- In 2018, five rangers had a rare encounter with a newborn Sumatran rhinoceros in the forests of Sumatra’s Leuser Ecosystem.
- Leuser is known as one of the last strongholds of the Sumatran rhino, one of the most endangered large mammals on Earth.
- Conservationists have called for beefing up security across the Leuser Ecosystem to allow the rhinos there to feel secure enough to continue breeding.
- The species is down to no more than 80 individuals in the wild, with forest fragmentation and a low birth rate driving it toward extinction.
JAKARTA — In 2018, five Indonesian forest rangers had an experience that would make them the envy of conservationists everywhere: they met a newborn Sumatran rhino in the wild.
“They were on a regular patrol, and then they heard a piercing voice,” Rudi Putra, a biologist and chairman of the Leuser Conservation Forum (FKL) Board of Trustees, told Mongabay over the phone recently. “They didn’t immediately recognize whose voice it was until they saw the calf.”
The Leuser Ecosystem in the northern part of Indonesia’s Sumatra Island is one of the last refuges of the critically endangered Sumatran rhinoceros (Dicerorhinus sumatrensis). The species’ global population is fewer than 80 individuals. Apart from perhaps as many as a dozen in Indonesian Borneo, all live on Sumatra. They all survive in small and isolated populations, with some considered to be doomed as they are not viable enough to survive in the long term.
The rhino population in Leuser is split up across four habitats. The area is touted by experts as the most promising site for wild Sumatran rhinos as it holds one of the largest numbers of the species. But of the four populations, Rudi said, only one has recorded natural births every year.
“In about a year, there’s two or three new calves in that place,” he said.
The five rangers saw one that day. The calf appeared to be alone, but the team knew the mother wasn’t too far away. The calf seemed to have been recently born, given that it hadn’t developed a sense of concern triggered by the foreign scent of humans. So it slowly and curiously approached the rangers. Seeing this, the group slowly stepped away and climbed up into the trees.
After a little while, the rangers made efforts to shoo the calf away. It finally decided to leave after seeming to realize that its mother wasn’t where the rangers were. The team also left the area immediately.
“There’s this wildlife behavior that when a baby animal has made contact with a human, the mother may not want to care for it anymore,” Rudi said. “That was their concern; so they immediately backed away and left.”
A Sumatran rhino population that still records natural births in the wild is crucial for the survival of the species. Many rhino experts say that natural breeding can only happen when the animals feel safe enough to mate, and therefore calls for full protection of all known habitats.
Widodo Ramono, executive director of the Indonesian Rhino Foundation (YABI), cites the Javan rhinoceros (Rhinoceros sondaica) as an example of the importance of a fully protected rhino habitat to its population.
A decade ago, the Javan rhino population was estimated at no more than 50 individuals. Efforts by the Indonesian government and organizations from around the world to beef up security across its last holdout, Ujung Kulon National Park, from encroachment and poaching have been in force for many years, and experts credit these measures for the stable increase in rhino numbers.
Poaching has not been reported in more than 20 years there, according to the International Rhino Foundation. Now, the Javan rhino population is increasing at a steady rate and recently authorities reported spotting two new calves, bringing the total number to 74 individuals.
“This [natural] breeding success like in Ujung Kulon can only happen when there’s full protection, and they [the rhinos] feel secure,” Widodo said during an online seminar for this year’s World Rhino Day on Sept. 22.
Rudi, who received the Goldman Environmental Prize in 2014 for his work helping shut down illegal oil palm plantations in the Leuser Ecosystem, agreed with Widodo’s assessment. While the Leuser rhinos live deep in the forest, encroachment by humans still occurs, albeit rarely and on the fringes of the forest. FKL reported that the average number of snare traps seized in the area by rangers fell to 0.012 per kilometer in 2019, from 0.14 per kilometer in 2016. The snares are typically set by villagers to catch bushmeat, but indiscriminately trap protected species too. A major reason for the decrease in the number of snare traps is the intensive patrolling by rangers inside Leuser, according to Rudi.
Wiratno, the director-general of conservation at Indonesia’s environment ministry, has pledged to enforce full protection of all Sumatran rhino habitats, and to reallocate conservation budgets to beef up security in these key ecosystems.
“There’s no other way than full protection,” Wiratno said during the World Rhino Day seminar. “There must be a quite large investment in funding or refocusing the funds within the park agencies like Leuser or Bukit Barisan.”
About half of the Leuser Ecosystem is currently protected, Rudi said. His organization has 150 rangers carrying out patrols in the rhino habitats across 400,000 hectares (988,000 acres) of forest in Aceh. It takes a team of five rangers 22 to 32 days to complete a single full patrol, on foot while carrying heavy equipment on their backs. Their task ranges from destroying animal traps to detaining hunters and illegal loggers.
“But that’s the risk,” Rudi said. “And that’s why 90 people still aren’t enough — we need more.” He added that dispatching a helicopter would help cut travel time for the patrolling team, and a drone to monitor and identify encroachers would help improve security for the rhino habitats.
Indonesia is also developing a Sumatran rhino sanctuary in Leuser as part of a nationwide emergency strategy issued in 2018 to save the species through captive breeding. In March, the East Aceh district administration allocated 7,302 hectares (18,044 acres) of land within the Leuser Ecosystem for the sanctuary. But nearly a fifth of that area falls within the concession of palm oil company PT Aloer Timur.
Rudi said authorities were still working on finalizing the papers for the sanctuary and the official approval to be issued by the environment ministry. He said he hoped construction would start in 2021. The priority is to rescue rhinos from so-called doomed populations — those that are so isolated that it’s unlikely the individual rhinos would ever mate in the wild, and with no signs of births in the wild — and relocate them to the sanctuary for breeding in captivity.
“When there isn’t any indication of breeding, it can be that there’s no male or female rhino, or because of disease,” Rudi said. “So we need to rescue them first and see the chances [for breeding]. It might be small, but there’s still a chance.”
But some rhino experts say in a recent scientific paper that the priority for the captive-breeding program at the sanctuary should be given to rhinos from populations that are “reproductively viable” to optimize their production.
Rudi acknowledged this approach is valid on those grounds, but said it risked disrupting the natural balance in the wild population. “What if we captured the only reproductively viable female rhino of that population when the others may not be as viable? Then we’re risking reducing the birth rate in that habitat,” he said.
And if a rescued rhino has reproductive problems, as tends to happen to females of the species that are isolated from males, then introducing an individual from a viable population should be done, Rudi said.
“For me, the best motivation is to keep them in their habitat. Because then we will also protect the wildlife, and that also means protecting their habitat,” he said. “The main focus must be on protecting them first, allocating all resources for protection, for stopping illegal activities and for forest restoration.”
Meeting a rhino calf in the wild “can only happen when intensive patrolling is taking place in the right areas so that the scale of intervention is very strong and measurable, and effective in helping increase the rhino population in those areas,” Rudi said.
A few days after that rare encounter in 2018, the team returned to the site and saw signs that the rhino calf had found its mother and the pair had left together.
“I think they are some of the luckiest people in the world,” Rudi said of his rangers.
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