Evaluating the Impacts of Human Activity and Climate on Vegetation Dynamics Using an Integrated Human Activity Index: A Case Study of China's Loess Plateau

ABSTRACT In recent decades, human activities have gradually influenced climate variability, consequently changing vegetation dynamics. We examined China's Loess Plateau (LP), a semi‐arid, erosion‐prone region undergoing large‐scale ecological restoration and rapid socioeconomic change, providing a natural setting to contrast climatic and anthropogenic influences. However, annual, temporally continuous quantification of multidimensional human activity—needed to disentangle its effects from climate—remains limited in the LP. We built and validated an annual Integrated Human Activity Index (IHAI) (2000–2020) and quantified EVI responses to precipitation, temperature, and IHAI using Theil‐Sen trend estimation, the Mann‐Kendall test, Hurst‐based tendency types, and partial and multiple correlation analyses. The IHAI experienced a significant increase in LP, whereas the regional mean EVI rose from 0.446 in 2000 to 0.544 in 2020, indicating a trend of 0.002 year −1 ( p = 0.002), consistent with greening. Climate signals exhibited geographical heterogeneity; future tendency classifications were mostly influenced by erratic precipitation and reversals in temperature trends, underscoring climatic non‐stationarity. The relationships between climate and vegetation were generally favorable. In contrast, those between IHAI and EVI showed regional divergence and often negative correlations, with distinct differences observed across degradation, stability, and restoration zones. These patterns support an LP‐wide, province‐aware “Target‐Match‐Maintain” strategy. It prioritizes targeted controls in high‐risk degradation zones, matches interventions to local hydroclimatic constraints and human‐vegetation coupling, and maintains recovery gains through sustained, performance‐based restoration and climate‐resilient management to reduce reversal risk.