Measuring sustainable development with the ecological footprint method——take Zhangye prefecture as an example Effect of farmers‘ perception on ecological compensation-A case study of Zhangye Prefecture in the Heihe River Basin Comparison environmental impact of the peasant household in han, zang and hui nationality region:case of zhangye,Gannan and Linxia in Gansu Province Analysis on structure and function of agro ecolomic system in oasis—taking Zhangye oasis as an example Spatial disparities and the reasons about the impact of the peasant household consumption on environment: based on the survey data of Zhangye city in 2010 COMMUNITY OF PHYTOPLANKTON IN ZHANGYE MAM-MADE FISHPONDS Contingent Valuation of the Economic Benefits of Restoring Ecosystem Services of Zhangye Prefecture of Heihe River Basin