生物多样性 ›› 2013, Vol. 21 ›› Issue (2): 141-152.DOI: 10.3724/SP.J.1003.2013.12183

• 研究报告 • 上一篇    下一篇

长江三峡库区物种多样性的垂直分布格局: 气候、几何限制、面积及地形异质性的影响

李巧燕, 王襄平*   

  1. 北京林业大学森林资源与生态系统过程北京市重点实验室, 北京林业大学林学院, 北京 100083
  • 收稿日期:2012-09-17 修回日期:2013-03-12 出版日期:2013-03-20 发布日期:2013-04-02
  • 通讯作者: 王襄平
  • 基金资助:

    国家“十二五”科技支撑计划课题;高等学校博士学科点专项科研基金资助课题

Elevational pattern of species richness in the Three Gorges region of the Yangtze River: effect of climate, geometric constraints, area and topographical heterogeneity

Qiaoyan Li, Xiangping Wang*   

  1. Key Laboratory for Forest Resources & Ecosystem Processes of Beijing, College of Forestry, Beijing Forestry University, Beijing 100083
  • Received:2012-09-17 Revised:2013-03-12 Online:2013-03-20 Published:2013-04-02
  • Contact: Xiangping Wang

摘要:

为了验证生物多样性地理格局的几个重要假说, 即种–面积关系、水分–能量动态假说、几何限制(中域效应)假说和生境异质性假说, 作者以长江三峡库区维管植物物种丰富度沿海拔梯度的分布格局为例, 采用多元回归和方差分解方法, 研究了面积、气候、几何限制、地形异质性对多样性垂直格局的独立影响和协同作用, 及其对各植物类群(不同分布宽度、不同分布区类型和不同生长型)影响的差异。结果表明, 三峡库区各种植物类群的物种丰富度随着海拔上升均呈先升后降的单峰格局。水分–能量动态假说对多样性格局有很强的解释能力, 其总的解释力(> 93%)明显高于其他所有解释机制。但对于很多植物类群而言, 水分和能量的解释力中有很大一部分属于几何限制、面积及地形异质性等因素的协同作用。几何限制对分布宽度大的物种的多样性格局解释力很强, 但对分布宽度小的物种作用很小; 面积自身对物种丰富度解释力较强, 但在考虑了其他环境因素的影响时, 仅对少数植物类群有解释力; 地形异质性自身对多样性的解释能力很弱, 但在多元回归模型中起着必要的作用。综合来看, 水分–能量动态是解释三峡库区植物多样性垂直格局的最重要的机制。几何限制的作用随着物种分布宽度减小而递减; 地形异质性虽然对多样性垂直格局的影响较弱, 但也是一种必要的补充解释机制; 由于面积与气候、几何限制等因素存在强烈的共线性, 面积对植物多样性垂直格局的相对作用大小还需要进一步的系统比较研究。

Abstract:

In this paper, we explore altitudinal richness of vascular plant species in the Three Gorges region of the Yangtze River and test several hypotheses concerning geographic diversity patterns. Multivariate regression and variation partitioning analyses were used to examine the relative effects of area, climate, geometric constraints and topographical heterogeneity on altitudinal richness patterns, and also the differences among ecological groups (including species with different range sizes, growth forms and biogeographic affinities). Our results show that, water–energy dynamics have the strongest total effect (>93%) in explaining richness patterns for various species groups. However, for many species groups the effects of water–energy dynamics were largely shared with geometric constraints, topographical heterogeneity or area. Geometric constraints had strong effects on species with large ranges, but negligible effects on small-ranged species. Area showed relative strong correlation with species richness, but was excluded from multivariate models for most species groups, when other potential mechanisms were considered simultaneously. On the contrary, topographic heterogeneity showed weak correlation with richness patterns but was included in most of the final multivariate models. We concluded that water–energy dynamics were most important in explaining altitudinal richness patterns within the study region, while geometric constraints were important for species with large ranges. Topographic heterogeneity showed a weak but essential role in shaping altitudinal richness gradients, while the role of area on richness patterns requires further investigation because of the collinear relationships between area, geometric constraints and climatic gradients.