植物生态学报 ›› 2013, Vol. 37 ›› Issue (5): 373-383.DOI: 10.3724/SP.J.1258.2013.00039

• 研究论文 •    下一篇

山西灵空山小蛇沟林下草本层植物群落梯度分析及环境解释

余敏1,周志勇1,康峰峰1,欧阳帅1,米湘成2,孙建新1,*()   

  1. 1北京林业大学森林培育与保护教育部重点实验室, 北京 100083
    2中国科学院植物研究所环境与植被变化国家重点实验室, 北京 100093
  • 发布日期:2013-05-16
  • 通讯作者: 孙建新
  • 基金资助:
    国家林业局林业公益性行业科研专项(200804001);北京市教育委员会科学研究与科研基地建设项目(省部共建重点实验室—— 森林培育与保护教育部重点实验室)

Gradient analysis and environmental interpretation of understory herb-layer communities in Xiaoshegou of Lingkong Mountain, Shanxi, China

YU Min1,ZHOU Zhi-Yong1,KANG Feng-Feng1,OUYANG Shuai1,MI Xiang-Cheng2,SUN Jian-Xin1,*()   

  1. 1Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China
    2State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • Published:2013-05-16
  • Contact: SUN Jian-Xin

摘要:

通过对山西灵空山小蛇沟集水区的林下草本层植物群落进行调查和多元分析——TWINSPAN分类、典范对应分析(CCA)与生境、生物因素变量分离, 探讨林分水平上草本层物种分布与环境因子之间的关系。结果如下: 1) TWINSPAN将26个调查样方划分为6种群落类型: 以辽东栎(Quercus wutaishanica)为主的辽东栎-油松(Pinus tabulaeformis)林型、辽东栎杂木林型、辽东栎林型、华北落叶松(Larix principis-rupprechtii)林型、油松林和阔叶油松林型、油松-辽东栎均匀混交林型, 体现了该地区地带性植被类型为暖温带森林的特点。2)群落类型的划分与CCA的结果相吻合, 主要反映了CCA排序第一、二轴的环境梯度, CCA排序轴第一轴突出反映了林分类型与土壤养分梯度, 第二排序轴与坡度、坡位显著相关。Monte Carlo检验结果表明, 林分类型、土壤养分和坡度是影响小蛇沟集水区内林下草本物种分异的最主要的环境因子。3)生境因子与生物因子解释了物种格局变化的42.9%, 其中生境因子占31.8%, 生物因子占7.9%, 生境因子与生物因子交互作用解释部分占3.2%。良好的环境解释反映了调查取样和环境因子选取的合理性。对于50%以上未能被解释的变异部分, 可能归咎于未被选取的因子如干扰或者随机过程。4)在海拔梯度较小的山区, 坡向等小地形因子能较好地指示局部生境的小气候条件, 对林下植物的分布有较好的解释力。

关键词: 典范对应分析(CCA), 暖温带森林, 林下群落, 地形, 变量分离, 植被-环境关系

Abstract:

Aims Many past practices in afforestation and forest management were instrumented for addressing the issues of tree species selection, planting regimes and development of overstory structure, but neglected understory vegetation. Our objective was to determine the controlling factors of herb-layer plant distribution and the importance of topography in determining local-scale spatial patterns of herbaceous plants.
Methods The occurrence and distribution of herb-layer plants were investigated on 26 plots in the Xiaoshegou catchment of Lingkong Mountain, Shanxi Province, China. Community types were classified using two-way indicator species analysis (TWINSPAN) and the relationship between the distribution and abundance of herb-layer species and environmental gradients was analyzed using the canonical correspondence analysis (CCA) ordination method. Forward selection and Monte Carlo permutation test were used to select the factors important in determining the herb-layer plant distribution. Partial CCA (PCCA) was also performed to partition the variance that was explainable by categorical habitat and biotic factors studied.
Important findings The 26 survey plots were classified into six groups characterized by the dominant overstory tree species. The results of CCA ordination reflected the relationship between herb-layer community structure and selective environmental variables. The classification of 26 plots in CCA ordination was consistent with the result of TWINSPAN. Forward selection and Monte Carlo test suggested that stand type, soil nutrients and slope position were the most important factors determining understory plant distribution. PCCA revealed that habitat and biotic factors together explained 42.9% of variance in the distribution of understory herbaceous plants. Habitat factors alone explained 31.8% of the variance, biotic factors alone explained 7.8% of the variance and interaction between habitat and biotic factors explained 3.2% of the variance. The partitioning of variance using the PCCA helped with identifying the important habitat factors regulating understory herbaceous plant distribution at the study site. However, the fact that more than half of the variance was unaccounted for by the factors studied suggests that other factors we did not measure could also play a role in determining the occurrence and distribution of herbaceous plants on the forest floor, e.g., human activities and random events. Our study demonstrates the importance of both topography and overstory tree species in determining the occurrence and distribution of herb-layer plant species in temperate forest of mountainous areas.

Key words: canonical correspondence analysis (CCA), temperate forest, understory communities, topography, variance partitioning, vegetation-site relationship