Understanding the true state of biodiversity in sub-Saharan Africa has long been a challenge, especially for those responsible for shaping environmental policies. A major new study published in the prestigious Nature journal now offers much-needed clarity.
The research paper, “A place-based assessment of biodiversity intactness in sub-Saharan Africa”, provides one of the most detailed overviews to date of how plant and animal populations have changed across the region. Prof. Frances Siebert, a botanist in the School of Biological Sciences of the Faculty of Natural and Agricultural Sciences at the North-West University (NWU), says the study helps to fill a crucial knowledge gap that has long been an obstacle in effective planning.
“For many years, there has been a shortage of context-specific biodiversity information. This work directly addresses that,” she says. Prof. Siebert co-authored the paper with colleagues from several universities and led the forb (non-grass herbaceous plants) specialist group tasked with assessing vegetation-related biodiversity loss across the region.
“As a scientist and a proud sub-Saharan citizen with a strong passion for biodiversity, I feel extremely honoured to have contributed to this project, which had the vision to strengthen the voice of Africa for Africa when it comes to biodiversity conservation,” says Prof. Siebert.
Place-based expertise reveals significant biodiversity losses
The study draws on insights from two hundred African biodiversity experts, providing a rare, on-the-ground perspective of ecological change. The experts, who all hold credibility, legitimacy and saliency for mainstreaming into national decision-making and contribute to inclusivity and decoloniality in science, ranged from conservationists with a remarkable sense of change to scientists who have studied various taxa in Africa for several years.
The findings are concerning: on average, sub-Saharan Africa has lost 24% of its pre-colonial and pre-industrial faunal and floral population sizes. “Losses vary widely from under 20% for disturbance-adapted herbaceous plants to as high as 80% for certain large mammals,” says Prof. Siebert.
The research identifies Rwanda and Nigeria as the least intact, with biodiversity levels below 55%. In contrast, Namibia and Botswana remain the most intact, with levels above 85%. Importantly, many of the remaining organisms can be found outside protected areas, surviving mostly in unprotected rangelands and natural forests, which underpins the necessity to protect biodiversity while practising livestock farming.
Supporting policymakers with relevant insights
The research shows that the drivers of biodiversity loss differ across ecosystems.
“In grasslands and fynbos, biodiversity loss is linked to land being converted for farming. Forest regions face mostly non-agricultural forms of degradation, while savannas experience a combination of both pressures,” says Prof. Siebert.
She emphasises that the study offers policymakers information that is both contextually relevant and practical for an understudied region of global importance. “It integrates expert-derived, place-based knowledge into a multiscale assessment,” she explains. “Until this attempt to quantify ecosystem conditions in sub-Saharan Africa, assessments were based on top-down approaches built on global inventories that extrapolate across data-poor regions, such as Africa.”
Prof. Siebert says such approaches can have lasting consequences for conservation planning and restoration prioritisation in the global South. “For example, earlier attempts did not differentiate between planted pastures and untransformed rangelands, and large areas in Africa have therefore been inappropriately identified as targeted restoration areas through tree planning. This will threaten the remaining biodiversity in vast open rangelands in Africa and their livelihoods that depend on the ecosystem services they provide.”
She explains that, moreover, sub-Saharan Africa has the fastest-growing human population on Earth, which leads to rapid transformation that could compromise sustainable development into the future when context-appropriate biodiversity assessments continue to be ignored.
According to her, the same approach of the new study could be applied effectively elsewhere, even in regions with more extensive datasets. “It will certainly strengthen our understanding of biodiversity status in different areas and of the impact humans have on it,” she concludes.
“A place-based assessment of biodiversity intactness in sub-Saharan Africa” can be read in Nature at https://www.nature.com/articles/s41586-025-09781-7.
Prof. Frances Siebert from the School of Biological Sciences at the NWU. Prof. Siebert and postgraduate students from the NWU, and Prof. Sally Archibald from Wits, are also working on another and separate Africa-based research programme sponsored by the Oppenheimer Generations Conservation Trust. This project quantified biodiversity and soil organic carbon loss when natural grasslands were converted to croplands and left abandoned. “As African citizens, we should treasure our natural rangelands. Sustainable livestock farming in Africa is crucial, not only to optimise productivity, but also to protect biodiversity, as our data suggested in the paper,” Prof. Siebert says.
