生物多样性 ›› 2009, Vol. 17 ›› Issue (6): 594-604.DOI: 10.3724/SP.J.1003.2009.09183

所属专题: 群落中的物种多样性:格局与机制

• 论文 • 上一篇    下一篇

植物群落物种共存机制: 负密度制约假说

祝燕, 米湘成, 马克平*()   

  1. 中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
  • 收稿日期:2009-07-06 接受日期:2009-11-17 出版日期:2009-11-20 发布日期:2009-11-20
  • 通讯作者: 马克平
  • 作者简介:*E-mail: kpma@ibcas.ac.cn
  • 基金资助:
    中国科学院知识创新工程重要方向项目(KZCX2-YW-430)

A mechanism of plant species coexistence: the negative density-dependent hypothesis

Yan Zhu, Xiangcheng Mi, Keping Ma*()   

  1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093
  • Received:2009-07-06 Accepted:2009-11-17 Online:2009-11-20 Published:2009-11-20
  • Contact: Keping Ma

摘要:

负密度制约假说主要描述由于资源竞争、有害生物侵害(比如病原微生物、食草动物捕食)等, 同种个体之间发生的相互损害行为; 它主要强调同种个体之间的相互作用, 解释自然群落物种共存的机理; 负密度制约机制主要在小尺度上降低群落内同种个体生长率, 同时提高个体死亡率, 从而为其他物种的生存提供空间和资源, 促进物种共存。目前负密度制约假说的检验研究主要侧重密度制约、距离制约、群落补偿效应等三个方面。最近, 研究者又探讨了近缘物种之间由于对相似资源的竞争所产生的负效应, 扩展了负密度制约假说, 进而提出异群保护假说和谱系多样性制约假说。负密度制约假说引起生态学家长久的探讨和关注, 世界范围内大尺度森林动态样地的建立, 又为探索不同尺度上密度制约效应的研究提供了条件。然而目前的研究仍然存在不足, 比如负密度制约假说的检验受到其他因素的干扰、区域研究不平衡等。因此, 生态学家们仍然怀疑负密度制约效应调节群落物种共存的重要性, 但是目前的研究还没有发现否定负密度制约假说的充分证据。

关键词: 密度制约, 同种个体, 距离制约, 群落补偿效应, 谱系多样性制约

Abstract

The negative density-dependent hypothesis focuses mainly on conspecific interactions to explain the coexistence of diverse species in natural communities. The hypothesis describes the impairment of performance among conspecific individuals due to resource competition, predation of pests (e.g., pathogen, herbivore) and so on. Impairment of conspecific individuals decreases growth and increases mortality, thereby freeing space for other species, and thus promotes coexistence of diverse species. There are three main kinds of density dependent effects including distance-dependence of mortality and abundance of offspring near parents (Janzen-Connell hypothesis), density dependent thinning (random-mortality hypothesis), and community compensatory trends (CCT). Research has shown that density dependence among phylogenetically closely-related species results partially from competition for similar resources. This fact led to the proposal of species herd protection and phylodiversity dependence models. Density dependence has long history of study and the recent establishment of a global network of large-scale forest dynamic plots facilitates the detection of density dependence in natural communities. However, there are many challenges when testing for density dependence. For example, some previous studies can not disentangle density dependence from other confounding effects, and most studies focus exclusively on the tropical zone, seldom considering other zones. Therefore, though strong evidence to contrary does not exist, debate continues on the importance of density dependence in maintaining diverse-species coexistence.

Key words: density dependence, conspecific individuals, distance dependence, community compensatory trend (CCT), phylodiversity dependence