高原鼠兔有效洞穴密度对高寒草甸优势植物叶片和土壤氮磷化学计量特征的影响

采用有效洞穴密度代替高原鼠兔(Ochotona curzoniae)活动强度的方法,研究了高原鼠兔有效洞穴密度(10、15、21和31个/625 m~2)对高寒草甸优势植物高山嵩草(Kobresiapygmaea)、垂穗披碱草(Elymus nutans)、小花草玉梅(Anemone rivularis)叶片和土壤氮(N)磷(P)化学计量特征的影响。结果表明,3种优势植物叶片N含量随有效洞穴密度增加而显著增加(P0.05),但叶片P含量却出现分异,表现为高山嵩草和垂穗披碱草叶片P含量随有效洞穴密度增加而先增加后降低(P0.05),小花草玉梅叶片P含量逐渐增加(P0.05);高山嵩草叶片N:P随有效洞穴密度增加先降低后增加(P0.05),垂穗披碱草叶片N:P逐渐增加,小花草玉梅叶片N:P则先增加后降低。土壤0-10 cm和10-20 cm土层N含量随有效洞穴密度增加无明显变化;0—10cm土层P含量随有效洞穴密度增加先降低后增加,10—20 cm土层P含量逐渐降低;0—10 cm土层N:P随有效洞穴密度增加元明显变化,而10-20 cm土层N:P则逐渐增加。优势植物叶片N、P、N:P与土壤N、P、N:P的相关性受植物根系分布特征和生存微环境的约束。

Effect of available burrow densities of plateau pika (Ochotona curzoniae) on leaf nitrogen and phosphorus stoichiometry of dominant plants and soil in alpine meadow

A field survey was conducted to determine the effect of available burrow densities of plateau pika with 10, 15, 21 and 31 per 625 m² on leaf nitrogen (N) and phosphorus (P) stoichiometry of dominant plants and soil of alpine meadow by using available burrow density substituting for activity degree of plateau pika in this study. The dominant plant included Kobresia pygmaea, Elymus nutans and Anemone rivularis var. flore-minore. This study showed that the leaf N content of K. pygmaea, E. nutans and A. Rivularis significantly increased as the available burrow density increased (P < 0.05). The leaf P content of K. pygmaea and E. Nutans firstly increased and then significantly decreased (P < 0.05), and leaf P of A. Rivularis increased gradually (P < 0.05) with the increase of available burrow density. The leaf N:P was different among three dominant plants, indicating that the leaf N:P of K. pygmaea significantly decreased (P < 0.05), and the leaf N:P of E. nutans increased gradually, but that of A. Rivularis firstly increased and then decreased as the available burrow density increased. This study also showed that the soil N content at 0-10 cm and at 10-20 cm layer was similar as the available burrow density increased. The soil P content at 0-10 cm layer firstly decreased and then increased, and that at 10-20 cm layer decreased with the increase of the available burrow density. The soil N:P at 0-10 cm layer was similar and that at 10-20 cm layer increased gradually in the increasing process of available burrow density. This study suggested that the correlation relationship between leaf N, P, N:P and soil N, P, N:P was regulated by distribution features of plant root systems and microhabitat where plants grow.