Qi-Li Li

Assessing ecological changes along transport corridors is essential for protecting landscape integrity and ecosystem services, especially in ecologically fragile areas, yet integrated comparisons across geomorphic settings in this fragile alpine region remain limited. This study examined landscape patterns, carbon sequestration, and habitat quality in the basin–mountain transition and plateau–valley sections of a railway corridor extending from the western Sichuan Basin to the southern Qinghai–Tibet Plateau from 2017 to 2024. We found the following main findings: (1) The basin–mountain transition section showed declining patch density and landscape diversity, with reductions of approximately 43% and 12% within 5 km, compared with 38% and 8% within 10 km. In contrast, largest-patch dominance increased in the plateau–valley section at both scales. (2) Construction-period changes were more pronounced in the basin–mountain transition section, where the lowest landscape-division class increased from 52.71% to 60.01%, whereas spatial patterns remained relatively stable in the plateau–valley section. (3) Declining carbon sequestration and habitat quality occupied 14.25% and 12.31% of the basin–mountain transition section, compared with 4.42% and 3.91% of the plateau–valley section. Both services increased approximately linearly with distance in the former but peaked at approximately 7–9 km in the latter. (4) Habitat quality was positively associated with precipitation and negatively with temperature overall. The temporal trend became more positive with distance from the corridor, and temperature associations turned positive beyond approximately 8 km in the plateau–valley section. These findings support differentiated monitoring and management of transport corridors in alpine and ecologically fragile regions.