Understanding the Scale of Primate Loss in Sub‑Saharan Africa
In December 2025, a landmark study published in Nature highlighted that Sub‑Saharan Africa has lost up to half of its primate populations since pre‑industrial times. The research, led by Dr. Birthe (Bibi) Linden of Aberystwyth University, combined the expertise of 200 African ecologists to produce the most comprehensive assessment of biodiversity intactness in the region to date.
Aberystwyth University’s contribution underscores the university’s role in ecological expertise and biodiversity conservation across the UK and beyond. By integrating local knowledge with global data, the study offers a realistic picture of how human activities are reshaping ecosystems.
Methodology: The Biodiversity Intactness Index (BII)
The team employed the Biodiversity Intactness Index, a metric that measures the proportion of original biodiversity remaining in a landscape. Unlike many global assessments that rely on sparse data, the BII for Africa was built from regional ecological expertise, ensuring that African conditions are accurately represented.
Key steps included:
- Collecting species abundance data from field surveys and long‑term monitoring sites.
- Mapping land‑use changes, particularly cropland expansion, across different ecosystems.
- Calculating average declines for plant and animal groups, with a focus on large mammals and primates.
Findings: A Deepening Crisis for Primates
Primate species—applies to apes, monkeys, galagos, and lorises—experienced the third‑largest decline after large herbivores and carnivores. Rainforest primates lost over 50% of their historical abundance on average, while woodland and savanna species fell by at least one third.
Large mammals such as elephants, lions, and certain antelope species suffered losses exceeding 75% of their historical numbers. In contrast, plant species that can withstand environmental disturbances showed smaller declines, around 10%.
Drivers of Decline: Cropland Expansion and Chemical Use
Cropland expansion emerged as the primary driver of biodiversity loss. Intensive farming reduces habitat diversity and increases chemical inputs, further stressing wildlife. With cropland projected to double and cereal demand to triple by 2050, the study stresses the need for biodiversity‑positive farming practices that balance food security with ecosystem health.
Beyond Protected Areas: The Importance of Community Landscapes
More than 80% of the region’s remaining wild plants and animals live outside formally protected lands. These landscapes support over 500 million people and provide essential ecosystem services such as clean water, pollination, and carbon storage. The study highlights that conservation strategies must extend beyond protected areas to include these community‑managed ecosystems.
Implications for Policy and Conservation
Aberystwyth University’s research equips policymakers and conservationists with data needed to safeguard ecosystems beyond protected zones. By bridging knowledge gaps with regional expertise, the study lays a foundation for informed decisions that balance development and biodiversity, ensuring a more sustainable future for the continent.
Explore Aberystwyth University’s research programs and learn how you can contribute to global biodiversity conservation.
How You Can Get Involved
Whether you are a student, researcher, or environmental advocate, there are several ways to support the work highlighted in this study:
- Join Aberystwyth University’s conservation initiatives and volunteer in field projects.
- Participate in citizen science programs that monitor primate populations.
- Advocate for sustainable agricultural practices in your community.
Contact the Department of Life Sciences to find out how you can collaborate on future research.
For more detailed insights, read the full study in Nature or visit the project website at BII4Africa.
Stay informed about ongoing research by subscribing to Aberystwyth University’s news updates.
