Biodiv Sci ›› 2016, Vol. 24 ›› Issue (4): 421-430.DOI: 10.17520/biods.2015300

Special Issue: 中国西南干旱河谷的植物多样性

• Original Papers • Previous Articles     Next Articles

Comparison of plant species diversity and composition in the dry valleys of Yalong River and Dadu River: evaluating the effects of climate, topography and space

Jie Han1, Zehao Shen1,*(), Songlin Shi2,3, Peihao Peng2   

  1. 1 Department of Ecology, College of Urban and Environmental Sciences, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871.
    2 College of Tourism and Urban-rural Planning, Chengdu University of Technology, Chengdu 610058.
    3 State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100875
  • Received:2015-11-01 Accepted:2016-02-02 Online:2016-04-20 Published:2016-05-11
  • Contact: Shen Zehao

Abstract:

The vegetation of dry valleys is a suit of unique azonal ecosystems embedded in the Hengduan Mountains region of Southwest China, with the difference of plant communities between the valleys and the causal factors still elusive. In this study, we investigated the dry valleys of the Yalong River and the Dadu River and compared plant diversity. Different factors were found to impact the vegetation types between the two rivers. Elevation and topography (slope and aspect) impacted vegetation types of the Yalong River and mean annual precipitation impacted the Dadu River. Plant richness in the valleys of the two rivers decreased with greater mean annual temperature. From a north to south aspect, plant richness of the dry valley communities decreased in the Yalong River, while increased in the Dadu River. Richness of shrubs in both the Yalong River and the Dadu River were greater at increased slopes. The β diversity of plant community in the dry valleys of the Yalong River and the Dadu River was affected more by environmental than geographical distance. The effect of geographical isolation on the two rivers was approximately 5 times greater than the effect of geographical distance. This research fills the knowledge gap about plant diversity of dry valleys vegetation in the Yalong River and the Dadu River, and reference information for vegetation conservation in the dry valleys of the two rivers. In addition, it provides a practical method for the quantitative assessment of geographical isolation effect on regional biodiversity difference.

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Key words: dry valley, plant diversity, vegetation types, geographical isolation