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生态学杂志 ›› 2023, Vol. 42 ›› Issue (5): 1049-1055.doi: 10.13292/j.1000-4890.202305.023

• 研究报告 • 上一篇    下一篇

海拔和林分密度对热带雨林林下植物多样性的影响

姜祖扬1,覃业辉1,刘季1,文志2*,郑华2,3,欧阳志云2


  

  1. 1海南热带雨林国家公园管理局鹦哥岭分局, 海南白沙 572800; 2中国科学院生态环境研究中心城市与区域生态国家重点实验室, 北京 100085; 3中国科学院大学, 北京 100049)

  • 出版日期:2023-05-10 发布日期:2023-05-05

Effects of altitude and stand density on understory plant diversity in tropical rainforests.

JIANG Zuyang1, QIN Yehui1, LIU Ji1, WEN Zhi2*, ZHENG Hua2,3, OUYANG Zhiyun2   

  1. (1Yinggeling Branch Office, National Park of Hainan Tropical Rainforest, Baisha 572800, Hainan, China; 2State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; 3University of Chinese Academy of Sciences, Beijing 100049, China).

  • Online:2023-05-10 Published:2023-05-05

摘要: 海拔和林分密度是影响生物多样性的重要因子,但目前对热带雨林中海拔和林分密度复合影响林下植物多样性的效应及路径研究仍不足。本研究在海南热带雨林中基于海拔和林分密度设置了32个样地,调查了各样地植物特征,分析了海拔和林分密度对林下植物多样性(物种丰富度、Shannon多样性指数、Simpson优势度指数和物种均匀度)的影响,探索了两者直接或间接通过林分上层植物多样性和环境因子(郁闭度、凋落物、土壤C/N、土壤N/P和土壤pH)的影响路径。结果表明:海拔升高对林下物种丰富度、Simpson优势度和均匀度影响不大,但显著降低林下Shannon多样性,其主要通过改变林分上层Shannon多样性和郁闭度发挥间接调节效应;与之相比,林分密度增加显著降低林下物种丰富度,其既可通过增加郁闭度和土壤N/P产生间接影响,还可产生直接负效应。本研究证实了热带雨林中海拔和林分密度变化对林下植物多样性影响的不同,明确了郁闭度是两者复合调控林下植物多样性的重要因子,加深了林下植物多样性形成机制的认识。

关键词: 植株密度, 生物多样性, 林下植被, 热带山地雨林

Abstract: Altitude and stand density are important factors affecting biodiversity, but the compound effects and pathways of altitude and stand density affecting understory plant diversity in tropical rainforests are largely unknown. In this study, we set up 32 plots based on elevation and stand density gradients in tropical rainforests located in Hainan Island, China. We surveyed plant species diversity in each plot and analyzed the influence of altitude and stand density on understory plant diversity (species richness, Shannon diversity index, Simpson dominance index, and species evenness). The pathways by which altitude and stand density affect understory plant diversity directly or indirectly through overstory plant diversity and environmental factors (canopy closure, litter, soil C/N, soil N/P, and soil pH) were explored. The results showed that altitude had limited effect on understory species richness, Simpson dominance index, and species evenness, but significantly reduced Shannon diversity index indirectly via overstory Shannon diversity and canopy density. Compared with altitude, increases of stand density significantly reduced the understory species richness, directly and indirectly by increasing canopy density and soil N/P. Our results highlight the difference in the effects of altitude and stand density on understory plant diversity, and show that canopy density is an important factor for the combined effects on understory plant diversity. Our findings deepen the understanding of the formation mechanism of understory plant diversity in tropical rainforests.


Key words: plant density, biodiversity, understory vegetation, tropical mountain rainforest.