放牧干扰下若尔盖高原沼泽湿地植被种类组成及演替模式  

Species composition and succession of swamp vegetation along grazing gradients in the Zoige Plateau,China

作　　者：韩大勇[1] 杨永兴[1] 杨杨[2] 李珂[1] 

机构地区：[1]同济大学环境科学与工程学院污染控制与资源化国家重点实验室长江水环境教育部重点实验室,上海200092 [2]同济大学生命科学与技术学院,上海200092

出　　处：《生态学报》2011年第20期5946-5955,共10页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(40771013;41171074;U0933601;40971285);2004年上海市科学技术委员会重大攻关项目(04DZ19302)

摘　　要：以若尔盖高原退化沼泽植被为研究对象,应用多重比较、双因素方差分析、物种累积曲线、PCA排序、方差分解等方法分析了不同放牧压力、放牧季节下物种丰富度、多度、生活型组成、群落演替的变化。结果表明:不同放牧季节物种丰富度格局不尽相同,其中6、9、10月在各牧压梯度间无显著差异,7、8月均以极重度和极度阶段(中生草甸)的最高,原生沼泽的最低。在物种累积速率上,沿牧压梯度以极重度和极度阶段的最高,沿放牧季节以7、8月最高;双因素方差分析结果进一步表明物种丰富度与放牧季节无显著关系,但与放牧压力关系显著。放牧压力和放牧季节共解释了物种多度总方差的47.6%,其中放牧压力解释了50.1%,放牧季节以及二者方差交集均为负值;沿牧压梯度,沼泽植被逆向演替模式倾向于沼泽→草甸,沼泽化草甸阶段不明显,但是演替方向未发生变化,建群种替代规律为:乌拉草→木里苔草→栗褐苔草,生活型组成中直立型植物比例较少,莲座型和匍匐型植物增加。总之,放牧季节对物种丰富度无显著影响,但在一定程度上改变了其牧压梯度格局,降低了物种累积速率。放牧压力改变了群落物种丰富度、生活型组成和演替模式,但放牧可能仅为沼泽植物群落物种多样性格局和演替的驱动力之一。Grazing is the most common forms of human disturbance that caused the degradation of swamp vegetation.In the past decades,there were few studied on vegetation changes under the combined impact of grazing season and intensity.In this study,six plots were selected along grazing gradients based on the distance to settlement in a degraded swamp.The field survey were conducted from the beginning（1st June） to the end（31th October） across entirely growing season.Duncan′s multiple comparison,univariate GLM analysis,species accumulation curves,PCA ordination and variance partitioning were employed to analyze the plant species richness and abundance,life form and plant community succession in the process of swamp vegetation degradation.The results showed that： A total of 46 vascular plant species across all seasons and plots were recorded.There were no significant difference between the spatial patterns of mean species richness within single sample across grazing gradients in June,September and October,and the mean species richness within single sample was highest in extreme and severe degradation stages and lowest in pristine swamp in July and August.The rates of species accumulation were highest in extreme and severe degradation stages along grazing gradients and highest in July and August along grazing season.The mean species richness within single sample had no significant correlation to grazing season,but had significant correlation to grazing pressure.The variance partitioning results indicated that the variation of species abundance with grazing intensity is much higher than that with grazing season,the variation explained by grazing intensity was 50.1%,explained by season and intersection were all negative.The total variation explained by grazing intensity and season was 47.6%.The mode of regressive succession tended to swamp→meadow and the transitory stage,namely swamp meadow,was atypical.The succession of constructive species followed the order of Carex meyerianaa→C.muliensis→C.brunea,but the di

关 键 词：放牧 物种丰富度 群落演替 生活型 若尔盖高原沼泽 

分 类 号：Q948[生物学—植物学]