By Abbas Nazil
Sub-Saharan Africa has lost 24 percent of its biodiversity since pre-industrial times, according to a new study that provides one of the most detailed assessments of ecological decline across the region.
The research, published in *Nature* on December 3, 2025, analysed biodiversity intactness using a new Africa-focused index (bii4africa) developed through the knowledge and insights of 200 African biodiversity experts.
The study estimates the region’s current Biodiversity Intactness Index at 76 percent, meaning indigenous plant and vertebrate populations have declined to 76 percent of their original abundance.
The findings highlight that biodiversity losses vary significantly across species groups, with disturbance-adapted herbaceous plants losing less than 20 percent of their intactness, while certain large mammals have experienced declines of up to 80 percent.
Rwanda and Nigeria emerged as the least biologically intact countries, with biodiversity levels below 55 percent, reflecting intense human pressure, habitat degradation, and rapid land-use changes.
Namibia and Botswana remain the most intact, maintaining biodiversity levels above 85 percent, largely due to extensive natural landscapes and lower population pressures.
The study reveals that more than 80 percent of remaining wild species in the region persist outside protected areas, thriving mainly in natural forests and rangelands where communities depend directly on biodiversity for livelihoods and survival.
Researchers warn that conserving biodiversity in these working landscapes is critical, as they support over 500 million people while sustaining essential ecosystem functions.
The main drivers of biodiversity loss differ by ecosystem: grasslands and fynbos are threatened primarily by agricultural expansion, forests face non-agricultural forms of degradation, and savannas experience a mix of both pressures.
Intensive croplands in the region, especially in grasslands, show significantly lower biodiversity intactness compared to smallholder croplands typical of savannas.
The study notes that cropland is expected to double and cereal demand to triple by 2050, raising concerns over further biodiversity decline as agricultural practices intensify in response to food security demands.
Central African countries retain some of the highest biodiversity intactness, attributed to the persistence of humid forests, while West Africa shows severe degradation driven by overharvesting and agricultural expansion.
Researchers maintain that this assessment offers policymakers context-specific and practical information needed to address biodiversity decline in one of the world’s most understudied regions.