Geographic Variation in Landscape Structure and Annual Climate Associations Across Cumulative Highway Buffer Scales

Landscape patterns along highways vary with the spatial extent examined, and similar responses may conceal differences in land cover and patch structure. We analyzed 14 nested cumulative buffer widths (0.05–10 km) across three sections of China’s Jinggang’ao Expressway from 2000 to 2020. Generalized additive models, block bootstrap resampling, annular land-cover comparisons, and temporal regressions were used to examine landscape structure and annual climate associations. Landscape Shape Index (LSI), Shannon’s Diversity Index (SHDI), and Largest Patch Index (LPI) showed nonlinear, section-specific patterns. Initial LSI minima occurred at 0.236, 0.288, and 0.343 km, respectively, and were consistently detected under temporal resampling, although their locations depended on model specification. Despite similar LSI patterns, land-cover composition differed among sections. From 250 to 500 m, cropland proportion (PLAND) decreased by 0.94–4.36 percentage points, while the share of cropland occupied by its largest patch increased by 5.14–11.69 percentage points. Climate associations were sensitive to temporal modeling; none of 36 coefficient tests passed false discovery rate correction under autoregressive models. Combining cumulative profiles, annular composition, and class-specific patch measures reveals structural differences that aggregate landscape metrics alone may obscure.