Ecological integrity of forest landscapes in the Kisangani region (DRC) using spatial analysis of edge effect exposure and magnitude of edge influence

Abstract Assessing long-term forest fragmentation is essential for understanding the ecological integrity of tropical landscapes. This study investigates historical trends in forest loss, patch configuration, and edge-related disturbances across four forest landscapes near Kisangani, Democratic Republic of the Congo: Masako, Mbiye, Yoko, and Yangambi, using satellite imagery from 1986 to 2024. Landscape metrics, including Relative Forest Area Change and Largest Patch Index (LPI), were used to characterize both compositional and configurational changes. Interior-to-edge (I/E) ratios, interior and edge areas, and edge-affected percentages were computed across four buffer distances (50–200 m) to assess edge influence, while patch area was analyzed in relation to edge-induced Land Surface Temperature (LST) variation. Finds reveal accelerating fragmentation in the peri-urban landscapes of Masako and Mbiye, especially after 2016. Both landscapes lost over 80% of forest cover between 1986 and 2024, with sharp LPI declines, near-complete disappearance of interior forests, and I/E ratios approaching zero. By contrast, Yangambi retained over 90% of its initial cover and Yoko over 60%, with higher LPI and limited edge exposure, indicating more stable spatial patterns. Edge-related thermal effects showed a significant inverse relationship between patch size and LST in Yangambi and Yoko, suggesting larger patches mitigate edge warming. In Masako and Mbiye, low R² values reflected advanced fragmentation and diminished thermal buffering capacity. These results highlight major ecological risks, including biodiversity loss and ecosystem service decline. Landscape-specific strategies are recommended: restoration, reconnection of remnant patches, agroforestry integration, and community resource management. For relatively intact landscapes, legal reinforcement, spatial monitoring, and environmental education are proposed to prevent further degradation.