Pangolins, the world’s most trafficked mammals, hit the headlines more often for the illegal trade in their scales and meat than for their cherished role in their environment. As insectivores, these scaly anteaters feast on termites and ants and keep their numbers in check. By digging burrows with their powerful claws, they turn soil and cycle nutrients. Their abandoned burrows become home for many reptiles, birds and other small mammals.
A recent study adds new evidence to the pangolin’s role in the environment as ecosystem engineers. The study, published in the journal Global Ecology and Conservation, finds that burrows dug up by Chinese pangolins (Manis pentadactyla) encourage the growth of plants and provide shelter to surviving animals in forests devastated by fires. It presents the first qualitative evidence for pangolins’ role in accelerating the recovery of degraded ecosystems, such as burned forests.
“For a very long time, people have speculated that pangolins play a critical role in the ecosystem,” says conservation ecologist Matthew Shirley from Florida International University and co-chair of the Pangolin Specialist Group at the IUCN, the global wildlife conservation authority, who wasn’t involved in the study. But qualitative evidence for their role as ecosystem engineers has been missing because collecting such data “is a really challenging thing,” he says.
Since all eight known pangolin species in the world are on the brink of extinction due to poaching for their scales and meat, scientists barely get a chance to study their ecological role.
“So that’s why this study is actually really interesting,” Shirley says.
The researchers behind the study lucked out when they visited forests in the Heping and Chao’an regions of Guangdong province in southern China, which were burned by fires in 2021 and 2022. “By chance, we observed that pangolins began excavating burrows in forests that had been subjected to fires just one month after the event,” lead author Song Sun from the Guangdong Academy of Forestry told Mongabay by email. That sight “captured our interest” in studying their ecological role in degraded forests, Sun said, and they began collecting data.
Chinese pangolins are a critically endangered species native to southern China and parts of mainland Southeast Asia and South Asia. During the winter, they dig deep underground burrows, sometimes going down 2.4 meters (8 feet), and pseudo-hibernate in them, where their metabolism and body temperature drop slightly, but they don’t fall into a deep sleep. Chinese pangolins are the only pangolin species known to overwinter. Each year, an individual can dig anywhere between 50 and 100 burrows.
The researchers selected 54 sites with pangolin burrows within burned forests in Heping and Chao’an, and a similar number of control sites without burrows for comparison. They installed cameras at the burrow entrances to monitor and catalog which animal species used the burrows, and recorded the species of plants at each site in 2021 and 2022.
Their analysis showed that sites with pangolin burrows attracted more plant and animal species than sites without burrows. While the researchers recorded 58 plant species and nearly 3,000 individual plants at areas with burrows, the control sites exhibited only 47 plant species and 2,165 individuals. Animals were also plentiful near burrow sites: 35 species and 1,041 individuals were recorded, including 24 bird, 10 mammal and one reptile species. By comparison, only 23 animal species and 427 individuals were seen at the control sites.
Birds such as spotted doves (Spilopelia chinensis), Daurian redstarts (Phoenicurus auroreus) and Tristram’s buntings (Emberiza tristrami) frequented pangolin burrows the most. Other visitors included leopard cats (Prionailurus bengalensis) and rodents such as rats and gerbils. Black maidenhair fern (Adiantum capillus-veneris) and Asian raspberry (Rubus phoenicolasius) were prominent plants at the burrow sites.
The researchers attribute the increased biodiversity at the burrow sites to the unique microhabitats that burrowing creates. When pangolins dig up topsoil, they make nutrients more accessible to plants. Mound soil has higher moisture and lower sand content, which helps seeds germinate and rhizomes grow underground.
“Pangolins’ burrowing activities significantly promote the recovery of biodiversity in burn sites,” Sun said, adding that this effect was pronounced just after the fires. “The presence of various plant species in burrow microhabitats is significantly and positively correlated with the occurrence of burrow commensal birds, indicating that frequent use of burrows by birds benefits the dispersal of plant seeds into burn sites.”
Inside the burrows, the consistent temperature and humidity attract shade-loving plants. Abandoned pangolin burrows provide thermal refuge to cold-blooded animals that survived the forest fires. Birds also use burrows as dust baths, and small mammals use them as a foraging and hunting ground.
“Our research shows that pangolins and other burrowing animals are likely to play the ecological role of umbrella species in the ecosystem,” Sun said. “Once pangolins go extinct, it is very likely to have adverse effects on other species and communities that rely on pangolin burrows.”
In a world where forest fires are getting worse due to climate change, this research suggests pangolins could help in the regeneration of landscapes if given a chance. In China, where all native pangolins are now protected species and the country has established a pangolin conservation research center, rewilding pangolins could help rejuvenate forests damaged by fires, researchers say.
“I hope that the results of the study inspire other researchers to get in the game and start to better understand the really significant ecological role that pangolins play,” Shirley said, adding that if we let pangolins thrive, they can take over the role of ecological restoration. “Nature can handle its own as long as we get out of the way a little bit.”
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