植物生态学报 ›› 2011, Vol. 35 ›› Issue (8): 834-843.DOI: 10.3724/SP.J.1258.2011.00834

所属专题: 青藏高原植物生态学:种群生态学

• 研究论文 • 上一篇    下一篇

雅鲁藏布江中游河岸带几种主要沙生植物种群点格局分析

李海东*(), 沈渭寿, 方颖, 燕守广, 张慧, 赵卫   

  1. 环境保护部南京环境科学研究所, 南京 210042
  • 收稿日期:2011-04-06 接受日期:2011-06-09 出版日期:2011-04-06 发布日期:2011-07-28
  • 通讯作者: 李海东
  • 作者简介:*E-mail: hdli2009@yahoo.com.cn

Point pattern analysis of several psammophyte populations in the riparian ecotone in the middle reaches of Yarlung Zangbo River of Tibet, China

LI Hai-Dong*(), SHEN Wei-Shou, FANG Ying, YAN Shou-Guang, ZHANG Hui, ZHAO Wei   

  1. Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing 210042, China
  • Received:2011-04-06 Accepted:2011-06-09 Online:2011-04-06 Published:2011-07-28
  • Contact: LI Hai-Dong

摘要:

以雅鲁藏布江中游河岸带几种主要沙生植物为研究对象, 采用相邻格子法分别在不同生境条件下的藏沙蒿(Artemisia wellbyi)、藏白蒿(Artemisia younghusbandii)和砂生槐(Sophora moorcroftiana)种群设立4个20 m × 30 m的样方, 运用点格局分析方法, 研究了这几种沙生植物的种群结构、空间分布、空间关联及其影响因素, 以期为西藏高寒河谷风沙化土地植被恢复提供依据。结果表明: 1)藏沙蒿种群结构呈增长型, 藏白蒿和砂生槐种群结构呈衰退型。藏沙蒿和藏白蒿种群在所有尺度上均呈集群分布, 砂生槐种群随着尺度增大表现为集群→随机→集群→随机分布。沙生植物种群分布格局主要是由较小的大小级决定的, 而较大的大小级是造成种群分布格局波动的主要因素。2)这几种沙生植物种间正关联往往存在于一定的尺度范围内, 种间关联时常出现不同关联方式交替出现和摆动的现象。半裸露砂砾地和半固定沙地藏沙蒿-砂生槐种间关联均表现为无关联→正关联→无关联→正关联, 半裸露砂砾地藏沙蒿-毛瓣棘豆( Oxytropis sericopetala)种间关联表现为正关联→无关联→正关联→无关联→负关联, 藏白蒿-砂生槐种间关联表现为正关联→无关联。3)这几种沙生植物种群均随植株形体增大, 聚集强度减弱, 大小级较小时表现为集群分布, 随着大小级增大, 表现为随机分布或随机与集群分布交错出现。不同大小级的空间正关联随着植株形体大小差异的增大而减弱, 甚至会转变为负关联, 各大小级在较小的空间尺度上易表现为正或无空间关联。

关键词: 雅鲁藏布江中游, 沙生植物种群, 河岸带, 空间关联, 空间分布

Abstract:

AimsArtemisia wellbyi, A. younghusbandii and Sophora moorcroftiana are the major psammophyte populations on the aeolian desertified land in the riparian ecotone of the middle reaches of the Yarlung Zangbo River. Our objectives were to determine how spatial scales are related to population patterns and how species spatially adapt to semi-arid conditions in the riparian ecotone, as well as to provide theoretical foundation for vegetation restoration on sand dunes in the study area.

Methods We selected four representative plant communities under different habitat conditions in the riparian ecotone, measured the position, height and crown diameter of each individual in a 20 m × 30 m plot and studied the population structure, spatial distribution and association of these psammophyte populations using point pattern analysis.

Important findings The population structure of A. wellbyi on semi-exposed sandy gravel land and semi-fixed sandy land is that of a growing population, while A. younghusbandii and S. moorcroftiana on fixed sandy land both have the structure of a declining population. Artemisia wellbyi and A. younghusbandii both have a clumped distribution at different scales, while the distribution pattern of S. moorcroftiana changed from clumped to random to clumped to random as the scale increased. Spatial distribution is mainly determined by the smaller size classes, while fluctuations or changes of population distribution are mainly determined by the larger size classes. There is a scale effect among the studied populations, and positive spatial association occurs mainly at certain scales. Spatial association is often affected by plant size and environmental heterogeneity. The spatial association of A. wellbyi and S. moorcroftiana on semi-exposed sandy gravel land or semi-fixed sandy land changes from independent to positive to independent to positive. The spatial association of A. wellbyi and Oxytropis sericopetala on semi-exposed sandy gravel land changes from positive to independent to positive to independent to negative, and that of A. younghusbandiiand S. moorcroftiana changes from positive to independent. The degree of aggregation weakens with increasing plant size. The smaller size class has a clumped distribution, and the larger has a random distribution or random and clumped. The positive spatial association between different size classes of the same species appears to weaken when the difference of plant size becomes greater and even changes into negative spatial association, while the spatial association of various size classes at a smaller scale often is positive or independent.

Key words: middle reaches of Yarlung Zangbo River, psammophyte populations, riparian ecotone, spatial association, spatial distribution