Climate change-informed habitat suitability and conservation priorities for Cinchona species in eastern Democratic Republic of the Congo

Background and aims – Cinchona species, the botanical source of quinine, remain essential for treating severe malaria and support rural livelihoods in eastern Democratic Republic of the Congo. Yet, increasing climate stress and land degradation threaten its future habitat suitability. This study assessed current and mid-century habitat suitability for Cinchona in North and South Kivu provinces and prioritised areas for conservation and replanting. Material and methods – Potential distributions were modelled with MaxEnt using 125 validated occurrences and ten environmental predictors (five bioclimatic, three topographic, two edaphic). To limit multicollinearity, we pre-selected variables with |r| < 0.7 and VIF < 10. Future projections used 2050s CMIP6 climates under SSP2-4.5 and SSP5-8.5. Key results – Model performance was high. Thermal variability together with elevation most strongly explained suitability, indicating a preference for moderate thermal regimes at 1,400–2,300 m. Under current climate, high suitability covers 4.13% of the study area, moderate 6.49%, low 27.67%, and 61.71% is unsuitable. By the 2050s, high suitability contracts to 1.27% (SSP2-4.5) and 1.07% (SSP5-8.5), while unsuitable area expands to 81.72% and 83.90%, respectively. High-suitability zones cluster along the eastern escarpment, notably Lubero, Oïcha, Kabare, Walungu, and Butembo, whereas lowland territories such as Shabunda and Fizi become largely unsuitable. Conclusion – Our results delineate micro-refugia for in situ protection, guide climate-resilient replanting toward highlands, and indicate where ex situ measures and assisted restoration will be needed under future climate conditions.