Using paleoclimatic range reconstructions to analyse historical space shifts of Striped and Brown Hyenas

Niche theory suggests that two species with similar ecological roles can coexist only if they exhibit sufficient differentiation in resource use; otherwise, competitive exclusion may occur. The striped and brown hyena share similar niches, particularly in terms of diet and habitat preferences. Today, the brown hyena’s range is restricted to Southern Africa, while the striped hyena occupies a larger area from Kenya to India. Yet, fossil evidence suggests that these species could have occupied wider, potentially overlapping ranges historically. Brown hyena fossils have been found in Kenya and Ethiopia, while striped hyena fossils appear as far south as South Africa. To investigate the potential historical range shifts of both species during the last 120,000 years, we developed maximum entropy species distribution models (package megaSDM). We used occurrence data collated by the IUCN SSC Hyena Specialist group and HadCM3/ HadAM3H simulated climatic, bioclimatic and vegetation variables as  predictors. Our results indicate that during the Last Glacial Maximum (~21,000BP), a potential corridor with high habitat suitability existed between their current ranges, suggesting that the striped hyena could have extended its range into southern Africa, supporting previous fossil findings. We found that habitat suitability for both species has declined over time, likely driven by changes in precipitation, temperature, and biome type. Both species show a preference for regions with relatively low annual precipitation (with 700 mm as a maximum threshold), moderate temperatures (12–18°C), and arid landscapes. These results imply that fluctuating Pleistocene climates, particularly cycles of wetter and drier conditions in East Africa, likely caused shifts in suitable habitats, contributing to the contraction of both species' ranges. Understanding these historical dynamics provides insights into the ecological and climatic factors that have shaped the current distributions of striped and brown hyenas, with implications for conservation and management in the context of future climate change.