Quantitative assessment of driving factors behind the ecological effects of the Beijing–Tianjin sandstorm source region, China during past 20 years

The Beijing–Tianjin sandstorm source region (BTSSR) is an important ecological barrier in North China, which can prevent land desertification from spreading. However, the challenge of separating the impacts of climate change from those of human activities on ecological restoration remains a critical concern. This study addresses this issue by employing residual trend analysis to investigate long-term trends in net ecosystem productivity (NEP), water conservation (WC), soil erosion (SE), and habitat quality (HQ) in the BTSSR. The results showed that the ecological recovery of the study area was significantly improved. Notably, there is a significant increase in NEP, with affected areas constituting 68.88 % of the total, alongside a 56.11 % expansion in WC. Conversely, HQ showed a modest increase in 25.59 %, while SE experienced a significant decline in half of the study area. The strong positive correlation noted between NEP and summer precipitation, leading to the selection of NEP as a key index for assessing ecological restoration drivers. The research identifies engineering measures as the primary force propelling restoration efforts, contributing 38.18 %, followed by precipitation at 26.80 %. Predominantly, these impactful areas are situated in the southern region, where beneficial water and thermal conditions foster higher vegetation coverage. The methodology employed here enhances the precision of evaluating ecological engineering across various regions and climatic contexts, offering vital insights for national ecological governance and restoration initiatives.