- A new study finds that servals have surprisingly high densities in the Sasol Secunda petrochemical industrial complex in Mpumalanga, South Africa.
- The study authors concluded that this wildcat, native to sub-Saharan African wetlands and savannas, can adapt to anywhere it can find abundant prey, no matter how disturbed by human presence.
- Highlighting the benefits of industrial sites for wildlife must, however, be contextualized to ensure that preserving natural habitats remains the priority, according to another cat expert.
Why did the serval go to the petrochemical complex? For the refinery rodents, of course. These swift and slender wildcats that call the marshes and reedbeds of sub-Saharan Africa home have a penchant for rats and mice, though they’ll also feed on a mix of birds, insects and reptiles.
But for their preferred prey, they’ll leave the relative safety of their wetland homes and venture into human-modified landscapes. That’s the finding from a new study in Mammalia, which shows servals will adapt accordingly, persisting almost solely on rats and mice at one of the world’s biggest petrochemical complexes.
From specialization to adaptation
The serval (Leptailurus serval) may be a specialist carnivore, highly skilled at hunting small animals in wetlands and savannas, but that doesn’t mean it can’t adapt when push comes to shove.
“The anatomy, morphology, behavior and physiological adaptations of specialist carnivores allow them to find food efficiently and effectively,” said study lead author Fortune Ravhuanzwo, a conservation expert at South Africa’s University of Venda.
Ravhuanzwo’s team revealed that a serval population was able to not only survive, but thrive, in the Sasol Secunda petrochemical industrial complex in South Africa’s northeastern province of Mpumalanga.
By collecting 264 scat samples each year from 2013 to 2018, the scientists showed that even in this human-dominated landscape, the long-limbed cat remained a rodent specialist, with a preference for vlei rats (Otomys spp.) and multimammate mice (Mastomys spp.). Indeed, the serval population at the synthetic fuel plant breaks known density records: In 2018, scientists estimated it at 76-101 servals per 100 square kilometers (197-262 per 100 square miles).
Other species have also adapted to the presence of factories or open mines, such as the coyote (Canis latrans) and raccoon (Procyon lotor) in North America. Or consider the red fox (Vulpes vulpes) living in 114 cities worldwide — the champion carnivore of adaptation. Research has also found a few other African mammals doing the same.
“Emerging research in Africa shows a similar pattern where small carnivores thrive in urban centers,” reads the paper, citing the slender mongoose (Galerella sanguinea) and yellow mongoose (Cynictis penicillate), which now exploit the food sources of Pretoria and Johannesburg.
The new study adds the serval to this list.
The serval goes where the food is
Although it may have so far been associated with wetlands and savanna, the serval now appears to have a closer relationship with its prey — no matter how disturbed the landscape, the scientists write.
“The idea that industrialized sites could favor specialist carnivores like servals by providing certain beneficial features is intriguing,” said Zara McDonald, founder and president of California-based NGO Felidae Conservation Fund.
McDonald, who wasn’t involved in the study, said she believes this phenomenon comes with both potential short-term benefits and significant long-term risks for the serval. Given its lack of dietary flexibility, the medium-sized wildcat is vulnerable to prey scarcity, whether due to disease, agriculture, overhunting, urbanization or climate-related weather patterns, she said.
Contrary to generalist species, which have a broader range of prey species, specialist carnivores depend heavily on the critical resources and features that a human-altered habitat can provide, like human waste.
The study authors revealed that domestic waste attracts large populations of rodents, which in turn draws carnivores like servals. In addition, the absence of large competing or predating carnivores such as leopards (Panthera pardus) reduces food competition at these industrial sites. As Ravhuanzwo put it, they “tend to have a very large home range and are most likely not adapted to human-dominated landscapes.”
McDonald also agreed that fire-prevention infrastructure, for instance, may provide water for servals, while machinery and other urban structures shelter them from extreme weather by creating “unique micro-climates that could favor certain prey species.”
However, the risks linked to the proximity between servals and humans can’t be ignored, she said.
“Servals might be perceived as pests or threats to livestock and pets, leading to retaliatory killings or attempts to remove them from the area,” she said.
Exposure to toxic substances could also lead to long-term health issues for both servals and their prey, McDonald added. Habitat fragmentation could also isolate serval populations, making it harder to maintain healthy genetic diversity.
Finally, the reliance of servals on human-transformed habitats “could make them more vulnerable to changes in industrial activity such as site closures, waste management changes or shifts in land use that could suddenly deprive them of resources,” McDonald said. “Adapting to industrial environments might cause servals to lose some of their natural hunting and foraging behaviors. Over time, this could make them less able to survive in wild habitats.”
No substitute for natural habitats
Asked whether this study could inadvertently shift the focus away from preserving natural areas, McDonald said it was “crucial that such research is contextualized to avoid misunderstandings about conservation priorities.”
“Industrialized environments may provide short-term benefits, but they are not substitutes for natural ecosystems,” she said. “If industrial sites are portrayed as beneficial or acceptable alternatives, it may create complacency around the destruction of critical habitats. This could encourage development that compromises the very ecosystems species like servals evolved to thrive in.”
In response, Ravhuanzwo wrote that, “These areas have already been disturbed and cannot be reversed. However, by managing the surrounding environment, some species, such as the serval, can survive in these semi-natural/artificial environments,” adding that “this does not take away from the preservation of the serval’s natural habitats.”
He also noted several laws, like the National Environmental Management Act and the Mineral and Petroleum Resource Development Act, that regulate the continued construction of infrastructure and plants in South Africa.
Yet Sasol, as a state-owned oil and gas producer, is a major greenhouse gas emitter. According to its latest climate change report, the company generated more than 64,000 metric tons of CO2 equivalent in 2023, 84% of it from its Secunda plant. It even made the blacklist of the Carbon Majors database, which looks into the cumulative historical emissions of the world’s 122 largest producers of oil, gas, coal and cement. Carbon Major ranks Sasol at number 56 for emissions between 2016 and 2022.
So even as its facilities attract servals, its operations over time mean that this complex will never be a sanctuary for the species, McDonald said.
“If rodents like the African vlei rat … decline due to climate change impacts, servals would likely be forced to expand their range or migrate to new areas in search of food,” she said.
She added that servals’ ability to shift prey may only buffer them for a time. Ultimately, the scarcity of their preferred prey may push them to venture into other human-transformed landscapes, where the risk of conflict and exposure to habitat fragmentation is high.
“While studies like this one provide valuable insights into wildlife adaptability, they must emphasize that the observed benefits in industrial areas are temporary or limited, and should not replace the goal of habitat preservation,” she said. “Long-term survival and species health depend on functioning ecosystems.”
But with no prospect of industrial sites being reverted to natural ecosystems, and species like servals being increasingly drawn to them, industrial sites can still be important, Ravhuanzwo said.
“The study demonstrates the need to manage the environment surrounding already disturbed areas, like industrial sites,” he said. “Depending on how these areas are managed, the benefits could be long-lasting. A food source will always be available for the serval.”
Banner image: A serval photographed in the area by camera trap with the Sasol plant behind it in 2019. Image by Dan Loock.
Citations:
Ravhuanzwo, F., Loock, D. J., & Swanepoel, L. H. (2024). The importance of rodents to a specialist carnivore in an industrialized site. Mammalia. doi:10.1515/mammalia-2023-0079
Loock, D. J., Williams, S. T., Emslie, K. W., Matthews, W. S., & Swanepoel, L. H. (2018). High carnivore population density highlights the conservation value of industrialised sites. Scientific Reports, 8(1). doi:10.1038/s41598-018-34936-0
Mcdonald, R. I., Kareiva, P., & Forman, R. T. (2008). The implications of current and future urbanization for global protected areas and biodiversity conservation. Biological Conservation, 141(6), 1695-1703. doi:10.1016/j.biocon.2008.04.025