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NDVI spatial distribution and its correlation with land-use in Dan River Watershed of Shaanxi Province |
Zhang Jun 1, 2, Jia Chunrong 2, Li Peng1, Tang Hui1 |
1.College of Water Resources and Hydraulic Power, Xi‘’an University of Technology, 710048, Xi‘’an, China;
2.College of Land and Resources, China West Normal University, 637009, Nanchong, Sichuan, China |
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Abstract [Background] Vegetation coverage is the main body of terrestrial ecosystem. Detecting the spatial distribution pattern of vegetation and its correlation with land-use will benefit the regional ecological environment protection and soil erosion control. [Methods] In this study, taking the Dan River Watershed, the water source of the middle route of the South to North Water Diversion Project, as the research area, MODIS 250-m NDVI data and GIS technology were used to obtain spatial distribution features of the different NDVI degree in the case of elevation, slope-degree and slope-direction via overlap of distribution maps of NDVI and topographic factors maps extracted from digital elevation model. Finally, the correlation between NDVI and land-use types was analyzed. [Results] The results showed that: 1) The average NDVI value was 0.85, which indicated that the ecological environment was fine in Dan River Watershed. The high vegetation coverage distributed in marginal areas of watershed, and relatively concentrated in northeast and southeast; while the middle vegetation coverage distributed in low mountain, and relatively concentrated in northwest and south. Low vegetation coverage distributed in the Dan River valley as point and linear way, especially in city area. 2) At the different elevation and slope- degree, the distribution of area percent of high and middle vegetation coverage was assumed as single peak. The vegetation coverage area percent was proximal zero in the flat. The vegetation coverage area in the case of different slope-directions was not different dramatically. 3) Except different slope-direction, at different elevation and slope-degree, the high and middle vegetation coverages were significantly correlated with farmland, forestland and grassland. Moreover, low vegetation coverage was significantly in correlation with construction land and waters in the different topographic factors. [Conclusions] Some conclusions have been obtained that the degree of vegetation coverage showed obvious revese distribution characteristics with human activities range in Dan River Watershed, which indicated that human activities had a great impact on vegetation distribution Optimization of land use structure and appropriate increase of area were beneficial to improve the soil and water conservation function of Dan River Watershed.
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Received: 29 June 2015
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