祁连山北坡草地植物群落特征与土壤水热因子的关系

The relationship of characteristics of meadow communities with soil moisture and temperature in the northern slope of Qilian Mountains

环境因子对草地生态系统的结构和功能有重要影响。通过野外调查和室内实验,研究了祁连山北坡草地植物群落的物种多样性和地上生物量变化,并对地上生物量与土壤水热因子的关系进行了探讨。结果表明：5—9月,不同草地植物群落的丰富度、多样性、均匀度变化均表现为单峰曲线,不同草地植物群落之间丰富度和多样性差异显著,而均匀度在5、7、9月差异不显著;山地草甸草原与山地草原的物种中等不相似,其他草地植物群落的物种极不相似,不同草地植物群落沿海拔替代明显;5—9月,不同草地植物群落的地上生物量均为单峰曲线,山地草甸和山地荒漠草原的地上生物量在7月最大,而山地草甸草原和山地草原的地上生物量在8月最大;不同草地植物群落地上生物量的积累与当月0~10cm的地温明显正相关,而与当月土壤水分不相关。

Environmental factors play key roles in structure and function of grassland ecosystems.This paper analyzed the variation of species diversity and aboveground biomass of meadow communities,and the relationship between aboveground biomass and soil moisture / temperature through field investigation and laboratory analysis in the northern slope of Qilian Mountains during the growing season in 2013. The results indicated that single peaks were found in species richness,diversity and evenness from May to September. Among different meadow communities,significant differences were found in species richness and diversity,but not recorded in species evenness in May,July and September. The species between meadow steppe and upland steppe were moderately dissimilar,but those were extremely dissimilar among different meadow communities,reflecting the obvious replace of different types of plant communities along the elevation.The variations of aboveground biomasses for different meadow communities displayed a single peak in July for alpine meadow and desert steppe,and in August for meadow steppe and upland steppe. In different meadow communities,the accumulations of aboveground biomasses were positively related to soil temperature under 0-10 cm,while were not related to soil moisture.