Advances in Earth Science ›› 2006, Vol. 21 ›› Issue (4): 409-416. doi: 10.11867/j.issn.1001-8166.2006.04.0409

• Articles • Previous Articles     Next Articles

A Study of the Ecological Functions of Step-pool System in Southwest Mountain Streams

Wang ZhaoYin 1,2,Cheng Dongsheng 2,He Yiping 1,Wang  Hongzhu 3   

  1. 1.State key Laboratory of Hydro-Science and Engineering, Tsinghua University, Beijing 100084,China;2. International Research Training Center on Erosion and Sedimentation, Beijing 100044,China;3. Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072,China
  • Received:2005-09-05 Revised:2006-02-17 Online:2006-04-15 Published:2006-04-15

Wang ZhaoYin,Cheng Dongsheng,He Yiping,Wang Hongzhu. A Study of the Ecological Functions of Step-pool System in Southwest Mountain Streams[J]. Advances in Earth Science, 2006, 21(4): 409-416.

The development of step-pool system plays an important role in stream ecology. Step-pool system maximizes the flow resistance and protects the bed sediment from erosion. Thus the riverbed and bank slope are stabilized. Boulders, cobbles and gravel tightly interlock and form the steps having an inherent stability which only extreme floods are likely to disturb. Silt and clay deposit in the pools behind the steps. These steps and pools provide high diversity of habitats for stream bio-community. Field investigations are performed to the Xiaojiang River, Jinsha River and Jiuzhai Creek. Step-pool systems develop well in the Jiuzhai Creek and Shengou Ravine, which is a tributary of the Xiaojiang River. The density of benthic macro-invertebrate is 552/m2 in the Jiuzhai Creek and 398/m2 in the Shengou Ravine and the density of bio-mass of benthic macro-invertebrate is 4.75g/m2 in the Jiuzhai Creek and 5.96 g/m2 in the Shengou Ravine. As a comparison, the density of benthic macro-invertebrate is only 0.75/m2 in the Jiangjia Ravine and 0 in the Xiaobaini Ravine, which are also the tributary of the Xiaojiang River, but no step-pool develops in the ravines. The density of bio-mass of benthic macro-invertebrate is only 0.006 g/m2 in the Jiangjia Ravine and 0 g/m2 in the Xiaobaini Ravine. This paper proposes the concept of habitat diversity and a calculation formula considering the spacious distribution of various substrates, velocity and water depth. The study reveals that the biodiversity of benthic macro-invertebrates increases with the habitat diversity in a logarithmic law. Artificial step-pool system can be used for training of mountain streams, which may stabilize the streambed and bank slope, restore healthy river ecology and high biodiversity, and better aesthetic landscape as well.

No related articles found!
Viewed
Full text


Abstract