Biodiversity in sub-Saharan Africa has decreased by 24 percent compared to pre-industrial times, according to a study published in Nature on Wednesday, 3 December.
On average, populations of plants and animals in the region have declined by nearly a quarter. Some species, particularly large mammals, have declined much more severely.
The estimate was compiled with the help of 200 local experts. The experts included researchers, field ecologists, park rangers, guides, and museum curators working in the region’s changing landscapes.
This extensive compilation effort took more than five years.
“Global biodiversity assessments are based on sparse local measurements. As a result, they generalize from areas where more data is available. For this reason, they do not represent African conditions particularly well,” says the study’s lead author, research fellow Haley Clements from the Department of Geosciences and Geography at the University of Helsinki.
The study also revealed large variations across ecosystems, countries, and species groups. Biodiversity among the most disturbance-tolerant plants has declined by only about 10 percent. In contrast, mammals such as elephants, lions, and certain antelope species have lost more than 75 percent of their historical abundance.
The main causes of the collapse are habitat loss caused by croplands, as well as hunting and livestock grazing at unsustainable levels.
Regional biodiversity has been best preserved in Central Africa, where continuous tracts of humid forest offer protection.
The greatest losses have occurred in West Africa. Of individual countries, Rwanda and Nigeria have lost the most biodiversity—and they also have the highest proportion of cropland.
One of the study’s key findings is that more than 80 percent of remaining wild plant and animal populations live outside protected areas—in forests and rangelands where people live alongside nature.
Cropland in sub-Saharan Africa is expected to double and cereal demand to triple by 2050. According to the authors, biodiversity-positive farming practices will be crucial for reconciling food security with ecosystem health.
“This fundamentally changes how and where we think biodiversity should be protected in Africa,” Clements says.
“Protected areas remain vital, especially for large mammals, but on their own they are not enough to stop the decline in biodiversity.
What is essential is the sustainable management of nature outside protected areas—through approaches that make it possible both to preserve biodiversity and to support local livelihoods.”
These findings are critical for informing the Kunming-Montreal Global Biodiversity Framework (GBF) and the UN Sustainable Development Goals (SDGs), as well as other national to local policies.
''The GBF’s targets, such as conserving 30% of land and ensuring sustainable use of biodiversity, cannot be met by focusing solely on protected areas. This study underscores the need for approaches that integrate conservation policies within broader policies for sustainable development.'' says Prof. Enrico Di Minin at the University of Helsinki, a co-author in the article.
''It also supports progress toward SDG 15 (Life on Land), SDG 2 (Zero Hunger), and SDG 13 (Climate Action), emphasizing that food security and ecosystem health must go hand in hand.'', he concludes.
The study was enabled by a Jennifer Ward Oppenheimer Research Grant, which supports young African researchers in developing solutions to African challenges.
Research article: Clements, H., R. Biggs, A. De Vos, E. Do Linh San, G.P. Hempson, B. Linden, B. Maritz, A. Monadjem, C. Reynolds, F. Siebert, N. Stevens, M. Child, E. Di Minin, K. J. Esler, M. Hamann, T. Loft, B. Reyers, O. Selomane, G. Singh & A.L. Skowno . A place-based assessment of biodiversity intactness in sub-Saharan Africa. Nature (2025).