The oasis expansion and eco-environment change over the last 50 years in Manas River Valley, Xinjiang

Abstract

The oasis expansion and economic development of the Manas River Valley is one of the most successful examples in Xinjiang. In this paper, the oasis spatial distribution pattern and dynamic change were examined using imageries of Landsat MSS, TM and ETM, land use and topographic maps in six different periods (such as 1949, 1962, 1976, 1989, 1999 and 2001) over the last 50 years in the valley. The oasis expansion process could be divided into two stages according to the annual rate of oasis area increase, the fast oasization stage (from 1949 to 1976) when the oasis area expanded from 156.385 km 2 in 1949 to 3,639.491 km 2 in 1976 because of rapidly increased population and quickly enlarged farmland area; and the urbanization stage (from 1976 to 2001) when the expansion ratio of farmland slowed down, and the urbanization process quickened, the total oasis area reached 5042.440 km 2 in 2001. With the continuous expansion of oasis and farmland, a large quantity of river water was drawn into irrigation ditch and plain lakes, so only a small quantity of river water could flow into lakes, as a result, the Manas Lake dried up, salization and basification problems happened in the low-lying oasis region. The natural swamp around the lake was shrunk greatly and biodiversity decreased significantly. The driving force analysis reveals that human activities, such as reclamation and population growth, played a major role in the oasis expansion and ecological deterioration in the Manas River Valley. So further efforts should be made to improve the efficiency of water resource utility and adjust layout of the regional agricultural and animal husbandry to keep the sustainable development of oasis economic belt of the northern slope of Tianshan Mts.

Analysis of land cover change and its driving forces in a desert oasis landscape of Xinjiang, northwest China

“…Previous studies on the land use/cover changes of oases in Xinjiang have mainly focused on farmland expansion, land use change, vegetation cover, soil properties, land desertification and their environmental impacts (Li et al, 2004a;Wang, 2004;Cheng et al, 2006;Tang et al, 2007;Wang et al, 2009;Luo et al, 2010;Liu et al, 2010), including the description of severe reductions of desert-oasis ecotones due to desertification and the loss of natural vegetation (Ding et al, 2006;Sun et al, 2007). These studies have generally described the processes and trends of land use/cover changes in desert oasis landscapes.…”

MODIS-Derived Spatiotemporal Changes of Major Lake Surface Areas in Arid Xinjiang, China, 2000–2014

“…This lake is about 55 km long and 15-20 km wide, with an area of about 550 km 2 and an average depth 6 m [41]. Our results show a decreasing trend of Manas Lake from 2000 to 2014.…”

“…A decreasing trend of precipitation and temperature was observed at the meteorological station near Manas Lake (Table 5). Manas River Valley is a representative area for oasis exploitation in Xinjiang as a primary agricultural production region and core region of economic development of the northern slope of the Tianshan [41]. The expansion of oasis in Manas River Valley was characterized by the spread of settlements and agricultural lands.…”

Expansion of agricultural oasis in the Heihe River Basin of China: Patterns, reasons and policy implications

“…In consideration of the high irrigation rate of an agricultural oasis, we defined the cultivated land in HRB as the agricultural oasis. The driving forces were selected in accordance with previous researches (Amuti and Luo, 2014;Cheng et al, 2006;Deng and Bai, 2014;King and Thomas, 2014;Xie et al, 2014;Zhao and Chang, 2014) and the personal knowledge of authors of this paper. The first independent variable we selected is the rural labor force (Table 1).…”

“…Therefore, the oasis ecosystem directly influences the environmental and social security in arid and semi-arid regions. The oasis change has been one of the key issues in the sustainable development in recent decades (Cheng et al, 2006).…”