Quantifying the influences of natural and human factors on the water footprint of afforestation in desert regions of northern China.

To mitigate desertification and alleviate soil erosion, a wide range of ecological restoration initiatives have been implemented in arid and semi-arid areas, the water consumption of ecological projects and driving mechanisms received increasing attention to balance economy development and ecology restoration at different scales. In this study, the water footprint (WF) was employed as an indicator of water consumption by afforestation, and trend analysis, texture classification and geographical detector methods were used to identify the afforestation area and assess the influences of natural and human factors on the afforestation WF in the desert regions of northern China. The results revealed four major findings. (1) The afforestation area increased by 73,764.31 km, from 2003 to 2017, accounting for 2.42% of the study area. (2) On average, the afforestation WF increased from east to west, ranging from 0 to 58.9 m/gC, indicating its high spatial heterogeneity. (3) Potential evapotranspiration was the dominant factor influencing the afforestation WF, explaining 20.4% of the variation in afforestation WF. (4) The explanatory power of natural and human factors was disparate at the different scales and the interactions between different factors had higher impact than that of single factors. These findings could provide valuable information to support more sustainable ecological restoration science and interventions in arid and semi-arid areas.