Quantification of the impacts of climate change and human agricultural activities on oasis water requirements in an arid region: a case study of the Heihe River basin, China

Ecological deterioration in arid regions caused by agricultural development has become a global issue. Understanding water requirements of the oasis ecosystems and the influences of human agricultural activities and climate change is important for the sustainable development of oasis ecosystems and water resource management in arid regions. In this study, water requirements of the main oasis in Heihe River basin during 1986-2013 were analyzed and the amount showed a sharp increase from 10.8 x 108 m(3) in 1986 to 19.0 x 108 m(3) in 2013. Both human agricultural activities and climate change could lead to the increase in water requirement. To quantify the contributions of agricultural activities and climate change to the increase in water requirements, partial derivative and slope method were used. Results showed that climate change and human agricultural activities, such as oasis expansion and changes in land cropping structure, has contributed to the increase in water requirement at rates of 6.9, 58.1, and 25.3 %, respectively. Overall, human agricultural activities were the dominant forces driving the increase in water requirement. In addition, the contribution of oasis expanding to the increased water requirement was significantly greater than that of other concerned variables. This reveals that controlling the oasis scale is extremely important and effective for balancing water for agriculture and ecosystems and to achieving a sustainable oasis development in arid regions.