Wild release signals return of giant forest tortoises to Bangladesh hills

Researchers and villagers last month released 10 captive-bred Asian giant tortoises into Bangladesh’s Chattogram Hill Tracts to boost numbers of the threatened species in the wild, once thought to be extinct in the country.

Asian giant tortoises
The ten juvenile, captive-bred Asian giant tortoises are fitted with radio transmitters at the Turtle Conservation Center in Bhawal National Park prior to their release. Image: Kowshikur Rahman / CCA

Bangladesh’s population of one of the world’s largest tortoise species received a boost last month when researchers and villagers released 10 captive-bred juveniles into the evergreen forests of the Chattogram Hill Tracts. This initiative, in the rugged mountain range in the extreme southeast of the country bordering Myanmar and India, was the first rewilding of the Asian giant tortoise in the country.

The species, Manouria emys, is critically endangered due to heavy hunting pressure and habitat destruction throughout its range across South and Southeast Asia. Tipping the scales at 35 kilograms (77 pounds), it’s the fourth-largest tortoise in the world and highly prized by subsistence hunters for its meat. Scientists had thought the species was extinct in Bangladesh until 2011, when new hope was triggered by the discovery of a shell in a remote corner of the Chattogram Hills.

“This confirmed that they still occur in that tiny pocket,” Shahriar Caesar Rahman, co-founder and CEO of the Creative Conservation Alliance (CCA), a Bangladesh-based nonprofit, told Mongabay. Without any action, he said, the species would likely be completely lost within the next decade. “What we needed to do was to increase their population size in captivity.”

Over the next few years, local hunters relinquished several of the rare tortoises to conservationists, and in 2017 CCA established a captive-breeding center to help secure the reptile’s future in collaboration with local communities, the Bangladesh Forest Department, and U.S.-based nonprofit Turtle Survival Alliance.

Today, the Turtle Conservation Center (TCC) in Bhawal National Park houses Bangladesh’s first conservation breeding colonies of not just Asian giant tortoises, but also critically endangered Arakan forest turtles (Heosemys depressa) and elongated tortoises (Indotestudo elongata), and endangered keeled box turtles (Cuora mouhotii).

Slow but steady progress

The 10 newly released Asian giant tortoises hatched in 2019 and are the offspring of parents rescued from slaughter. At the age of 2.5 years, they are large enough to evade natural predators, but they will not begin breeding until they are 15-20 years old.

As with so much in tortoise lives, Rahman said he anticipates slow but steady progress in recovering numbers in the wild. Although it took several years to begin breeding the tortoises, they are now breeding with regularity. Still, he reports that sudden cold snaps of weather during the monsoon season can catch them off guard leading to the loss of eggs and hatchlings.

“We are still trying to figure out how to increase the breeding success,” Rahman said, adding he hopes they can produce 100-200 hatchlings per year to keep boosting wild numbers. It’s a realistic target, he said, since high losses during egg incubation and hatchling stages are somewhat offset by the species’ extraordinary fecundity — female Asian giant tortoises typically lay up to 50 eggs in a clutch.

The release is a big initial step toward rewilding the species not just in Bangladesh, but also in Myanmar and India, where captive breeding “assurance colonies” for the species have also been established and are anticipating their first releases into the wild, said Rick Hudson, president of the Turtle Survival Alliance.

“It’s been really rewarding to take animals that were kind of doomed and be able to put them into a conservation programme,” Hudson said. “They’re heavily hunted … it’s only in remote tracts of undisturbed forest where they are still found. So it was important to develop breeding colonies for this species throughout their range to give us options for restoring them to some of these habitats.”

Besides caring for hatchlings, providing an amenable breeding environment is a major challenge for this species, according to Hudson. The “perfect physical condition” of the 10 new releases is testimony to how well the tortoises have been cared for at the TCC, he said.

“This is a difficult species [to keep] in captivity, because unlike species of tortoise that make a nest, lay their eggs, and that’s it, this species is very primitive,” Hudson said. “They build a nest much like a crocodilian. So you have to give them a lot of organic material and leaves and they’ll spend days mounding up a huge nest — I’ve seen these nests at more than 3 feet [1 meter] tall.”

Survival in the wild

Besides tortoises and turtles, the Chattogram Hill Tracts are one of Bangladesh’s last strongholds for many other animals. Recent surveys have found evidence of tigers (Panthera tigris), leopards (Panthera pardus), marbled cats (Pardofelis marmorata), sambar deer (Rusa unicolor), gaur (Bos gaurus), dhole (Cuon alpinus), several species of hornbill, and rare primates like the western hoolock gibbon (Hoolock hoolock) and Phayre’s leaf monkey (Trachypithecus phayrei).

But the region is opening up to settlement and development, placing the rainforest and its wildlife under increasing pressure from poaching, logging and agricultural expansion. Between 2001 and 2014, the region lost more than 30 per cent of its forest cover.

Recognising the precarious fate of the region’s biodiversity, Rahman and the CCA have forged strong relationships with local people and communities to ensure wildlife protection is at the forefront of decision-making.

Encouraging action at the local community level is a crucial aspect of the Asian giant tortoise rewilding project, according to Rahman. “Breeding is probably the easiest part of the conservation of this species,” he said. “The ultimate challenge is how to engage the communities in the long run so that they don’t hunt them.”

To reduce hunting of turtles in the region, the CCA has set up conservation agreements with several hill tribe villages that entail moratoriums on logging and hunting in demarcated areas. In return, the conservation organisation supports schools, provides livelihood programmes for local artisans, and trains former hunters as “parabiologists,” or citizen scientists, who collect data and monitor species to help protect local wildlife.

The Asian giant tortoises were released into a 200-hectare (490-acre) patch of community forest that is managed under such an agreement and further governed by a village conservation committee operating under the supervision of the village chief. Each released tortoise was fitted with a GPS tracker so that local parabiologists can monitor their activity and ensure they don’t stray into forest areas where hunting pressure and logging are unmanaged.

Rahman had just returned from a monitoring trip when Mongabay interviewed him for this story. So what were the tortoises doing with their newfound freedom? True to their nature, they hadn’t roamed far. They were mainly “burrowing into the leaf litter and resting in tree crevices,” Rahman said, “their activity pattern is pretty relaxed at this time of year.”

While tortoise conservation is a slow burn, the captive-breeding center has helped turtles and tortoises become flagship species for forest protection by local communities.

“We have to be realistic in the Bangladeshi context,” Rahman said. “It is a country with one of the highest human densities, about 1,200 people per square kilometer, which creates huge pressure on the remaining habitat. Conserving larger species, which [would require] a larger area, is very difficult. So using these medium-sized species is a realistic approach.”

Besides inspiring communities to protect their forests, reestablishing healthy wild populations of turtles and tortoises in the Chattogram landscape will also restore the key seed dispersal services they provide, in turn enhancing the area’s potential for natural ecosystem regeneration.

And this first release is just the beginning. Over the coming decades, the team hopes to replicate its turtle rewilding approach in many other areas and communities in the Chattogram Hill Tracts.

“Our goal is to restore the landscape using turtle rewilding as a tool to engage the community,” Rahman said. “When you release an animal, people are engaged and the forest can be protected to help other species as well.”

This story was published with permission from Mongabay.com.

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