Abstract: Qinling Mountain is an important dividing line for North and South China, and also an important functional area of water conservation. Clarifying the temporal and spatial variation of its water conservation function is of great practical significance to realizing the rational utilization of regional natural resources and sustainable development in Qinling Mountain region. The water yield module of InVEST model was used to analyze the temporal and spatial variation of water yield and water conservation function in Qinling Mountain from 2000 to 2015. The quantitative analysis of the influencing factors of water conservation function was further conducted using stepwise regression analysis method. The results showed that the mean annual amount of water yield and water conservation in Qinling Mountain was 156.96×10⁸ and 61.51×10⁸ m³, respectively. The water conservation capacity of each city followed an order of Shangluo > Ankang > Hanzhong > Xi’an > Baoji > Weinan. The temporal and spatial variation of water conservation function significantly varied from 2000 to 2015, being higher in south and lower in north Qinling Mountain. The water conservation amount increased by 0.26 mm per year from 2000 to 2015. The spatial distribution of water yield and water conservation was basically the same as that of the annual precipitation, while it was negatively correlated with actual evapotranspiration. Land use was mainly stable from 2000 to 2015. The change of water conservation capacity caused by land use change varied from -65.2 mm to 14.4 mm per year. The water conservation capacity increased in forest land and decreased in grassland. Water conservation function had a strong correlation with aridity index, precipitation, and soil saturated hydraulic conductivity on the sub-basin scale. Aridity index, precipitation, and actual evapotranspiration were the main factors influencing water yield function.

Key words: water conservation function, InVEST Model, temporal and spatial variation, regression analysis, Qinling Mountain.