Widespread Improvement in Comprehensive Ecosystem Service and Its Latitude-Dependent Upward Trend Along the Beijing–Hangzhou Grand Canal, China

The Beijing–Hangzhou Grand Canal (BHGC) is a globally recognized linear cultural heritage corridor; however, the fine-scale spatiotemporal dynamics of its comprehensive ecosystem services (ESs) remain poorly understood. Using 30 m high-resolution remote sensing-derived products, this study investigated the spatiotemporal trends and latitudinal patterns of net primary productivity (NPP), soil conservation (SC), water yield (WY), and the improved comprehensive ecosystem services index (CESI) along the BHGC corridor from 2000 to 2020. The improved CESI was constructed via a multiplicative method with cube-root transformation to capture the barrel effect and avoid the compensatory bias inherent in traditional additive approaches. Our results revealed that 91.7% of the pixels exhibited a widespread increasing tendency in CESI, accompanied by a pronounced latitudinal upward gradient from north to south. All three individual ESs improved overall during the study period, with WY increasing most extensively (94.7%), followed by SC (76.9%) and NPP (68.3%), respectively. High-CESI zones were concentrated in the Shandong, Jiangsu, and Zhejiang sections, while low-value patches were scattered across the northern Beijing–Tianjin–Hebei sections. Overall, this study provides a robust, fine-scale scientific basis for targeted ecological management and sustainable planning of the Grand Canal Cultural Belt.