa. (2) The variation of foliar N∶P ratios across the six species was jointly influenced by the changes in leaf N and P content, with N being the main limiting factor. (3) Under short-term nutrient addition, the stability of the three plant life forms (trees, shrubs, and herbs) of the Greater Khingan Mountains forest community showed the order: trees>shrubs>herbs. This study provides a new perspective on nutrient management and community succession predictions in boreal forests and offers a theoretical basis for the nurturing of boreal forests.

Key words: nitrogen and phosphorus addition, stoichiometry, tree, shrub and grass community, Daxing’an Mountains