Spatial patterns and ecological drivers of tropical moist forest transitions in the Kahuzi Biega National Park landscape eastern Democratic Republic of Congo

Kahuzi-Biega National Park (KBNP) is recognised as a Key Biodiversity Area for its large tracts of undisturbed tropical moist forest (UTMF) and exceptional wildlife. Since 1996, civil unrest and armed incursions have placed severe pressure on these forests, accelerating both degradation and outright loss. In this study, we examined how UTMF has changed across the KBNP landscape between 1990 and 2023, with the goal of identifying the main transition pathways and their underlying drivers. We used 30-m resolution Landsat land-cover maps from Vancutsem et al. (2021) together with field observations covering 15.7 ha to construct a 33-year transition matrix. Ten most common pathways were analysed in detail. For each, 600 pixels of interest were sampled and surrounded by three spatial windows (90 × 90 m, 270 × 270 m, 810 × 810 m) to calculate patch density, largest patch index, and total edge length. We also measured altitude and distances to roads, settlements, mines, and burned areas, and tested their influence using logistic regression. Results show that degradation accounted for 10.2% of transitions and direct deforestation for 5.8%. Stable UTMF occurred in homogeneous landscapes with high largest patch index and low edge length. Degradation was concentrated at low altitude s close to roads, while deforestation was more frequent at higher altitudes near burn scars. Zones of secondary-forest regrowth tended to lie in remote, inaccessible terrain. The mapped hotspots highlight priority areas where reinforcing conservation measures could help protect the park’s remaining intact forest.