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基于SEM解析科尔沁沙地生境条件对植物群落的直接和间接影响

曹文梅,刘廷玺*,王冠丽,罗艳云,付青云   

  1. (内蒙古农业大学水利与土木建筑工程学院, 内蒙古自治区水资源保护与利用重点实验室, 呼和浩特 010018)
  • 出版日期:2019-04-10 发布日期:2019-04-10

Direct and indirect effects of habitat conditions on plant community in Horqin Sandy Land based on SEM.

CAO Wen-mei, LIU Ting-xi*, WANG Guan-li, LUO Yan-yun, FU Qing-yun   

  1. (Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region Water Resource Protection and Utilization Key Laboratory, Hohhot 010018, China).
  • Online:2019-04-10 Published:2019-04-10

摘要: 由于生态系统的复杂多样性,量化生境条件对植物群落形成及演替的影响是生态学研究中的难点。本文以位于西辽河流域东南位置的科尔沁沙地为研究对象,收集55个湿草甸斑块样品和278个沙丘斑块样品,在湿草甸沙丘组合斑块和单一的沙丘斑块两种不同研究尺度下,利用混合型结构方程构建了能反映生境条件对植被群落直接和间接影响关系的模型,并采用偏最小二乘法对结构方程进行分析。结果表明:在湿草甸沙丘组合斑块中,对于显著影响植被群落的直接因素,影响效果由大到小依次是土壤结构性能、土壤含水量和地下水位埋深,路径系数分别为0.607、0.230和-0.224;在单一的沙丘斑块中,对于显著影响植被群落的直接因素,影响效果由大到小依次是土壤结构性能、土壤含水量和土壤有机质(SOM)含量,路径系数分别为0.399、0.224和0.206;对比两种尺度的模拟结果可看出,当地下水位埋深对植物群落的直接效应显著时,会使SOM含量对植物群的直接影响效应变得不显著,但仍然可以通过影响土壤结构间接影响植物群落;坡度和高程对土壤质量的直接影响效应在两种尺度下是相反的,坡向的影响效果不显著;通过在结构方程模型中构建一个区域植被群落格局的形成型潜变量可以推断该区域植被演替的动态过程。

关键词: 生态类群, 山毛榉林, 土壤螨类, 喀斯特, 群落多样性

Abstract: Due to the complexity and diversity of ecosystems, it is difficult to quantify the impacts of habitat conditions on the formation and succession of plant community. Here, we collected samples from 55 patches of wet meadow and from 278 patches of sand dune from Horqin Sandy Land located in the southeast of the West Liaohe River Basin. The relationships between plant communities and habitat conditions at different scales (wet meadowsand combination patches and individual sand dune patches) were evaluated by a mixed structural equation model, with the structural equation being analyzed by the partial least square method. In the wet meadowsand combination patches, the direct factors with significant effects on plant communities were soil structure, soil water content, and groundwater depth sorted by effect size, with the path coefficients of 0.607, 0.230, and -0.224, respectively. In the individual sand dune patches, thedirect factors with significant effects on plant communities were soil structure, soil water content, and soil organic matter (SOM) content sorted by effect size, with the path coefficients of 0.399, 0.224, and 0.206, respectively. When the direct effect of groundwater depth on plant community was significant, the direct effect of SOM content on plant community was insignificant, but with indirect effects on plant community indirectly by affecting soil structure. The direct effects of slope and elevation on soil quality were opposite at both scales, and the effect of slope direction was not significant. By constructing a latent variable of vegetation pattern in the structural equationmodel, we can infer the dynamics of community succession in the study area.

Key words: karst, beech, ecological group, soil mites, community diversity