DDD Conference

Mr. Abubakari Munna

The Right Tree in the Right Place: Mapping and Predicting Global-Scale Suitable Areas for Marula Tree (Sclerocarya birrea) Subspecies Cultivation, Conservation, and Use in Restoring Global Drylands

Sokoine University of Agriculture, Tanzania



Marula, Sclerocarya birrea, is a tropical tree native to Africa that is of economic importance, its subspecies have been used to restore drylands and introduced outside Africa as a pilot towards commercial cultivation. However, there is a global paucity of information regarding where subspecies can survive beyond their native ranges and with changing climates. We aimed to map and predict global-scale suitable areas for Sclerocarya birrea and its subspecies under the current and future climates. We used MaxEnt and occurrence data from Africa, climatic and topographical variables and, climate data from Max Planck Institute and Hadley Climate Center’s global Earth Systems Models under shared socio-economic pathways (SSPs) greenhouse gas concentrations, SSP3-7.0, for 2050 and 2080. The results revealed that the predictive power of our models was excellent with areas under the curves of 0.90 to 0.98. Suitable area for Sclerocarya birrea and its subspecies is mainly defined by potential evapotranspiration, continentality, temperature and, precipitation seasonality. Currently, suitable areas for S. birrea and its subspecies exist in all continents except Europe and Antarctica, occupying 3,751,057 km2 to 24,632,452 km2 of earth’s terrestrial area in 54 to 107 countries predominantly in global biomes with climatic conditions ranging from desert tropical to temperate humid. However, under future climates, the currently suitable areas will retract by 64 to 100%, shift to high latitudes, and be limited to global biomes spanning from tropical desert-to-desert temperate and Mediterranean warm. This information is important in guiding cultivation, conservation, and using Sclerocarya birrea subspecies to restore global drylands.

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