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草业学报 ›› 2025, Vol. 34 ›› Issue (12): 62-72.DOI: 10.11686/cyxb2025021

• 研究论文 • 上一篇    下一篇

围封改变了羌塘草原植物群落多样性和地上生物量间的关系

刘晨旭1(), 宋彦涛1(), 孙磊2, 彭滔1, 乌云娜1   

  1. 1.大连民族大学环境与资源学院,辽宁 大连116000
    2.西藏农牧学院动物科学学院,西藏 林芝 860000
  • 收稿日期:2025-01-20 修回日期:2025-03-17 出版日期:2025-12-20 发布日期:2025-10-20
  • 通讯作者: 宋彦涛
  • 作者简介:E-mail: yantaosong@dlnu.edu.cn
    刘晨旭(1999-),男,河北张家口人,在读硕士。E-mail: 1767911069@qq.com
  • 基金资助:
    大连民族大学-西藏农牧学院联合基金(DLMZ-NMXY2021002);辽宁省科技计划联合计划应用基础研究项目(2023JH2/101700027);中央高校基本科研业务费(2025)资助

Grazing exclusion modifies the relationship between plant community diversity and aboveground biomass in the Qiangtang grassland

Chen-xu LIU1(), Yan-tao SONG1(), Lei SUN2, Tao PENG1, Wuyunna1   

  1. 1.College of Environmental and Bioresources,Dalian Minzu University,Dalian 116000,China
    2.College of Animal Science,Xizang Agriculture Animal Husbandry University,Nyingchi 860000,China
  • Received:2025-01-20 Revised:2025-03-17 Online:2025-12-20 Published:2025-10-20
  • Contact: Yan-tao SONG

摘要:

围封是恢复退化草原生态系统的有效措施之一。为探寻围封对草原植物群落的影响,本研究在那曲市班戈县,以羌塘草原围封区域为研究对象,选取围封5、9、13、17以及21年样地,对照为各围封年限样地围栏外自由放牧样地。通过方差分析、回归分析和相关性分析研究两种土地利用方式对植物群落特征、植物群落多样性以及两者间关系的影响。结果表明:围封增加了优势种紫花针茅的重要值,围封不同年限后地上生物量、盖度、高度和密度均有不同程度的提高,其中在围封9、21年后围栏内显著高于围栏外(P<0.05)。围封9年后,围栏内α多样性指数显著低于围栏外(P<0.05)。并且围封后,地上生物量和植物群落多样性的关系发生改变,围栏外地上生物量和植物群落多样性的关系呈正相关趋势,但并不显著(P>0.05),而围栏内二者的关系呈显著的负相关趋势(P<0.05)。综上所述:羌塘草原围封9年左右是较为合理的时间,而围封后,根据“质量比假说”优势种(紫花针茅)地上生物量的增加是影响地上生物量和植物群落多样性关系的关键因子。

关键词: 围封, 羌塘草原, 植物多样性, 地上生物量, 重要值

Abstract:

Grazing exclusion is one of the effective measures for restoring degraded grassland ecosystems. The aim of this study was to examine the effect of fencing for various periods on grassland plant communities in the Qiangtang grassland. A field study was conducted in Nagqu City, Bangor County, where grassland plots enclosed for 5, 9, 13, 17, and 21 years were selected for analysis, with freely-grazed areas outside the enclosures as the control plots. We assessed the effects of enclosure and free-grazing practices on plant community characteristics, plant community diversity, and their relationships by analysis of variance, regression analysis, and correlation analysis. The results indicate that enclosure increased the importance value of the dominant species, Stipa purpurea. Varying levels of enhancement in aboveground biomass (AGB), coverage, height, and density were observed after different periods of enclosure, with significant differences detected between the free-grazed and enclosed plots after 9 and 21 years (P<0.05). Notably, the alpha diversity of the plant community was significantly lower in enclosed plots than in free-grazed plots after 9 years of enclosure (P<0.05). Following initial grazing exclusion, the relationship between AGB and plant community diversity underwent a pronounced shift. In non-enclosed (grazed) areas, AGB and diversity indices exhibited a positive, albeit non-significant correlation (P>0.05). Conversely, within the enclosures, AGB and diversity indices showed statistically significant negative correlations (P<0.05). These results collectively indicate that enclosure for 9 years optimizes grassland management outcomes for the Qiangtang grassland. Crucially, the post-enclosure increases in the AGB of the dominant species (S. purpurea) serve as the primary mechanistic driver underlying the change in the AGB-diversity relationship, consistent with the mass ratio hypothesis.

Key words: exclosure, Qiangtang grassland, plant diversity, aboveground biomass, importance value