Monitoring and analysis of grassland desertification dynamics using Landsat images in Ningxia, China
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- 作者：Jinya Li ; Xiuchun Yang ; Yunxiang Jin ; Zhi Yang ; Wenguang Huang ; Lina Zhao ; Tian Gao ; Haida Yu ; Hailong Ma ; Zhihao Qin ; Bin Xu
- 关键词：Grassland desertification ; Spectral mixture analysis ; Spatiotemporal analysis ; Grazing ban ; Ningxia
- 刊名：Remote Sensing of Environment
- 出版年：2013
- 出版时间：November, 2013
- 年：2013
- 卷：138
- 期：Complete
- 页码：19-26
- 全文大小：1352 K
文摘
State and local governments in China have implemented a series of grassland protection policies to address the problem of grassland degradation. In 2003, Ningxia was the first province to implement a province-wide grazing ban. The effect of this ban is contentious at all levels of government and has become a topic of public concern. Grassland desertification is the most direct indicator of the effect of the grazing ban. We selected 14 counties and cities in north-central Ningxia as the study area. A desertification classification and grading system for Ningxia's grassland was then designed based on fieldwork and expert review. Using the Spectral Mixture Analysis (SMA) and decision-tree methods, we interpreted Landsat TM/ETM + images of the study area during four years: 1993, 2000, 2006 and 2011. The following results were obtained: from 1993 to 2011, the area of desertified grassland in north-central Ningxia decreased gradually from 8702 km2 in 1993 to 7485 km2 in 2011, a decrease of 13.98 % ; the degree of desertification gradually decreased from 3573 km2 of severely desertified grassland in 1993 to 1450 km2 in 2011, a decrease of 59.41 % ; desertified grassland vegetation was restored rapidly during 2000-2006 and 2006-2011, reducing the total area of desertified grassland annually by 1.87 and 0.61 % , respectively; finally, the area of severely desertified grassland decreased annually by 5.78 and 6.28 % during 2000-2006 and 2006-2011, respectively. These results show that the region-wide grazing ban, together with other ecological engineering measures, has helped reverse desertification and promote the restoration of grassland vegetation.