Analysis of Rocky Desertification Monitoring Using MODIS Data in Western Guangxi, China - Advances in Data, Methods, Models and Their Applications in Geoscience - page 299

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Analysis of Rocky Desertification
Monitoring Using MODIS Data
in Western Guangxi, China
Yuanzhi Zhang 1,* , Jinrong Hu 1 , Hongyan Xi 1 ,
Yuli Zhu 1 and DongMei Chen 2
1 The Yuen Yuen Research Center for Satellite Remote Sensing, Institute of Space and
Earth Information Science, The Chinese University of Hong Kong, Shatin,
2 Department of Geography, Queen's University, Kingston, Ontario,
1 Hong Kong
2 Canada
1. Introduction
Rocky desertification (RD) is the process of land degradation characterized by soil erosion
and bedrock exposure. It is one of the most serious land degradation problems in Karst
areas especially in western Guangxi of southwest China, which is usually regarded as an
obstacle to the local sustainable development. Recent investigations suggest that the RD is
mainly caused by direct human activities, but some researchers also take account the climate
change into a key factor of RD (e.g., Yao et al., 2001; Jing et al., 2003; Liao et al., 2004; Hu et
al., 2004; Wang et al., 2004; Xiong et al., 2008).
Most areas in the western part of Guangxi Province belong to the Karst region. Similar to the
other Karst areas in the southwest China, the geological environment is fragile and sensitive,
with a high density of population but a low degree economic development. These aspects
make the environment degraded quickly. RD is one of the most serious weaknesses of
sustainable development in western Guangxi of southwest China. The investigation of the
RD and its change monitoring are very significant and also necessarily meaningful.
In Guangxi, the area of Karst regions is about 89,500 km 2 , which takes up 37.8% of the total
area of Guangxi Province. Among them, the exposed surface of the Karst area is about
78,800 km 2 , at 88% of the total Karst area in Guangxi. In the past few decades, due to
deforestation, over cutting and grazing, the forest in the mountains was severely damaged,
which led to serious soil erosion. According to the recent survey, the RD land is more than
233×104 hm 2 , about 10% of the total area of Guangxi; the potential RD land area is more
than 186×10 4 hm 2 , about 8% of the total area. The RD land is mainly distributed in the
middle of Guangxi: Red River Basin, Liujiang Basin; and western Guangxi: Left, Right River
Basin; northeast of Guangxi: the two sides of middle and lower reaches of Li River. There
are 32 counties (cities, districts), and Karst areas take up more than 60% of the
administrative areas. The typical characteristics of RD areas are lack of soil, water, food and
fuel with a lower economic level. 28 counties are designated to be poor ones, and 23 of them