青藏高原东北缘高寒草甸珠芽蓼斑块植被构成和种间关联

The vegetation composition and interspecific association of patches distributing in Polygonum viviparum alpine meadow on northeast Qinghai-Tibetan Plateau

群落植物种构成和种间关系反映植物种群和群落分布格局上的互作关系。通过对珠芽蓼(Polygonum viviparum)斑块及其对照区域群落植物种重要值、物种多样性指数、生物量构成及植物种种间关联Jaccard指数和Spearman秩相关进行分析,揭示高寒草甸演替过程中的生态学机制。结果表明,珠芽蓼斑块的样方物种数显著高于对照(P<0.05),二者类群生物量与其重要值构成变化规律类似。珠芽蓼斑块的植被构成以杂类草和禾草为主,其占绿色生物量的60.9%和22.1%,且珠芽蓼种群约占绿色生物量的1/3;而对照则以禾草和杂类草为主,分别占绿色生物量的53.3%和27.1%。珠芽蓼斑块及对照群落中,显著关联的种对数分别占各自总种对数的16.4%和33.0%,多数植物种对的种间联结较松散,种对间独立性较强,二者正相关与负相关种对数比分别为0.83和1.40。珠芽蓼斑块群落处于稳定阶段,珠芽蓼斑块的形成,能增强高寒草甸的群落稳定性。

The vegetation composition and interspecific relationship reflect the interaction relationship of spatial distribution pattern among plant populations and communities. We analyzed the important value, diversity index of species, biomass composition, the Jaccard association index and spearman rank correlation coefficient of main species growing on patch in Polygonum viviparum alpine meadow （P. viviparum patch） and control （CK）, in order to reveal the ecological mechanism of succession process in Alpine meadow. The results indicated that number of species in P. viviparum patch was bigeer than that in CK, and the change pattern of each group was similar between important value and biomass composition. P. viviparurn patch dominated mainly by forbs and grasses, accounting for 60.9% and 22.1% of the green biomass, respectively, and P. viviparum accounted for about one third of the green biomass; while it dominated mainly by grasses and forbs, accounting for 53.3% and 27.1% of the green biomass, respectively. In P. viviparurn patch and CK, the significantly associated species-pairs accounted for 16.4% and 33.0% of their respective total species-pairs. The interspecific association of most species-pairs was not significant, and the independence between species-pairs was stronger. The ratios of negative and positive correlations were 0.83 and 1.40, respectively. Plant communities of P. viviparum patch was a stable stage. The formation of P. viviparum patch can strengthen community stable of alpine meadow.