Resources Science ›› 2018, Vol. 40 ›› Issue (9): 1866-1877.doi: 10.18402/resci.2018.09.16

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Impact of landscape fragmentation on watershed soil conservation service——a case study on Bailongjiang Watershed of Gansu

Jinxi ZHANG(), Dongqing LIU, Jie GONG(), Xuecheng MA, Erjia CAO   

  1. Key Laboratory of Western China’s Environmental Systems (Ministry of Education)/College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
  • Received:2017-10-31 Revised:2018-03-11 Online:2018-09-20 Published:2018-09-14

Abstract:

Bailongjiang watershed of Gansu, a vital water conservation area and environmental fragile area in the upper Yangtze River, is one of the four major landslides and debris flow disaster areas in China. Here, soil conservation service is particularly important. However, the high-frequency and high-intensity human activities have deepened the degree of landscape fragmenta tion and soil erosion in recent decades. Therefore, the research on the impact of landscape fragmentation on soil conservation service can clarify their spatial correlation and provide scientific basis for the watershed ecosystem sustainability. Taking Bailongjiang watershed of Gansu as an example, the spatio-temporal dynamic of landscape fragmentation and soil conservation service was quantitatively characterized from 1990 to 2014 via landscape pattern index, grid analysis, and InVEST model. Meanwhile, the relationship between the two issues was also discussed from the perspectives of mathematical and spatial statistics. The results showed that: (1) Initially, the degree of landscape fragmentation increased and then decreased in the Bailongjiang watershed in Gansu from 1990 to 2014. Soil conservation service documented a changing trend of descending firstly then ascending. (2) In 1990~2014, the spatial negative correlation between soil conservation service and landscape fragmentation developed from nothing to increase gradually. (3) By 2014, the degree of landscape fragmentation illustrated a significant negative impact on soil conservation service in the following areas: the northern part of Tanchang County, the middle and the southern part of Wudu District, the southern part of Wen County, and the boundary belts of Tanchang-Zhouqu-Wudu. It is essential to obtain a better soil conservation service through the decrease of the landscape fragmentation in the above areas.

Key words: landscape pattern, landscape fragmentation, soil conservation service, Bailongjiang Watershed of Gansu Province