Africa’s Ecosystems Are Becoming Increasingly Alike, Study Finds

Africa’s ecosystems may appear very different, yet a new study indicates that they are growing increasingly similar.

Researchers found that mammal food webs across Africa most closely resemble one another in protected areas that have comparable levels of plant growth.

The results indicate that ecosystems may converge in the way they operate even if they are home to different animals.

Ecological patterns across Africa

The convergence emerged in the feeding connections that mammal communities could sustain across 127 protected areas, ranging from dry regions to rainforests.

Lydia Beaudrot of Michigan State University and her colleagues recorded this trend in the organisation of local food webs.

Locations with comparable quantities of vegetation consistently generated similar food-web structures, despite supporting different sets of species.

This result pointed to ecosystem function, rather than an overlap in species, as the key issue and raised the question of what produces this common structure.

Energy at the foundation of food webs

Plant growth underpinned the trend, as all herbivores and predators rely on energy captured by vegetation.

Ecologists refer to this resource as primary productivity: the rate at which plants convert sunlight into living material that animals can use.

Where two locations generated similar volumes of vegetation, their food webs were more likely to contain a similar balance of prey, grazers and predators.

“The amount of energy available ultimately controls the amount of vegetation in a system,” said assistant professor Beaudrot.

Congo Basin forests under pressure

A single region departed from the broader continental pattern: the immense tropical forests of the Congo Basin.

At ten forest locations, comparable habitat fragmentation - where human land use divides habitat into separate pieces - was associated with increasingly similar food webs.

These sites were located within a region of roughly 3.6 million square kilometres, but even relatively limited fragmentation corresponded with similar shifts in the networks.

The findings indicated that human disruption was having a predictable effect there, creating a more explicit warning for conservation.

Similar roles, different animals

Species identities did not alone explain the pattern, because the team compared positions within the networks rather than depending solely on species lists.

A leopard and a hyena are distinct animals, yet food webs may still be alike if predators fill comparable roles within them.

This approach made the research particularly relevant across a continent where sites can share ecological functions without containing the same mammals.

Conservation strategies based only on species lists may therefore overlook this less obvious decline in structure and function.

What fragmentation affects first

Fragmentation affects more than the area of habitat available: it alters which animals can travel, hunt, shelter and breed in a divided landscape.

Because large mammals commonly require extensive ranges, roads, farms and settlements may remove top predators from local interactions before other species are affected.

“Protected areas are critical strongholds for conservation,” said Beaudrot, whose team followed changing predator-prey connections within formally protected landscapes.

As similar types of species disappear from separate forests, ecosystems may begin to function in the same more restricted manner.

The limits of protection

Protected status reduced some of the harm, but it did not isolate these communities from surrounding agriculture and development.

Most Congo Basin sites still experienced little direct human land use, meaning that modest changes were detectable before a complete collapse occurred.

“At the same time, the wildlife they’re trying to protect are not immune to the effects of human encroachment,” said Beaudrot.

Reserve boundaries may remain intact on maps even while the feeding relationships within them keep shifting, which makes conservation success more difficult to assess.

Study limitations

Nevertheless, the pattern had limitations that prevented the authors from presenting it as a complete account of ecological change.

Their maps showed where species occurred rather than the numbers that remained, allowing declining populations to go undetected by the analysis.

Calculating average vegetation and land use over 20 years also obscured sudden disturbances that may have affected animals immediately.

These omissions are likely to understate rather than exaggerate the concern, since food webs can deteriorate before extinctions become apparent.

Why large mammals matter

This issue is especially significant for large mammals because, even across different species, they disperse seeds, influence vegetation, distribute nutrients and regulate prey.

When these connections shift, forests may store carbon in different ways, plants may regenerate differently and smaller animals may increase without control.

Africa provides an unusual opportunity to monitor food-web change because one continent encompasses deserts, woodlands and tropical rainforests.

That breadth enabled the researchers to compare highly different habitats without reducing the issue to one famous species.

Practical choices for conservation

Land managers cannot rapidly alter rainfall or sunlight, but they can reduce the fragmentation that reconfigures these networks.

Maintaining connections between forest blocks, restricting the spread of roads and creating buffers between reserves and cropland could help retain more distinctive food webs.

The urgency arises from a straightforward threat: if comparable pressures remove different ecological roles, many reserves could begin to operate in similar ways.

A park may remain green and appear rich in animal life while losing the pattern of interactions that gives it resilience.

The study found that Africa’s ecosystems can converge because of shared energy conditions and, in rainforests, because of shared human disturbance.

Future monitoring that includes population numbers and additional animal groups should show how early this convergence starts and the extent to which it can be reversed.