Finding a lost turtle by tapping into people’s wisdom

In a first, scientists used local ecological knowledge to spot nests and hatchlings of the Cantor's giant softshell turtle, thought to be locally extinct, writes Spoorthy Raman

In the monsoon months of 2019, turtle researcher Ayushi Jain and her team visited a few villages on the banks of the Chandragiri River in Kasargod, Kerala, to check how the Cantor’s giant softshell turtle was doing. Between 1970 and then, scientists had recorded only 15 sightings of this elusive turtle, and recent surveys had spotted none. Jain and her team set out to confirm if the critically endangered turtle had gone extinct in the region. 

“Our study focused on gathering local ecological knowledge from the communities to understand its current status in Kerala,” says Jain, a PhD researcher at the University of Miami, USA. The study involved an international team of researchers and was published in the journal Oryx.

Local ecological knowledge is the knowledge people have about their environment and the biodiversity living in it. “This is often passed on through generations and could be related to the cosmovision of some communities or groups,” says study coauthor Francoise Cabada-Blanco at the University of Portsmouth, UK.  

“Local ecological knowledge can play a crucial role in the study of rare and elusive turtle species, especially those like the Cantor’s giant softshell turtle,” says freshwater turtle researcher Ramya Roopa Sengottuvel, who was also not involved in the study, “These turtles are not known to bask on land, making them difficult to spot during traditional surveys. Therefore, it is critical to leverage various approaches, [including] local ecological knowledge, literature records, molecular techniques and traditional surveys in studying the ecology and behaviour of these animals.”

Cantor’s giant softshell turtle (Pelochelys cantorii) is a large freshwater turtle found in South and Southeast Asian rivers. It can grow over a meter in length and weigh a whopping 100 kilograms. It spends most of its time buried in the riverbeds. As a scavenger, it helps maintain water quality. However, in recent decades, the species has vanished from much of its range due to habitat destruction, poaching for its meat, or being caught as bycatch.

The researchers interviewed 150 villagers living on the banks of Chandragiri River. They quizzed them on whether they had seen the turtle, called paala poovam in Malayalam, in the region anytime in the last ten years. They also asked whether the villagers hunted them for meat and if they knew anything about their nests. “The team was lucky, and people got engaged and started reporting sightings and accidentally caught individuals,” says Cabada-Blanco, “What started as local ecological knowledge progressed to the start of a citizen’s science [project].”

The villagers reported sighting the turtles mainly during the afternoons in the dry season (March-May) when the rivers run almost dry—confirming the Cantor’s giant softshell turtle wasn’t extinct. In addition, they also informed the turtles nested on riverbanks. Each nest was 30-40cm deep, with around 100 eggs laid in a spiral fashion—providing the first evidence of a breeding population. 

“In India, the nesting ecology of the species was completely unknown,” says Jain, adding that information about the turtle’s nesting ecology and critical habitats help with conservation. “Since the threats to the species are known, we can strategically start addressing them while preserving the interests of local communities.”

Tapping on local knowledge

When scientists try to understand an ecosystem, they look at every species and study them in detail. In tropical ecosystems with thousands of species, cataloguing and studying each species in depth is tedious and often impossible, creating scientific gaps. “In that context, it is very useful to speak to local people who have much more regular interactions with species,” says marine conservationist Divya Karnad, who was not involved in the study. “Integrating local ecological knowledge helps fill these gaps because it approaches the same topic differently.” 

In Kasargod, Jain has tapped into the villagers’ knowledge to set up a network of informants who share information about their sightings, bycatch and nests. Between 2019 and 2022, informants have reported nine direct sightings of the turtle, seven bycatches and six nests. The researchers have also conducted training and awareness workshops for fishermen to train them to handle, report, and rescue individual turtles caught in their fishing gear until the forest department arrives. 

“We have started an in-situ nest protection programme where the communities monitor the nests until they hatch,” says Jain, adding that the informants’ network can aid in long-term monitoring of the species. “Going forward, I will continue working with the communities to find sustainable solutions to addressing the threats from dams.” 

In an increasingly urbanising world, people’s interest in and interactions with nature have dwindled, threatening generations of ecological knowledge they once had.

“There is a misconception that [local ecological] knowledge is only present among certain types of forest dwellers and rural people, but anyone can have it,” says Karnad. “You need to have interactions, not through a camera lens.”