By Abdullahi Lukman
Biodiversity decline has sharply reduced the functioning of ecosystems in sub-Saharan Africa, with the loss of birds and small mammals significantly weakening key ecological processes, according to a new study published in Nature.
The research shows that the “ecological power” of wild birds and mammals — the energy driving functions such as pollination, seed dispersal and pest control — has fallen by about 60 percent in areas converted to agriculture. In contrast, well-managed protected areas retain nearly 90 percent of their ecological functions.
Led by conservation biologist Ty Loft of the University of Oxford, the study analyzed nearly 3,000 bird and mammal species across the region.
Researchers assessed how these species contribute to 23 ecosystem functions by measuring energy flows based on species abundance, body size, diet and metabolic rates, using the year 1700 as a historical baseline.
Unlike traditional approaches that track only changes in species numbers, the study grouped animals by ecological roles and calculated how much energy they consume and transfer within ecosystems.
This method highlights the functional importance of species, including smaller animals such as birds and rodents that process energy rapidly despite their size.
The findings reveal that birds and small mammals play a much larger role in ecosystem functioning than previously assumed, while the decline of megafauna such as elephants has severely reduced ecological processes outside protected areas.
Independent experts described the approach as innovative, noting that it allows comparison of species based on their functional impact rather than size or biomass alone.
However, they cautioned that the method relies on extensive datasets and assumptions, and may not capture all ecosystem changes or guide site-specific management decisions.
Despite these limitations, researchers said the results provide a clearer picture of large-scale ecological change and could help inform conservation priorities, restoration efforts and decisions on which species and areas to protect or reintroduce first.
