南京林业大学学报(自然科学版) ›› 2024, Vol. 48 ›› Issue (5): 28-38.doi: 10.12302/j.issn.1000-2006.202208030

所属专题: 专题报道:自然保护地森林生态系统研究

• 专题报道:自然保护地森林生态系统研究 • 上一篇    下一篇

雅长保护区老龄林不同林层功能性状多样性及其影响因素分析

王耀仪(), 王宏翔*(), 王永强, 曾文豪, 叶绍明   

  1. 广西大学林学院,广西森林生态与保育重点实验室,广西 南宁 530004
  • 收稿日期:2022-08-13 修回日期:2022-09-19 出版日期:2024-09-30 发布日期:2024-10-03
  • 通讯作者: * 王宏翔 (wanghongxiang168@126.com),讲师。
  • 作者简介:

    王耀仪 (1693843668@qq.com)。

  • 基金资助:
    广西科技基地和人才专项(AD20297051);国家自然科学基金项目(32101520)

Affecting factors analysis of functional diversity at different forest strata in an old growth forest community in Yachang Natural Reserve

WANG Yaoyi(), WANG Hongxiang*(), WANG Yongqiang, ZENG Wenhao, YE Shaoming   

  1. College of Forestry, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning 530004, China
  • Received:2022-08-13 Revised:2022-09-19 Online:2024-09-30 Published:2024-10-03

摘要:

【目的】功能性状多样性对森林生物多样性保护及生态系统功能稳定性的维持具有重要意义。探究不同林层的功能多样性特征及其形成原因,有助于深入理解生物多样性维持机制和植物群落构建过程。【方法】以广西雅长兰科植物国家级自然保护区1.6 hm2常绿阔叶天然老龄林监测样地植被调查数据为基础,运用K-means非层次聚类与高斯核密度估计方法划分林层,采集植物叶片性状和环境因子数据,通过结构方程模型揭示不同林层物种多样性与环境因子(地形、土壤和光照)对功能多样性的直接、间接影响。【结果】①林下层多样性指数显著高于林冠层(P<0.05)。②林下层物种多样性对4个功能多样性指数均有显著的直接影响,而林冠层物种多样性仅对功能丰富度指数(FRic)与功能二次熵指数(RAOQ)有显著的直接影响(P<0.05)。③林冠开度对林下层FRic指数有极显著的间接效应(β= 0.278,P<0.01),对林下层功能均匀度指数(FEve)有极显著的直接效应(β= -0.593,P<0.01)。④地形因子主要影响林冠层功能多样性。其中,坡向对林冠层FEve指数(β= -0.420,P<0.01)与RAOQ指数(β= -0.300,P<0.05)均有显著的直接效应。⑤土壤因子主要通过物种多样性间接影响各林层的功能多样性。其中,林下层功能多样性主要受全磷、有效磷、碱解氮、有效钾含量的影响,而全钾含量对林冠层FRic与RAOQ指数有一定的影响。【结论】研究区内各林层功能多样性存在较大差异。林下层功能多样性主要受物种多样性、林冠开度和土壤养分的影响,而地形因子则是林冠层功能多样性的主要影响因素。本研究结果揭示了不同林层内功能性状多样性对生物及非生物环境变化的响应,拓展了以往对于林分垂直分层多样性的认识,为天然林生物多样性保护提供更进一步的参考依据。

关键词: 老龄林, 林冠层, 林下层, 功能性状多样性, 结构方程模型(SEM)

Abstract:

【Objective】 Functional diversity is crucial for forest biodiversity protection and maintenance of ecosystem stability. Exploring the characteristics and causes of functional diversity variation at different stratum levels will assist in understanding the maintenance mechanisms of biodiversity and plant community assembly processes. 【Method】 Leaf traits and environmental factors were collected from forest plot data from an 1.6 hm2 evergreen broadleaved forest in Guangxi Yachang Orchidaceae National Natural Reserve. K-means partitioning and Gaussian kernel density estimation were used for stratification. The direct and indirect effects of species diversity and environmental factors (light, topography, and soil) on functional diversity were explored in different forest strata using structural equation models. 【Result】 The diversity indices of the understory were greater than those of the canopy (P<0.05). Species diversity had a significant direct impact on all four functional diversity indices in the understory layer, whereas only the functional richness index (FRic) and quadratic entropy (RAOQ) indices were affected directly by species diversity in the canopy layer (P<0.05). A significant indirect effect (β = 0.278, P<0.01) of canopy openness on FRic index and a direct effect (β = -0.593, P<0.01) of canopy openness on functional evenness index (FEve) were found for understory trees. Topographic factors affected canopy functional diversity. Specifically, there was a relatively significant direct effect of aspect on FEve (β = -0.420, P<0.01) and RAOQ (β = -0.300, P<0.05) indices for canopy trees. Soil factors mainly affected the functional diversity of different forest layers through species diversity. Soil total phosphorus, available phosphorus, alkaline hydrolysis nitrogen, and available potassium content had a greater effect on the functional diversity of the understory, whereas soil total potassium content affected the FRic and RAOQ indices of the canopy. 【Conclusion】 There were marked differences in the characteristics of functional diversity at different forest stratum in the study area. Functional diversity was mainly affected by species diversity, canopy openness, and soil nutrients of understory plants, whereas topographic factors determined the functional diversity of the canopy layer. This study reveals the effects of biological and abiotic environmental factors on functional diversity across different forest layers and expands the understanding of the diversity of vertical stratification. The findings provide a further reference for biodiversity protection in natural forests.

Key words: old-growth forest, canopy, understory, functional diversity, structural equation model (SEM)

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