敦煌阳关盐沼湿地芦苇种群小尺度空间分布格局

植物种群的空间分布格局是研究连接植物与外界环境关系的重要桥梁,是植物种群稳定性和生活史策略的表现形式。本研究以敦煌阳关盐沼湿地克隆植物芦苇(Phragmites australis)为对象,设置湿生区、轻度盐化区、重度盐化区和荒漠区采样梯度,应用Ripley K(d)函数分析法研究了芦苇种群的小尺度空间分布格局特征及生态适应对策。结果表明:(1)随着从湿生到荒漠区环境梯度的变化,芦苇种群的盖度、密度、高度、地上生物量及种群领地面积都呈现出显著下降的趋势,空斑面积呈现出显著增加的趋势,而种群领地密度则呈现出先增加后下降的趋势;(2)从湿生到荒漠生境,芦苇种群的小尺度空间拓展策略主要表现为由聚集分布为主、非聚集分布(随机分布或均匀分布)为辅,转变为随机分布为主、非随机分布(聚集分布或均匀分布)为辅的特征。研究结果明晰了干旱区内陆河湿地中芦苇种群的空间分布格局特点及其影响因素,为进一步理解克隆植物的生态适应机制提供了案例研究,为科学保护和管理干旱区内陆河湿地生态系统提供了理论依据。

Fine-scale spatial pattern of Phragmites australis population in salt marshes of Yangguan,Dunhuang

The spatial pattern of plant population is a key to study the relationship between plants and environment.It is a manifestation of the stability and life history strategies of plant population.To clarify fine-scale spatial pattern of Phragmites australis population in salt marsh of Yangguan,Dunhuang,we investigated their populations in four different sites across a gradient of wet zone,light salt zone,heavy salt zone,and desert zone.The Ripley K(d)function analysis method was used to examine the fine-scale spatial pattern of P.australis populations and its ecological adaptation.The results showed that,from wetland to desert,the coverage,density,height,and above-ground biomass of P.saustralis showed a significant downward trend.The gap size significantly increased,while population density increased initially and then decreased.Across the gradient,the strategies of spatial expansion for P.australis population were changed from the clumped distribution as the main type,non-clumped distribution(random or regular distribution)as the supplement,to the random distribution as the main type and non-random distribution(clumped or regular distribution)as the supplement.Our results clarified the spatial pattern and driving factors of P.australis population in the inland riverine wetland,and served as a case study for further understanding ecological adaptation mechanism of clonal plants,and theoretical basis for scientific conservation and management of the inland riverine wetlands in the arid region.