植物生态学报 ›› 2020, Vol. 44 ›› Issue (1): 33-43.doi: 10.17521/cjpe.2019.0283

• 研究论文 • 上一篇    下一篇

小叶锦鸡儿灌丛化对典型草原群落结构与生态系统功能的影响

丁威1,王玉冰2,3,向官海2,3,迟永刚4,鲁顺保1,*(),郑淑霞2,*()   

  1. 1江西师范大学生命科学学院, 南昌 330022
    2中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
    3中国科学院大学, 北京 100049
    4浙江师范大学地理与环境科学学院, 浙江金华 321004
  • 收稿日期:2019-10-22 修回日期:2020-01-14 出版日期:2020-01-20 发布日期:2020-03-26
  • 通讯作者: 鲁顺保,郑淑霞 E-mail:luxunbao8012@126.com;zsx@ibcas.ac.cn
  • 基金资助:
    国家重点研发计划(2016YFC0500801);国家自然科学基金(41671046);国家自然科学基金(31400393)

Effects of Caragana microphylla encroachment on community structure and ecosystem function of a typical steppe

DING Wei1,WANG Yu-Bing2,3,XIANG Guan-Hai2,3,CHI Yong-Gang4,LU Shun-Bao1,*(),ZHENG Shu-Xia2,*()   

  1. 1College of Life Sciences, Jiangxi Normal University, Nanchang 330022, China
    2State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    3University of Chinese Academy of Sciences, Beijing 100049, China
    4College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
  • Received:2019-10-22 Revised:2020-01-14 Online:2020-01-20 Published:2020-03-26
  • Contact: LU Shun-Bao,ZHENG Shu-Xia E-mail:luxunbao8012@126.com;zsx@ibcas.ac.cn
  • Supported by:
    National Key R&D Program of China(2016YFC0500801);National Natural Science Foundation of China(41671046);National Natural Science Foundation of China(31400393)

摘要:

草原灌丛化是全球干旱半干旱地区面临的重要生态问题。灌丛化对草原生态系统结构与功能的影响较为复杂, 有待于在更广泛的区域开展研究。该研究在内蒙古锡林郭勒典型草原选择轻度、中度和重度灌丛化草地, 通过群落调查, 结合植物功能性状和土壤理化性质观测, 研究了小叶锦鸡儿(Caragana microphylla)灌丛化对草原群落结构(物种多样性、功能多样性和功能群组成)和生态系统功能(初级生产力、植被和土壤养分库)的影响。结果表明: 1)不同程度灌丛化草地的物种丰富度、功能性状多样性和群落加权性状平均值差异显著, 其中, 中度灌丛化草地的物种多样性和功能多样性较高, 表明一定程度的灌丛化有利于生物多样性维持。2)重度灌丛化草地的地上净初级生产力(ANPP)显著高于轻度和中度灌丛化草地, 其原因主要是随着灌丛化程度加剧, 群落内一/二年生草本植物显著增加, 而多年生禾草和多年生杂类草显著减少。三个灌丛化草地的植被叶片和土壤碳、氮库差异均不显著。3)灌丛化对草原生态系统功能包括ANPP、植被和土壤养分库均没有直接的影响, 而是通过影响功能群组成、土壤理化性质和功能多样性, 间接地影响生态系统功能; 灌丛化导致功能群发生替代和土壤旱碱化是最重要的生物和非生物因素。

关键词: 灌丛化, 物种多样性, 功能多样性, 植物功能性状, 功能群组成, 生态系统功能

Abstract:
Aims Shrub encroachment is a critical ecological problem in arid and semi-arid ecosystems worldwide. The effects of shrub encroachment on ecosystem structure and function of grasslands are complicated and need to be explored in future studies. Our objective is to examine the effects and pathways of shrub encroachment on ecosystem structure and function in a typical steppe of the Inner Mongolia grassland.
Methods Three grassland sites with different degrees of shrub encroachment (i.e. light, moderate, heavy) were selected in the Xilingol Nei Mongol, of which Caragana microphylla was the dominant shrub. Species richness and composition, aboveground net primary productivity (ANPP), soil property, and plant functional traits of dominant species were determined in this study. In addition, species diversity, functional attribute diversity, community-weighted mean traits, and vegetation leaf and soil carbon and nitrogen pools were further calculated.
Important findings 1) The species richness, functional attribute diversity and community-weighted mean traits differed significantly among three grassland sites, and species diversity and functional diversity were relatively higher in the moderate shrub-encroachment site, indicating moderate shrub-encroachment favors biodiversity maintenance. 2) The aboveground net primary productivity of heavy shrub-encroachment grassland was significantly higher than those of light and moderate shrub-encroachment grasslands, which was mainly due to a shift in functional group composition, that is, the proportion of annuals and biennials to perennial grasses and forbs increased greatly with intensifying shrub encroachment. The vegetation leaf and soil carbon and nitrogen pools differed little among three sites. 3) Shrub encroachment did not directly affect ecosystem function, including ANPP, vegetation and soil nutrient pools, but it indirectly affected them through pathways of the shift in functional group composition and changes in soil property and functional diversity. Particularly, the shift in functional group composition and intensified soil drought and basification was separately important biotic and abiotic factors for variations in ecosystem function.

Key words: shrub encroachment, species diversity, functional diversity, plant functional trait, functional group composition, ecosystem function