植物生态学报 ›› 2024, Vol. 48 ›› Issue (12): 1612-1622.DOI: 10.17521/cjpe.2023.0293  cstr: 32100.14.cjpe.2023.0293

• 研究论文 • 上一篇    下一篇

东北天然次生林同种和异种密度制约效应随生活史阶段变化规律

强亚琪, 张新娜, 王娟, 张春雨*()   

  1. 北京林业大学林木资源高效生产全国重点实验室, 北京 100083
  • 收稿日期:2023-10-16 接受日期:2024-04-08 出版日期:2024-12-20 发布日期:2024-12-20
  • 通讯作者: *张春雨(zcy_0520@163.com)
  • 基金资助:
    国家自然科学基金(32371870)

Variation of conspecific and heterospecific density-dependent survival along life stages in natural secondary forests in Northeast China

QIANG Ya-Qi, ZHANG Xin-Na, WANG Juan, ZHANG Chun-Yu*()   

  1. State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing 100083, China
  • Received:2023-10-16 Accepted:2024-04-08 Online:2024-12-20 Published:2024-12-20
  • Contact: *ZHANG Chun-Yu(zcy_0520@163.com)
  • Supported by:
    National Natural Science Foundation of China(32371870)

摘要: 探究温带森林不同生活史阶段是否存在密度制约现象, 及密度制约的相对重要性是否随生活史阶段变化, 可为温带森林局域尺度物种共存提供理论依据。该研究基于对吉林蛟河针阔混交林21.12 hm2固定监测样地中451个幼苗监测样方连续3年(2016-2018)的动态监测以及乔木的复测数据, 运用广义线性混合模型、引入交互作用的广义线性混合模型、引入物种间随机效应和交互作用的广义线性混合模型和单独引入物种间随机效应的广义线性混合模型共4种模型, 在群落和物种2个水平分析密度制约对不同生活史阶段个体存活率的影响及其相对重要性。结果表明, 群落水平上, 同种邻域效应对所有生活史阶段的存活率都有较为显著的影响, 幼苗的存活率受到同种成树较显著的负向影响以及同种幼苗邻体的显著正向影响。幼树和成树阶段的存活率均受到同种邻体的显著负向影响。同种负密度制约(CNDD)随着生活史阶段而减弱。异种邻域效应随生活史阶段和邻域半径的变化而变化, 但没有明确的趋势。物种水平上, 仅在成树阶段, 邻域效应在物种间存在较显著的差异, 在其他生活史阶段, 同种邻域效应和异种邻域效应在种间的差异均不显著。负密度制约现象存在于该温带森林的所有生活史阶段, 且CNDD随生活史阶段减弱, 异种负密度制约对不同生活史阶段个体存活率的影响受邻域尺度影响, 但没有体现明显的趋势。由于受到“异群保护效应”或适宜生境等的影响, 同种幼苗邻体对幼苗个体的存活率呈现正向影响。受物种生活史策略、生活型及物种多度等影响, 邻域效应存在种间差异。该研究结果显示, 在探究影响局域尺度森林群落物种共存的机制时, 需结合多物种和多生活史阶段进行综合分析。

关键词: 密度制约, 生活史阶段, 邻域分析, Janzen-Connell假说

Abstract:

Aims Our aim is to explore density dependence across various life stages trees in temperate forests and determine the varying importance of density dependence at different life stages. We seek to provide a theoretical foundation for species coexistence at a local scale in these forest systems.

Methods Utilizing tree census data and the dynamic monitoring data from 451 seedling quadrats in a 21.12 hm2 plot of coniferous and broadleaf mixed forest in Jiaohe, Jilin over three consecutive years (2016-2018), the effects of density dependence on different life stages were analyzed at community and species levels by four models: generalized linear mixed model, generalized linear mixed model incorporating the interaction between individual size and conspecific (heterospecific) neighbor variables, generalized linear mixed model incorporating conspecific neighbor variables and heterospecific neighbor variables as random effects, specialized generalized linear mixed model with sole incorporation of conspecific (heterospecific) neighbor variables as random effects.

Important findings At the community level, conspecific neighbors significantly affected the survival rate across all life stages. Conspecific adult tree neighbors exhibited a significant negative impact on seedling survival rate, while conspecific seedling neighbors had a positive effect on seedling survival rate. The survival of both saplings and adult tree stages was significantly and negatively affected by conspecific neighbors. The Conspecific Negative Density Dependence (CNDD) attenuated in response to life stages. Heterospecific neighbor effects varied in accordance with life stage and neighbor radius, without a well-defined trend. At the species level, the neighborhood effect differed significantly among species solely at the adult tree stage, and neither the conspecific neighborhood effect nor the heterospecific neighborhood effect differed significantly among species at other life stages. Negative density constraints existed in all life stages of this temperate forest, while CNDD decreased with life stage. The effect of heterospecific negative density constraints on the survival rate of individuals in different life stages was influenced by the scale of the neighborhood, without any apparent trend. As a result of the “herd immunity effect” or suitable habitat, the survival of individual seedlings was positively affected by conspecific seedling neighbors. Neighborhood effects varied among species depending on their life history strategies, life types and species richness. The results of this study suggest that the mechanisms affecting the coexistence of species in forest communities at the local scale require comprehensive analyses that incorporate multiple species and life stages.

Key words: density dependence, life stage, neighborhood analysis, Janzen-Connell hypothesis