JOURNAL OF NATURAL RESOURCES ›› 2014, Vol. 29 ›› Issue (3): 410-419.doi: 10.11849/zrzyxb.2014.03.005

• Resources Ecology • Previous Articles     Next Articles

The Ecological Risk Assessment of Arid Inland River Basin at the Landscape Scale:A Case Study on Shiyang River Basin

ZHANG Xue-bin1, SHI Pei-ji1, LUO Jun2, LIU Hai-long1, WEI Wei1   

  1. 1. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China;
    2. College of Resources and Environmental Science, Gansu Agricultural University, Lanzhou 730070, China
  • Received:2012-10-16 Revised:2013-05-17 Online:2014-03-20 Published:2014-03-20

Abstract:

It is significant to make a reasonable assessment of ecological risk to optimize the landscape pattern, establish the ecological risk alarm mechanisms, minimize the risk of ecological environment and maintain the ecological function in river basin. The study, based on the remote sensing data of 1987, 2000 and 2010, chooses the typical arid inland river basin as the subject, divides the study area into 20 km×20 km risk area and analyzes the temporal-spatial distribution pattern of ecological risk in Shiyang River Basin. Proceeding from the structure of landscape ecological system, the landscape disturbance degree index, the fragile index and the loss degree index are used to build the integrated ecological risk index (ERI) in the study with the help of spatial analysis of GIS. The results show that: 1) Great changes of landscape have taken place in the study area during 1987-2010, arable, woodland and grassland area have respectively reduced by 2.46×104 hm2, 4.77×104 hm2 and 12.73×104 hm2, while the residential land, water and unused land area have increased by 1.79×104 hm2, 2.58×104 hm2 and 15.59×104 hm2, which mean that the predominant of arable land, woodland and grassland decrease gradually, while the predominant of water, unused land and residential land increase gradually. 2) According to scope of ERI, 5 ecological risk grades are separated by ‘natural breaks’. If 0.12 ≤ERI ≤0.17, then the ecological risk grade is extremely low; if 0.17 <ERI ≤0.22, the ecological risk grade is low; if 0.22< ERI ≤ 0.27, the ecological risk grade is medium; and if 0.27 4 hm2; the low ecological risk areas spread to the upper and middle stream, and the area increases 29.30×104 hm2; the extremely high ecological risk areas expand to the downstream, and the area increases 58.69×104 hm2. 4) There are seven conversion modes of ecological risk, among which the overall performance is from low-grade ecological risk to high-grade ecological risk. The conversion area from low-grade to high-grade is 122.56×104 hm2, while conversion area from high-grade to low-grade is 6.12×104 hm2.

Key words: landscape ecological risk, Shiyang River Basin, ecology, spatial analysis

CLC Number: 

  • Q149