A landscape designed for exploration

• Scientists achieved horse pregnancies using embryos created entirely in laboratories and transferred after freezing – a process that could be beneficial for the conservation of rhinos.
• Horses provide a crucial research model because rhinos share similar reproductive biology and embryo characteristics.
• Assisted reproductive technologies could help move genetic material between isolated rhino populations without translocation.
• Cryopreservation allows sperm, eggs and embryos to be stored long-term, preserving genetics beyond an animal’s lifetime.
• Researchers hope to produce white rhino calves from lab-created embryos as reproductive science advances.

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Groundbreaking advances in lab-grown embryos are opening a new frontier in rhino conservation by allowing scientists to safeguard and expand the species’ fragile gene pool. By perfecting complex reproductive technologies in horses – rhinos’ closest domestic relatives – researchers are building the genetic tools that could help secure the future of one of Africa’s most threatened megafauna.

When a team of researchers recently achieved pregnancies in horses using embryos produced entirely in the lab and transferred after freezing, it signified a leap in assisted reproductive technologies to support genetic diversity in rhino populations.

The achievement by the University of Pretoria’s Faculty of Veterinary Science Department of Production Animal Studies and Hemmersbach Rhino Force – a first for South Africa – illustrates how techniques developed in domestic animals may eventually support endangered species such as African rhinos.

Inside the science of lab-grown embryos – and what it could mean for rhinos

Researchers collected eggs from live and euthanised horses, matured them in the laboratory and fertilised them using intracytoplasmic sperm injection (ICSI). The resulting embryos were cultured to the blastocyst stage, frozen, thawed and transferred into recipient mares, demonstrating that the full laboratory-to-pregnancy process can be performed in South Africa.

The deeper significance of the achievement, which took place in late 2025, lies in the complex chain of technologies required to make it work, and how those processes are now being refined with conservation in mind.

The horse provides a useful model for developing reproductive technologies intended for rhinoceroses. Both animals belong to the mammalian order Perissodactyla, which includes odd-toed hoofed mammals.

Because of this relationship, eggs and embryos from horses and rhinos share similar characteristics and respond to similar laboratory conditions during embryo culture.

“The horse is the closest domestic relative of the rhino belonging to the same order,” explains Rhino Force’s veterinarian Dr Janine Meuffels-Barkas. “Oocytes and embryos have similar characteristics and requirements in the in vitro embryo production process.”

Working with horses also allows researchers to refine techniques more rapidly. Domestic animals are more accessible and can be handled repeatedly, which makes it possible to test protocols and optimise laboratory procedures before applying them to endangered wildlife.

“After the success of in vitro embryo production in horses, we plan to test our protocols in rhinos and adapt where needed. We have already successfully conducted egg aspirations in more than 40 females,” says Meuffels-Barkas. “We plan to improve the detection of the stage of the female’s reproductive cycle to identify the correct time for embryo transfer.”

Meuffels-Barkas says the team hopes to repeat all processes successfully in white rhinos to produce live calves from in vitro produced embryos.

The potential of assisted reproductive technologies has already been demonstrated in efforts to rescue the northern white rhino. Scientists working with the BioRescue consortium have successfully produced laboratory-created embryos using eggs collected from the last surviving females, Najin and Fatu, and frozen sperm from deceased males. These embryos have been cryopreserved and are intended for future transfer into southern white rhino surrogate mothers. While a live birth has not yet been achieved, the work has shown that rhino embryos can be created outside the body, providing a possible pathway to revive a functionally extinct subspecies.

Assisted reproduction in the conservation toolkit

Conservation strategies for rhinos currently rely heavily on anti-poaching efforts, habitat protection and the management of protected populations. Assisted reproductive technologies add a complementary set of tools.

Techniques such as artificial insemination and embryo transfer allow genetic material to move between populations without transporting the animals themselves. This can help maintain genetic diversity in populations that are geographically isolated.

“Assisted reproductive technologies allow us to enrich isolated wildlife populations with new genetics without the necessity of moving animals and facing all the logistical and adaptation problems associated with translocation,” says Meuffels-Barkas.

Genetic diversity is a major concern for rhinos. When populations decline sharply, they can experience a genetic bottleneck – a reduction in genetic variation caused by a dramatic drop in population size.

White rhinos experienced such a bottleneck in the late 1800s when hunting reduced their numbers to fewer than 100 individuals. The present-day population descends from those survivors, meaning the gene pool is already limited.

Why horses require a different fertilisation method

In many mammals, embryos can be produced through conventional in vitro fertilisation, where sperm and eggs are combined in a laboratory dish. Horses present a particular challenge because standard IVF rarely results in successful fertilisation.

For this reason, Intracytoplasmic Sperm Injection (ICSI) has become the preferred method for producing equine embryos in vitro. The technique allows embryologists to bypass the biological barriers that normally prevent sperm from fertilising the egg under laboratory conditions.

The procedure is technically demanding. It requires specialised equipment, highly trained embryologists and carefully optimised culture conditions that allow embryos to continue developing outside the body.

According to Meuffels-Barkas, one of the most important breakthroughs was establishing the laboratory conditions required for embryo growth.

“The in-vitro embryo production, including the ICSI procedure as well as identifying the correct media and protocols to grow the embryo to the blastocyst stage were the biggest breakthrough,” she says.

Preserving genetics beyond the animal’s lifetime

One advantage of laboratory embryo production is the flexibility it introduces to reproduction. Eggs and sperm can be collected at different times, fertilised in the laboratory and the resulting embryos frozen for future use.

Cryopreservation plays a key role in this process. Biological material such as sperm and tissue samples can be stored in liquid nitrogen at −196 °C, a temperature that effectively halts cellular activity while preserving viability.

Postmortem collection of reproductive material expands the value of these archives. If eggs or sperm remain viable after an animal’s death, they can still be used to produce offspring.

This ability to preserve genetics beyond an animal’s lifetime is particularly important for conservation.

CryoVault – building a genetic archive for rhinos

The work also connects to Hemmersbach Rhino Force’s CryoVault project – a biobank dedicated to preserving viable biological material from African rhinoceroses as a form of long-term “genetic back-up”.

Since 2018, the CryoVault team has been collecting and cryopreserving semen and other biomaterials from rhinos during routine wildlife management procedures such as dehorning or ear-notching, when animals are already immobilised. To date, viable semen samples from more than 40 free-ranging and game-farmed black and white rhinos have been preserved, alongside tissue and blood samples.

The programme has since expanded to include female genetics. Using ovum pick-up techniques, researchers have collected eggs from more than 40 female white rhinos as part of a collaboration with the University of Pretoria to produce rhino embryos through assisted reproductive technologies.

By storing sperm and other biological material, and potentially embryos in the future, in liquid nitrogen at −196 °C, the CryoVault effectively creates a long-term genetic reservoir. These preserved samples could one day be used to strengthen genetic diversity in rhino populations through artificial insemination, embryo production and embryo transfer.

The hurdles still facing rhino reproduction

Although the technology works in horses, several scientific hurdles remain before it can be applied successfully to rhinoceroses.

Researchers must first learn how to culture rhino embryos reliably in the laboratory. Even small differences between species can affect how embryos respond to culture conditions.

Another challenge is transferring embryos safely into surrogate females. Embryo transfer requires precise timing within the female’s reproductive cycle so that the uterus is ready to support implantation.

Monitoring that cycle in wild or semi-wild rhinos remains technically difficult. Researchers must also account for the long rhino gestation period, which lasts about 16 to 18 months.

Despite these challenges, progress is continuing. The team plans to test the refined laboratory protocols developed through equine research in rhino oocytes collected going forward.

The long-term objective is to produce rhino calves from embryos created outside the body – extending the role of reproductive science in safeguarding the species’ future.

Further reading

• The rhino Cryovault – frozen in time: If all the money, time, blood and sweat fail to save our wild rhinos, Hemmersbach has a solution. The rhino Cryovault stores repositories of rhino DNA, gametes, and tissues, preserving them indefinitely. Read more here
• Hornless hope – is rhino dehorning the most effective tool in saving the species? Rhino dehorning slashes poaching by 78% – a bold, effective strategy that challenges how we think about wildlife crime prevention
• Rhino Rewild – is this the most critical wildlife conservation undertaking of our time? Simon Espley attended the pioneer stage of a visionary project to translocate 2,000 farmed rhinos into the wild. Here’s how it went down
• Can rhinos survive climate change? Unable to cope well with prolonged periods of extreme temperatures, rhinos are particularly vulnerable to the increasing heat associated with climate change. Read more here

• Impalas near high-infrastructure Serengeti lodges showed higher stress hormone levels than those near lighter camps.
• Lodge infrastructure was linked to elevated stress even when no tourists were present.
• Tourist numbers increased stress at tented camps, especially when occupancy limits were exceeded.
• Better forage quality reduced stress, showing habitat condition can buffer tourism pressure.
• Larger impala groups had lower stress, suggesting social living helps reduce perceived risk.

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Tourism keeps protected areas running, but a recent study reveals a trade off. In Serengeti National Park, impalas living near high-infrastructure lodges had higher stress levels than those near lighter-footprint camps – even when no tourists were present. The message is direct: in some cases, the infrastructure itself is part of the problem.

Tourism sustains many of Africa’s protected areas. Entrance fees, accommodation, and related services generate funds that support conservation management, research and anti-poaching efforts. Globally, protected areas receive an estimated eight billion visits each year and generate around USD 600 billion in tourism revenue. In many developing countries, this income is essential for maintaining biodiversity.

At the same time, tourism brings infrastructure. Lodges, camps, roads and other facilities are built to accommodate visitors. When development expands faster than ecosystems can absorb, wildlife can be affected. A recent study published in Global Ecology and Conservation from Serengeti National Park in Tanzania examined whether tourism infrastructure itself influences the physiological stress levels of wild animals.

The research focused on impalas (Aepyceros melampus), a common antelope species widely distributed across eastern and southern Africa. Impalas are considered a useful indicator species for studying human disturbance because they respond physiologically to environmental change. By measuring stress hormones in impalas living near different types of tourist accommodation, researchers assessed how tourism infrastructure may affect wildlife even inside a protected area.

Tourism growth in the Serengeti

Serengeti National Park covers about 14,700 km² and supports one of the world’s most diverse wildlife ecosystems. It is home to millions of ungulates, including wildebeest and plains zebra, and large predators such as lions, cheetahs and hyenas.

Tourism in the Serengeti has expanded rapidly in recent years. According to park records, permanent accommodation facilities increased from about 15 in 2014 to around 50 in 2024, with a further 25 facilities under development. Non-permanent campsites also increased, rising from 98 sites in 2014 to 218 sites by 2024.

Previous research has shown that tourism infrastructure can alter wildlife behaviour. In the Serengeti, lodge construction done without sufficient planning has already been linked to changes in the movement patterns of the wildebeest migration. Other studies elsewhere have shown animals avoiding areas with tourism infrastructure or changing behaviour near tourist roads.

This is not the first warning sign. UNESCO and IUCN recently raised concern over proposed expansion of tourism infrastructure in Serengeti National Park, including sharp increases in lodges and permanent tented camps, while their 2024 reactive monitoring work also reviewed developments such as the Fort Ikoma golf course, the proposed Mugumu airport and additional lodge projects. The wider concern is cumulative impact – especially where infrastructure growth begins to squeeze habitat, water resources and movement routes in one of Africa’s most important migratory ecosystems.

The new study aimed to understand whether tourism facilities influence wildlife in another way – through physiological stress.

Measuring stress in wildlife

Stress in animals is often measured through glucocorticoids. These hormones are part of the body’s endocrine response to challenging conditions such as disturbances, resource scarcity, or environmental pressures. Elevated glucocorticoid levels can indicate physiological stress and may affect reproduction, survival and behaviour.

Researchers increasingly measure these hormones using faecal glucocorticoid metabolites (FGMs). FGMs are hormone breakdown products that can be detected in animal dung. This method allows scientists to assess stress levels without capturing or handling animals, avoiding additional disturbance.

FGM analysis reflects activity of the hypothalamic–pituitary–adrenocortical axis, which regulates hormonal stress responses. Because these metabolites accumulate over time, they provide an integrated measure of stress rather than short-term fluctuations.

Why impalas are useful indicators

Impalas are medium-sized antelopes common in the Serengeti ecosystem, where their population exceeds 85,000 individuals. They live in social groups that can include female herds, bachelor groups or solitary territorial males. As mixed feeders, impalas graze grasses in the wet season and browse shrubs during the dry season. They typically remain within relatively small home ranges and are prey for large carnivores such as lions and hyenas.

Their abundance, social structure and sensitivity to human disturbance make them useful for studying how environmental factors affect wildlife physiology in protected areas.

Collecting stress data in the Serengeti

Researchers collected 213 faecal samples from impalas between January and February 2025, during the Serengeti’s wet season, when forage quality is high. The sampling period also coincides with high tourist visitation.

Samples were collected from animals located within one kilometre of different types of tourist accommodation: lodges, permanent tented camps and seasonal campsites. Researchers recorded information about each impala group, including behaviour, group size, time of day and environmental conditions.

To isolate the effect of tourism infrastructure, the analysis also considered other factors that may influence stress levels. These included forage quality, measured using the Normalised Difference Vegetation Index (NDVI), and land surface temperature.

NDVI is a satellite-based measure of vegetation productivity. Higher NDVI values indicate greener and more productive vegetation, which generally reflects better forage quality for herbivores.

Infrastructure linked to higher stress in Serengeti

The analysis revealed clear differences between accommodation types.

Impalas living near larger lodges showed significantly higher levels of stress hormones than those near permanent tented camps or seasonal campsites. According to the study, “impalas near permanent tented camps and seasonal campsites had significantly lower FGM levels compared to those near lodges.”

The effect remained even when lodges had no tourists present. The researchers concluded that “larger facilities, such as lodges, were associated with increased stress levels even when there were no visitors.”

The likely explanation is infrastructure scale. Larger tourism facilities typically require more extensive buildings, roads and service areas than tented camps or seasonal campsites.

The role of tourist numbers in the Serengeti

The study also examined tourist occupancy. Higher tourist numbers increased stress levels around tented camps and campsites, especially when visitor limits recommended by the Tanzania National Parks Authority (Tanapa) were exceeded.

Permanent tented camps in the Serengeti have an official occupancy limit of 50 tourists, while seasonal campsites are limited to 20. The researchers found that when these limits were exceeded, the effect of tourist numbers on impala stress became stronger.

This suggests that both infrastructure and visitor numbers contribute to physiological pressure on wildlife. Importantly, it suggests that obeying occupancy limits set by Tanapa is essential to the preservation of ecosystems.

Environmental factors also matter

Other ecological factors influenced stress levels.

Impalas living in areas with higher vegetation productivity showed lower stress levels. The study found that FGM levels declined as NDVI increased, indicating that better forage conditions can buffer physiological stress. Access to nutrient-rich vegetation likely allows animals to maintain better physical condition and allocate more energy to feeding and reproduction rather than coping with disturbance. In productive landscapes such as the Serengeti during the rainy season, high-quality forage may therefore help mitigate some of the stress associated with tourism infrastructure.

Group size also played a role. Impalas in larger herds had lower stress levels than those in smaller groups. Living in larger groups may reduce perceived predation risk and allow individuals to spend more time feeding.

Behaviour during sampling was also associated with hormone levels. Individuals who were walking showed higher FGM levels than those who were feeding.

Implications for protected area management and tourism

The study highlights the complex relationship between tourism development and wildlife conservation.

Tourism provides essential revenue for protected areas, yet the infrastructure required to support large tourist operations can affect wildlife physiology. In this case, large tourism facilities were linked to elevated stress levels in impalas.

This is why lodge choice matters. The study shows that large, fixed infrastructure can increase wildlife stress even in the absence of guests, which means tourism should not be judged solely by visitor numbers but by footprint, placement, and design. In a landscape defined by movement, developments that obstruct migration paths, intensify habitat pressure or sit outside careful environmental planning can undermine the ecological systems that tourism depends on. Well-planned lodges and camps, strong environmental impact assessments, low landscape disturbance and tourism partners aligned with conservation objectives are therefore not optional extras – they are central to keeping protected areas functional and wildlife populations secure.

The authors conclude that managing tourism development is essential to balance conservation and economic benefits. Maintaining visitor limits at campsites and tented camps could help reduce pressure on wildlife.

The study also calls for further research to identify which specific aspects of lodge infrastructure contribute most strongly to wildlife stress. Understanding these mechanisms could help guide future tourism planning in protected areas such as the Serengeti.

Reference

Kessy, B.M., Arukwe, A., Mbise, F.P., Hariohay, K.M., Palme, R., Røskaft, E. & Ranke, P.S., 2026. Tourism infrastructure and physiological stress in free-ranging impalas (Aepyceros melampus) of Serengeti National Park. Global Ecology and Conservation, 67, e04130.

Further reading

• For decades, only alpha female wild dogs were believed to breed.
• Long-term Zimbabwe data challenges the dominant-only breeding model.
• Subordinate females produced nearly a quarter of litters.
• Second litters did not reduce pup survival rates.
• Social structure, not climate, shaped reproductive patterns.

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For decades, many field guides and safari narratives have repeated a simple rule: in an African wild dog pack, only the alpha female breeds. This view was shaped in part by Hugo van Lawick’s 1974 account Solo, which documented aggression by an alpha female toward a subordinate that had given birth. That account suggested strict reproductive control, including infanticide and starvation of subordinate females.

But new long-term research from Zimbabwe challenges that assumption. A 14-year study in the Savé Valley Conservancy, Zimbabwe, analysed reproduction in 49 packs of African wild dogs Lycaon pictus, across 131 den sites. The findings show that, at least within this landscape, subordinate females breed far more often than previously assumed – and that their pups survive at comparable, and sometimes higher, rates. The research was conducted by the African Wildlife Conservation Fund in collaboration with the London Zoological Society, Rhodes University, University of Mpumalanga and the Zimbabwe Parks and Wildlife Management Authority.

What cooperative breeding means

Cooperative breeding occurs when individuals other than the parents help raise young. It is rare in mammals, found in less than 1% of species.

In wild dogs, cooperative breeding is considered near-obligate. Packs typically consist of an alpha pair, subordinate adults and offspring. During the approximately three-month denning period, all adults regurgitate food for the lactating female and pups.

Two evolutionary concepts help explain this system. Kin selection refers to individuals increasing their inclusive fitness by helping relatives reproduce. Group augmentation refers to the benefits of living in larger groups, such as improved hunting success and pup survival. In wild dogs, larger packs are known to raise more pups to independence. The new study examines how these social and ecological factors interact.

Subordinate females breed more often than assumed

Between 2008 and 2021, the 49 packs studied in the Savé Valley study area produced 130 breeding events and 173 litters. Of these packs, 20 produced multiple litters, with two females from the same pack breeding during the same denning season. Among packs capable of doing so – those with more than one breeding-age female – 41.15% of breeding events resulted in multiple litters.

Subordinate females contributed 24.86% of all litters. Importantly, their pups accounted for 32.19% of one-year survivors and 33.68% of two-year survivors. Infanticide was rare. It occurred in 2% of multiple-litter packs, while pup stealing or adoption occurred in 14%

These figures contrast with earlier assumptions that dominant females frequently suppress subordinate reproduction through killing pups. The study therefore shows that subordinate breeding is not exceptional in this population and does not generally result in severe reproductive conflict.

What drives multiple litters

The researchers tested whether environmental conditions, such as rainfall and temperature, influenced the occurrence of multiple litters. Pre-emergence rainfall and temperature can affect prey availability and hunting success, which, in turn, influence the energy available for reproduction. However, statistical models showed that environmental variables did not predict whether a pack produced multiple litters.

Instead, social structure was decisive. Younger packs were significantly more likely to produce multiple litters. Packs with more subordinate females were also significantly more likely to do so. Pack age had a significant negative effect on the probability of multiple litters, while the number of subordinate females had a significant positive effect. The authors conclude that weaker dominance hierarchies in younger packs may allow more subordinate breeding. This supports the idea that reproductive sharing is shaped by social dynamics rather than short-term environmental variation.

Do second litters survive?

When two litters are born in the same pack, pups may be first-born or second-born. A common assumption is that second-born pups would suffer from competition for food, or from leaving the den too early, with the second-born pups being too small to survive moving with the pack.

The data do not support these assumptions. Within multiple-litter packs, pup survival to one year was significantly higher for second-born litters than for first-born litters. By the second year, survival did not differ by birth order.

Across all packs, a larger pack size significantly improved both one-year and two-year survival. Two-year survival also increased with higher pre-emergence rainfall and higher maximum daily temperatures. These findings indicate that communal care can buffer potential disadvantages associated with birth order. In addition, pups from single-litter packs had significantly lower survival to two years compared to pups from multiple-litter packs. The data show that cooperative systems can enhance long-term survival.

Related females and reproductive tolerance

In multiple-litter packs, breeding females were often closely related. The most common relationship was litter sisters, accounting for 37.21% of cases. Mother–daughter pairs and other related combinations were also recorded.

High relatedness may reduce conflict. Kin selection theory predicts that females may tolerate reproduction by relatives because they share genes.

The authors note that the tolerance of multiple litters may also affect genetic diversity in the Savé Valley population, which is known to exhibit low genetic diversity. Allowing more females to breed could increase genetic contribution within packs.

The bigger conservation picture

African wild dogs persist in only 7% of their historic range. They face habitat fragmentation, prey decline, human–wildlife conflict and climate change. This study shows that subordinate breeding does not reduce pup survival and that multiple-litter packs have higher two-year survival rates.

It also shows that social structure, particularly pack age and the presence of subordinate females, shapes reproductive outcomes.

For conservation practitioners, the implication is clear. Maintaining intact social structures and sufficient pack size is important. Suppressing subordinate breeding is unlikely to benefit population growth in this system.

The long-held belief that only alpha females breed does not hold in this population. Cooperative breeding in African wild dogs can be more flexible in certain populations, more tolerant and more productive than once assumed.

Reference

• Groom, R.J., Comley, J., Wolton, A., Ngwenya, N., Mandisodza-Chikerema, R. and Watermeyer, J.P. (2026), Exploring the complexities of cooperative breeding: insights from African wild dog packs. J Zool, 328: 16-29.

Further reading

• Longing to see African wild dogs? Here are the six best spots to see painted wolves in Africa – for your next safari with us.
• Tsavo’s African wild dogs face major threats. Tsavo Trust & Painted Wolf Foundation are working to save these painted dogs. Here’s how
• Could we double African wild dog (painted wolf) numbers by 2050? With funding, collaboration and recovered territory, it’s possible. Learn more here
• To learn more about this research or to support the work around the wild dogs mentioned in this article, visit African Wildlife Conservation Fund’s website here.

Questions such as these will be the focus of a presentation delivered at the African Wild Dogs United 2026 Virtual Conference, March 10–12. Across three days, 78 presentations will examine a wide range of African wild dog research topics. Everyone interested in, passionate about, or fortunate enough to have spent time with African wild dogs is invited to peruse the programme, explore the list of keynote speakers, register, support a student and make a donation via AWDU. The African Wild Dog Survival Fund is sponsoring the three days, enabling registration revenue to be channelled into bursaries for young aspiring Africans wanting to work with wild dogs.

• Africa’s wildlife energy flows have dropped by over one-third since 1700.
• Ecosystem functions declined sharply as birds and mammals lost ecological power.
• Agricultural conversion reduced ecological power by about 60% across sub-Saharan Africa.
• Protected areas retained nearly 90% of animal-driven ecosystem functions and energy flows.
• Megafauna-driven grazing, browsing and nutrient cycling collapsed outside protected landscapes.

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Africa’s wildlife is doing far less ecological work than it once did. A new study suggests that the decline of birds and mammals – and in particular megafauna such as elephants – is reshaping how ecosystems function. By looking beyond species counts to the energy animals move through landscapes, researchers uncover a deeper shift – one that has implications for how Africa’s ecosystems are changing, and what still remains intact. By measuring energy flows, the researchers show that wildlife decline is draining Africa’s landscapes of ecological power, especially outside protected areas.

A study published in Nature has put a number to something conservationists have long suspected – Africa’s wildlife decline is not only a matter of losing species, but of losing ecological function.

Using an approach based on ecosystem energetics, the researchers found that energy flows through bird- and mammal-driven ecosystem functions across sub-Saharan Africa have declined by more than one-third. In practical terms, the continent has lost a substantial portion of the “ecological power” that animals once provided through feeding, movement, and ecological interactions.

The decline is uneven across land uses, and particularly severe outside of protected areas.

Measuring energy flow

Most large-scale biodiversity indicators track how many species remain, or how their populations have changed. But these measures can be blunt. They treat all species as equal, even though ecosystems do not work that way. A small insect-eating bird and an elephant may both count as “one species”, but they do not contribute equally to how ecosystems function.

To address this, the authors used energy flow as a common currency. Energy is captured by plants and then transferred up the food web as animals feed. The amount of food an animal consumes is a measurable proxy for its ecological influence – because consumption drives grazing pressure, predation, seed dispersal, nutrient cycling, and many other processes. In this study, energy flow was calculated as the annual food energy consumed by each species per unit area.

The dataset behind the results

The researchers analysed 1,088 mammal species and 1,955 bird species – nearly 3,000 species in total, representing 98% of Africa’s bird and mammal species (excluding seabirds). They modelled historical energy flows under conditions around 1700 CE, a time before major colonial and industrial land transformation had begun, and compared these with modern energy flows shaped by today’s land uses.

To do this, they analysed species range maps, population densities, body size and diet traits, metabolic equations estimating energy expenditure, and biodiversity intactness estimates describing how species abundances change under different land uses. They then grouped species by ecological role, identifying 23 functional groups (11 bird and 12 mammal functions), which were later aggregated into 10 major ecosystem functions.

These functions included grazing and browsing, insectivory (the ecological function of eating insects), seed dispersal, pollination, scavenging, nutrient dispersal, and carnivory (the consumption of animal tissue).

The key result: Africa’s ecological power has dropped sharply

Across sub-Saharan Africa, the total energy flow through wild birds and mammals has dropped to 64% of historical levels. That means roughly 36% of animal-driven ecological energy has been lost. This decline is not just a biological statistic. It indicates weakening ecological processes, because the animals that drive these processes are consuming less energy overall – either because their populations are smaller, they have disappeared from certain landscapes, or they have been replaced by smaller species with different ecological roles.

Land conversion has the strongest effect

The study found that energy flows fell dramatically in areas converted to intensive human land uses:

• Settlements: 27% of historical energy flow remaining
• Croplands: 41% remaining
• Unprotected untransformed lands (rangelands and near-natural lands): 67% remaining
• Strict protected areas: 88% remaining

Croplands and cities were responsible for 25% of the total decline in energy flows across the region. This result links land use change directly to ecosystem function. It suggests that agriculture and urban expansion are not only shrinking wildlife populations – they are reshaping how ecosystems operate.

Protected areas still retain most ecological function

One of the study’s strongest messages is that well-managed protected areas preserve ecological function far better than surrounding landscapes. Strict protected areas retained 88% of historical energy flows. This does not mean protected areas are unchanged, but it does mean that many animal-driven ecosystem functions remain close to intact when wildlife populations are maintained.

The collapse of megafauna functions

The steepest declines were seen in functional groups dominated by megafauna. Large herbivores – including grazers, browsers, and frugivores – historically accounted for more than one-quarter of mammalian energy consumption. Their energy flows have decreased by 72%.

The paper highlights that energy flows through megafauna-dominated functions such as nutrient dispersal, grazing and browsing, and apex carnivory are only 26–32% intact across the region. These are not minor ecosystem roles. Megafauna shape vegetation structure directly through feeding and nutrient release, and indirectly through predator–prey regulation.

Because 80% of Africa is classified as unprotected untransformed land, the wildlife decline, particularly of large herbivores and carnivores, may be altering vegetation patterns at a continental scale.

Small animals are becoming more dominant

While megafauna functions collapse, the study shows that African ecosystems are increasingly dominated by smaller species. The proportion of energy consumed by small birds and mammals increased from 69% historically to 78% today. Meanwhile, megafauna (>65 kg) fell from 16% of total energy flow to just 7%.

Passerine birds, including many of Africa’s songbirds, accounted for 8% of historical energy consumption but only 2% of total biomass, indicating that small species play outsized ecological roles. But small animals cannot fully replace the ecological roles of large animals. The authors note that smaller species do not compensate for attributes such as “large seed dispersal and greater daily transport ranges” that are unique to larger wildlife.

In other words, ecosystems may retain activity, but lose key ecological functions that depend on body size and movement across landscapes.

Key functions are disappearing outside protected areas

Some ecosystem functions show particularly steep declines.

Seed dispersal and pollination are highlighted as important examples. Seed dispersal is critical because many plants rely on animals to transport seeds away from parent trees, allowing forests and woodlands to regenerate and maintain diversity. Pollination is equally essential for reproduction in many plant species.

The study found that energy flows through seed dispersers are only 58% intact in untransformed lands, and 14% intact in croplands.

Pollination energy flows were 63% intact in untransformed lands and 25% intact in croplands.

These declines suggest that even where vegetation remains, the animal-driven processes that support plant reproduction and recovery may be severely weakened by wildlife declines.

Changes in how biodiversity loss is measured

The researchers argue that traditional measures of biodiversity intactness may overlook substantial functional losses because they treat all species as equally important.

Energy-based analysis changes the picture by showing which species and functional groups carry the most ecological weight.

This approach revealed that biodiversity intactness indices “substantially overestimate the intactness of the megafauna-performed functions”.

In other words, ecosystems may still appear moderately “intact” by standard biodiversity measures, even while critical large-animal functions have collapsed.

The bottom line

This study quantifies a continent-wide erosion of ecosystem function by tracking energy flows through nearly 3,000 bird and mammal species across sub-Saharan Africa. Its most important conclusion is stark: the ecological power of Africa’s wildlife has declined by more than one-third. In croplands and settlements, that decline is catastrophic. In protected areas, most ecological function still survives.

The findings reinforce a key conservation message: protecting wildlife is not only about saving species. It is about maintaining the living processes that allow ecosystems to function – processes that are already weakening across much of Africa.

Reference

Loft, T., Oliveras Menor, I., Stevens, N. et al. Energy flows reveal declining ecosystem functions by animals across Africa. Nature 649, 104–112 (2026).

Further reading

Safaris can be sustainable! We dig into why conservation is an important consideration when planning your African safari

Ebony and ivory: a tale of two collapses – New research reveals how Africa’s forest elephants sustain its darkest wood – and what happens when they vanish

Africa’s lions are disappearing. New research shows that lion populations across the continent have declined by 75% in just five decades. Read more here

A study on population growth, resource exploitation & climate change highlights the necessary steps for preventing loss of wild habitats & species in Africa. Read more on how Africa’s wildlife needs to be safeguarded into the 22nd century