生物多样性 ›› 2022, Vol. 30 ›› Issue (2): 21419.  DOI: 10.17520/biods.2021419

所属专题: 物种形成与系统进化

• 研究报告: 植物多样性 • 上一篇    下一篇

干旱内陆河流域植物群落构建过程及其关键驱动因素

王寅1,2, 王健铭1,2, 曲梦君1,2, 李景文1,2,*()   

  1. 1.北京林业大学生态与自然保护学院, 北京 100083
    2.北京林业大学额济纳胡杨研究所, 内蒙古阿拉善盟 735400
  • 收稿日期:2021-10-21 接受日期:2021-11-18 出版日期:2022-02-20 发布日期:2022-02-28
  • 通讯作者: 李景文
  • 基金资助:
    国家自然科学基金(31971538);国家自然科学基金(31570610)

Plant community assembly processes and key drivers in an arid inland river basin

Yin Wang1,2, Jianming Wang1,2, Mengjun Qu1,2, Jingwen Li1,2,*()   

  1. 1 School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083
    2 Ejina Institute of Populus euphratica, Beijing Forestry University, Alxa, Inner Mongolia 735400
  • Received:2021-10-21 Accepted:2021-11-18 Online:2022-02-20 Published:2022-02-28
  • Contact: Jingwen Li
  • About author:*E-mail: Lijingwenhy@bjfu.edu.cn

摘要:

作为干旱内陆河流域水资源可利用性的决定性因素之一, 地下水位在调节植物功能性状、系统发育乃至植物群落构建方面发挥着至关重要的作用。然而地下水位变化对干旱内陆河流域植物群落构建过程相对重要性的影响, 以及这种影响在地上-地下组分间的差异尚未得到系统研究。本文以典型干旱内陆河流域下游的主要植物群落为研究对象, 结合叶片、根系功能性状与环境数据, 系统地探讨植物群落构建过程沿地下水位梯度的变化模式及其关键驱动因素。结果表明: (1)综合植物个体、平均功能性状和系统发育可知, 在整个研究区域, 叶片、根系功能多样性的标准效应值(SES.RaoQ)均小于0。大多数植物群落的功能结构(90%的功能性状)表现为聚集状态。(2)地下水与土壤因子共同解释叶片、根系SES.RaoQ 13%-39%与14%-48%的变异, 而地下水位能够单独解释叶片、根系SES.RaoQ 13%-22%与14%-36%的变异。(3)叶片、根系SES.RaoQ均随平均地下水位的降低而降低, 随地下水位季节性的增加而增加; 根系SES.RaoQ与地下水位的斜率大于叶片SES.RaoQ。总体而言, 干旱内陆河流域植物群落的构建机制整体上由确定性过程主导, 支持生态位理论, 大多数植物群落的构建机制符合生态位理论中的环境筛选作用。地下水位是调控不同群落构建过程相对重要性的主要因素, 随地下水位的降低, 功能结构由发散状态转为聚集状态。植物群落地上、地下功能结构沿地下水位梯度的变化表现出一致性, 但植物群落地下部分对地下水位的变化更为敏感。

关键词: 群落构建, 叶片, 根系, 地下水位, 干旱内陆河流域

Abstract

Aims One of the determinants of water availability in drylands, groundwater plays a fundamental role in regulating plant traits, phylogeny, and community assemblage. However, considerable uncertainties exist regarding how groundwater depth influences the relative importance of community assembly process in plant communities, as well as how the influence differs among the above- and belowground components.

Methods By using the leaf and root functional traits, in addition to associated environmental factors in 230 plant communities in the lower reaches of an arid inland river basin, we attempted to uncover how the pattern of the community assembly process varied along a depth gradient of groundwater and the key drivers of this variation.

Results (1) Across all study sites, we found that the standard effect size of Rao’s quadratic entropy (SES.RaoQ) of leaf and root functional diversity determined using the plant individual species, mean functional traits and phylogenetic information was significantly less than zero. Functional clustering was pervasive among plant communities (90% of the traits). (2) Groundwater depth and soil variables together explained 13%-39% and 14%-48% of the variation in SES.RaoQ determined using leaf and root traits, respectively, and groundwater depth individually explained 13%-22% and 14%-36% of the variation. (3) The SES.RaoQ determined using leaf and root traits decreased as mean groundwater depth decreased, but it increased with increased groundwater depth seasonality. Root traits showed a faster shift in SES.RaoQ along groundwater depth gradients than leaf traits.

Conclusion Plant communities in an arid inland river basin are primarily affected by deterministic processes, which supports the niche theory. Most plant communities exhibited functional clustering. Groundwater depth is the key factor determining the relative importance of the community assembly process of plant communities. With the decrease of groundwater depths, the functional structure changes from a pattern of mostly overdispersion to a pattern of clustering. The variation in aboveground functional structure along groundwater gradients is highly consistent with that of the belowground functional structure, but the belowground component of plant communities may be more sensitive to changes in groundwater depth.

Key words: community assembly, leaf, root, groundwater depth, arid inland river basin