Vegetation, lakes, and sandy areas in arid and semi-arid regions of Northern China: patterns, evolution, and driving forces

Landscape changes in northern China’s arid and semi-arid regions significantly affect ecological security and sustainable development. Understanding vegetation, lakes, and sandy area interactions is essential for landscape management. Using remote sensing data spanning 1980–2024 across 5.6 million km2, we integrated object-based classification, landscape metrics, Grey Relational Analysis (GRA), and Geodetector to quantify landscape dynamics and driving forces. Four key findings emerged. (1) Landscape evolution comprised three human-dominated phases: agricultural expansion (1980–2024) increased cropland by 7.59% (1980 baseline) while vegetation cover decreased by 2.66%; urbanization (2010–2024) expanded built-up land by 57.65%; a spatial pattern of western desertification and eastern urbanization emerged. (2) Fragmentation increased: patch density (PD) rose 18.70%, Shannon’s diversity index (SHDI) declined 9.2%; lakes experienced severe connectivity loss, with PD nearly doubling (+94%). (3) High vegetation cover stabilized sandy areas (r = 0.57, GRA = 0.74) and lakes (r = 0.58, GRA = 0.50); low cover correlated with degradation (r = −0.88 with sandy areas). Over the study period, 42% of small lakes (<1 km2) disappeared, and high-cover vegetation declined 34.70%. (4) Human activities – population (q = 0.54) and GDP (q = 0.49) – were the dominant driving forces, with precipitation secondary (q = 0.32). These findings reveal a cascade of agricultural expansion, urbanization, and subsequent ecological constraints under intensifying human-environment interactions, providing a scientific basis for ecological management. The methodology is transferable, and quantified thresholds offer targets for global desertification control.