若尔盖高寒沼泽植物群落与环境因子的关系

Relationships between main plant communities and environment in Zoige marsh

了解高寒沼泽植物群落与环境因子之间的关系,对揭示物种对生态环境的需求以及高寒沼泽的保护管理有重要意义,然而目前尚不清楚影响若尔盖高寒沼泽植物分布的主要环境因素。作者于2011—2012年间在若尔盖高寒沼泽随机调查32个样地,收集了植被样方数据、土壤理化性质数据、地表水位等实测数据,借助方差分析、CCA分析和相关分析等经典的统计方法,研究高寒沼泽植物群落物种组成和不同地表积水状况下多样性的差异,以及高寒沼泽植物群落与环境因子的关系。结果显示:若尔盖高寒沼泽植物共有151个种,隶属于39科98属;多样性指数随地表积水的减少呈现出增加的趋势。典范对应分析(CCA)结果表明,第一轴与水位、土壤水分含量、土壤有机碳、土壤总氮显著负相关,与土壤容重显著正相关,第二轴与裸斑率和鼠洞数显著相关。前2个轴一共解释了79.8%的物种与环境因子的关系,与环境因子的相关系数均在0.87以上;其中,水分和土壤养分条件是影响物种分布的主导因子,其次是裸斑面及啮齿动物活动。植物多样性指数与土壤水分负相关,与土壤有机碳和土壤全氮显著负相关,与土壤容重显著正相关。若尔盖沼泽植物群落物种多样性除了受土壤水分和养分条件的影响以外,啮齿动物的活动可能是影响若尔盖沼泽物种分布以及促进群落进一步演替的主要因素之一。

This study focuses on relationships between community diversity and environmental factors as well as the classification ofthe Zoige marsh. Vegetation quadrat data, soil physiochemical properties data, and water table data were collected at 32 sites on the Zoige marsh during July and August in 2011-2012. The plant species composition and the plant diversity differences among different surface water conditions, as well as the relationship between plant communities and environmental factors in Zoige marsh were studied by using analysis of variance, canonical correspondence analysis （CCA）, and correlation analysis. A total of 151 plant species in Zoige marsh belonging to 39 families and 98 genera were identified. Diversity indexes increased basically as the surface water declined. Based on the CCA results, the first two axes explained 79.8% of the variance within the species-environment relationships, and the community distribution was influenced greatly by moisture content and soil nutrient condition, followed by habitat patches and rodent activity. Correlation analysis shows species Richness index and Shannon-Wiener index were in significantly negative correlation with soil water content （SWC）, soil organic carbon （SOC）, total nitrogen （TN）, and surface water level （WT）, but were in significantly positive correlation with soil bulk density. Environmental factors are important determinants of the distribution of native plant species in Zoige marsh.