生物多样性 ›› 2016, Vol. 24 ›› Issue (3): 252-261.DOI: 10.17520/biods.2015282

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天山雪岭云杉森林群落的密度制约效应

王慧杰1, 常顺利1,*(), 张毓涛2, 谢锦1, 何平1, 宋成程1, 孙雪娇1   

  1. 1 新疆大学资源与环境科学学院绿洲生态教育部重点实验室, 乌鲁木齐 830046
    2 新疆林业科学院森林生态研究所, 乌鲁木齐 830063
  • 收稿日期:2015-10-21 接受日期:2016-01-11 出版日期:2016-03-20 发布日期:2016-04-05
  • 通讯作者: 常顺利
  • 基金资助:
    国家自然科学基金(U1503187)和新疆自治区科技支撑计划项目(201331125)

Density-dependent effects in Picea schrenkiana forests in Tianshan Mountains

Huijie Wang1, Shunli Chang1,*(), Yutao Zhang2, Jin Xie1, Ping He1, Chengcheng Song1, Xuejiao Sun1   

  1. 1 Key Laboratory of Oasis Ecology of Ministry of Education, College of Resource and Environment Sciences, Xinjiang University, Urumqi 830046
    2 Institute of Forest Ecology, Xinjiang Academy of Forestry, Urumqi 830063
  • Received:2015-10-21 Accepted:2016-01-11 Online:2016-03-20 Published:2016-04-05
  • Contact: Chang Shunli

摘要:

密度制约是维持自然森林群落物种共存的重要机制之一。雪岭云杉(Picea schrenkiana)是天山森林群落的单优种, 在我国温带森林中占有重要地位。本文基于对天山雪岭云杉8 ha森林动态监测样地的两次调查结果, 分析了该样地群落物种组成的动态变化, 运用点格局方法分析了雪岭云杉个体在不同龄级的空间分布格局及其关联性, 探讨了该群落的密度制约效应。结果表明: (1)该样地内, DBH ≥ 1 cm的木本植物在2009年有11,835株, 2014年为11,050株, 5年间的个体死亡率为8.82%, 补员率为2.19%, 个体株数净减少6.63%。(2)使用双关联函数g(r)分析了不同龄级雪岭云杉的空间分布格局, 发现幼龄树和中龄树在0-40 m尺度上主要呈现聚集分布, 但随着尺度增大聚集强度逐渐减小; 老龄树在0-2 m及4 m尺度上呈随机分布, 在其他尺度上呈聚集分布, 但聚集程度较小。(3)用“案例-对照”设计的方法, 排除生境异质性的影响后, 将幼龄树和中龄树作为案例, 老龄树作为对照, 对比幼龄树、中龄树与老龄树的分布格局, 发现雪岭云杉幼龄树和中龄树在0-40 m尺度上呈现额外的聚集, 随着径级的增大, 这种额外的聚集强度逐渐减小, 即表现出密度制约效应。(4)老龄树与中龄树、幼龄树的空间关联性相同, 在0-40 m尺度上均呈明显负关联。

关键词: 动态监测样地, 密度制约假说, 空间分布, 雪岭云杉, 天山

Abstract

The density-dependence hypothesis is one of the most important mechanisms proposed to explain species coexistence in natural forest communities. Picea schrenkiana is the single dominant species of the forest communities in Tianshan Mountains, which plays a very important role in temperate forests of China. We used reexamined data with a five-year interval on an 8-ha P. schrenkiana forest dynamics plot to illustrate the dynamics of species composition. Pointpattern analysis was conducted to reveal the spatial structure of P. schrenkiana individuals of different ages, and the effects of the density-dependence hypothesis on different ages of P. schrenkiana was discussed. The results were as follows: (1) Woody plants with DBH ≥ 1 cm were 11,835 trees in 2009 and 11,050 in 2014. The mortality rate was 8.82%, the recruitment rate was 2.19%, and the net decrease was 6.63%; (2) Young and medium trees of P. schrenkiana presented an aggregation distribution across a scale of 0-40 m, and the aggregation intensity decreased as the scale increased. Mature trees presented a random distribution on scales of 0 m ≤ r ≤ 2 m and r = 4 m, and an aggregation distribution on other scales with a low density. (3) Using a “case-control” design method and eliminating habitat heterogeneity, the distribution of young and medium trees were taken as examples of case. The distribution pattern of mature trees was used as a comparison and represented habitat heterogeneity, and was compared with that of young and medium trees. Young and medium trees of P. schrenkiana were observed to present more considerable gathering than was observed for mature trees on scales of 0-40 m, and density decreased while the diameter class increased. These results indicate that the density-dependence hypothesis has an influence on distribution patterns of different age classes. This study reveals that P. schrenkiana was affected by habitat heterogeneity and presented a significant aggregation effect. The spatial pattern of P. schrenkiana is revealed to be affected by the density-dependence hypothesis after eliminating the effects of habitat heterogeneity. The results of this paper support the Janzen-Connell hypothesis.

Key words: dynamics plot, density-dependence hypothesis, spatial distribution, Picea schrenkiana, Tianshan Mountains