生物多样性 ›› 2015, Vol. 23 ›› Issue (2): 149-156.DOI: 10.17520/biods.2014137

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亚热带常绿阔叶林林窗物种丰富度的影响因素

刘何铭1,2, 杨庆松1,2, 方晓峰1,2, 马遵平1,2, 沈国春1,2, 张志国1,2, 王樟华3, 王希华1,2,*()   

  1. 1 浙江天童森林生态系统国家野外科学观测研究站, 浙江宁波 315114
    2 华东师范大学生态与环境科学学院, 上海 200241
    3 中国科学院上海辰山植物科学研究中心, 上海 201602
  • 收稿日期:2014-06-30 接受日期:2014-09-28 出版日期:2015-03-20 发布日期:2015-04-09
  • 通讯作者: 王希华
  • 基金资助:
    国家自然科学基金重大国际合作项目(31210103920)

Influences on gap species richness in a subtropical evergreen broad- leaved forest

Heming Liu1,2, Qingsong Yang1,2, Xiaofeng Fang1,2, Zunping Ma1,2, Guochun Shen1,2, Zhiguo Zhang1,2, Zhanghua Wang3, Xihua Wang1,2,*()   

  1. 1 Tiantong National Forest Ecosystem Observation and Research Station, Ningbo, Zhejiang 315114
    2 School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241
    3 Shanghai Chenshan Plant Science Research Center, Chinese Academy of Sciences, Shanghai 201602
  • Received:2014-06-30 Accepted:2014-09-28 Online:2015-03-20 Published:2015-04-09
  • Contact: Wang Xihua

摘要:

林窗是森林群落物种多样性维持中十分重要的结构, 但其本身物种多样性的维持机制尚不清楚, 可能与相邻群落的物种丰富度、林窗面积以及土壤和地形因子等有关。本文选取浙江天童20 ha森林动态监测样地内的84个冠林窗作为研究对象, 分析了林窗内部以及不同距离邻域内的物种组成, 选取包含大部分林窗内物种(≥75%), 并且对林窗内物种丰富度影响最大的邻域作为相关邻域(林窗周围成熟植株通过种子传播影响林窗物种丰富度, 把距离冠林窗边缘5 m范围内的区域作为种源效应邻域; 由于距离林窗较近, 物种组成与林窗形成时仍存活个体的物种组成相似, 故把距离冠林窗边缘4 m范围内的区域作为距离效应邻域), 然后计算种源效应邻域内成熟植株的物种丰富度、距离效应邻域内所有植株的物种丰富度、冠林窗的面积、地形因子(海拔、坡度、坡向、凸度)和土壤因子(pH值、全氮、全碳、全磷), 最后对11个潜在的影响因素进行随机组合, 构建广义线性回归模型, 筛选最优模型(AICc最小)进行分析。结果显示: 种源效应邻域内成熟植株的物种丰富度和冠林窗面积显著影响林窗内物种丰富度, 其他因素并未对冠林窗内物种丰富度产生显著影响。上述结果说明, 冠林窗面积的大小以及外部种源的丰富程度是决定冠林窗内物种丰富度的主要因素, 其他因素可能只产生间接影响。

关键词: 林窗大小, 物种多样性, 种源, 冠林窗面积, 天童, 森林群落, 动态样地

Abstract

Canopy gaps, created by the death or disturbance of a mature tree, influence forest community structure. The opening of the canopy creates opportunity for species recruitment influencing species diversity in forest communities. However, the mechanisms that lead to species recruitment and the resulting diversity are still unclear. Factors that may affect species richness of canopy gaps include the gap area, species richness of adjacent areas (SSAA and SCAA represent the adjacent area where is the seed source of canopy gap and the adjacent area where species composition is spatially correlated with survivors in the canopy gap, respectively), topography, and soil nutrients. To test which factors significantly affect species richness, 11 parameters (canopy gap area, species richness of mature individuals in SSAA, species richness of all individuals in SCAA, slope, aspect, convexity, mean elevation, pH value, total nitrogen, total carbon, total phosphorus of each gap) were calculated for 84 canopy gaps in 20 ha Tiantong Dynamics Plot. The effect of SSAA and SCAA were quantified by species richness of mature individuals and richness of all free standing trees (DBH ≥ 1 cm) within 5 m and 4 m away from the edge of the gap, respectively. The size of adjacent area was defined as the area containing most of species present in the gap (≥75%) and having most significant effect on gap species richness. A generalized linear regression model was constructed for each random combinations of any subsets of 11 gap parameters. Our best model with lowest AICc showed that: only species richness of mature individuals in SSAA and the canopy gap area had a significant effect on the gap species richness. This result suggests that gap size and species richness of the seed source can directly influence species richness of canopy gaps. Additional factors may have an indirect influence and should be explored further.

Key words: gap size, species diversity, seed source, canopy gap area, Tiantong, forest community, dynamics plot