Spatiotemporal Evolution of the Ecological Network in Heilongjiang Province, China: A Structure-Oriented Approach Based on MCR and Backbone Corridor Identification

Ecological networks provide an important spatial framework for maintaining regional ecological security in fragmented landscapes. However, structural comparison of ecological network evolution at the provincial scale remains relatively limited, especially in cold-region contexts. Taking Heilongjiang Province in Northeast China as the study area, this study applies a structure-oriented workflow integrating ecological sensitivity assessment, the Minimum Cumulative Resistance (MCR) model, and edge-betweenness-based backbone corridor extraction to examine ecological network change in 2000, 2010, and 2020. The results show that 16, 18, and 17 ecological source areas were identified in 2000, 2010, and 2020, respectively, with a relatively stable spatial distribution concentrated in forest- and wetland-dominated regions. The total length of potential ecological corridors decreased from 12,634 km in 2000 to 11,985 km in 2020. Quantitative topological indicators further indicate that the 2010 ecological network was the most compact and densely connected of the three periods, whereas the 2020 network remained connected but exhibited lower structural compactness. Backbone ecological corridors retained only a limited proportion of the full corridor network while preserving overall connectivity, indicating that a relatively small subset of structurally important corridors supported the main network framework. Spatially, structural weakening was more evident in the Harbin–Daqing region, whereas the northwestern and southeastern parts of the province maintained relatively stable ecological foundations. These patterns were broadly consistent with land-use dynamics, particularly grassland decline and built-up land expansion. Overall, this study provides an applied structure-oriented workflow for examining ecological network evolution at the provincial scale and offers a spatial basis for ecological conservation and territorial planning in cold-region provinces.