Adaptive planning for cultivation and conservation of Cajanus cajan (L.) Huth in Togo in the context of bioclimatic change

Abstract Climate change threatens species and crops. Understanding its impact along a range of climates is essential for developing effective conservation strategies and strengthening ecological resilience. This study examines the impact of climate change on the distribution of Cajanus cajan (L.) Huth in Togo. It is a key crop in tropical agriculture. It provides an important source of dietary protein, improves soil fertility through nitrogen fixation, and supports the livelihoods of smallholder farmers. Environmental variables were extracted from the 88 points of occurrence distributed across the five regions and subjected to principal component analysis to identify ecological subgroups. We modeled the distribution of these subgroups using the Maximum Entropy algorithm in R. We employed the weighted average of three climate models (HadGEM3-GC31-LL, IPSL-CM6A-LR, and MIROC6) for the SSP2-4.5 and SSP5-8.5 scenarios up to the year 2050. The results demonstrate that the models well (AUC = 0.85–0.96; TSS = 0.45–0.73 and SEDI = 0.66–0.87). The current distribution of C. cajan is primarily driven by edaphic and topographic factors in the southern and central regions, while climate variables dominate in the northern region. Projections for 2050 indicate a substantial reduction in ecological niches, reaching up to 85% under the SSP5-8.5 scenario. This is accompanied by increased habitat fragmentation and low niche similarity between subgroups. Priority cultivation areas are concentrated in the Central and Plateau regions and partially overlap with existing protected areas. These results underscore the importance of protecting key habitats and developing agroecological practices adapted to future climatic conditions to ensure the resilience and sustainability of C. cajan in Togo.