Javan Langur Release in Bromo Tengger Semeru National Park for Genetic Variation

  • Two Javan langurs were released in the East Semeru area. Based on studies, the East Semeru area is the right location to inject fresh blood into langur colonies
  • Fresh blood functions to repair genetic variations. Because a number of langur colonies in East Semeru are experiencing inbreeding or consanguineous marriages. The effect is that the langur offspring resulting from inbreeding are born deformed or sterile. Threatening extinction.
  • Javanese langur is one of three key animals in TNBTS. Key animals in TNBTS include the leopard (Panthera pardus) and the Javanese eagle (Nisaetus bartelsi).
  • Communities around the forest are asked to protect wild animals and their habitats. And stop hunting of animals in the forest.

The three of them, Head of Bromo Tengger Semeru National Park (TNBTS) Hendro Widjanarko, Javan Langur Center Manager, The Aspinall Foundation Indonesia Iwan Kurnaiwan and Head of the Lumajang Regency Environmental Service (DLH) Hartatik removed the rope tied to a tree. Together they removed the rope opening the Javan Langur (Trachypithecus auratus) cage in the TNBTS area in Senduro, Lumajang Regency, East Java, on Saturday (23/02/2024).

Two langurs take turns leaving the cage. Both are female. Lifa, about a year old and Tingting two years old. These two langurs with black and white fur immediately jumped up the tree and hung from the trees. For several hours, the two langurs were near the adaptation cage that was built three days before release. "Usually during the week we will be near the cage," said Iwan.

During the week, the two langurs will be monitored by volunteers to ensure their health condition and adaptation process in the wild. The monitoring process is carried out by professional staff who are often involved in the langur release process. Apart from that, it is also monitoring the possibility of joining other langur colonies in the forest area at the foot of Mount Semeru. Langurs aged one year to three years are ideal for release, "if less than a year old is too small. "My mentality is not good," said Iwan.

The two langurs came from the langur rehabilitation center at Javan Langur Center, Coban Talun, Batu City. According to Iwan, Lifa was confiscated by the East Java Regional Police and the East Java Natural Resources Conservation Center (BBKSDA) on July 8 2023 during a raid on a network of drugs and illegal goods. Dozens of langurs were also found and six were safe. The rest are sick and cannot be saved.

Meanwhile, Tingting was a voluntary handover from the Lumajang community on January 26 2023. Every rehabilitated animal underwent health screening at the JLC laboratory. Free from infectious diseases such as TB, Herpes, and SARS Cov-2.

If declared healthy, and no clinical symptoms of disease are found, they will undergo a quarantine phase for three weeks. Next, move on to the socialization pen to get to know each individual for six months to eight months. After adapting, the langurs are taught to recognize natural food. "Previously, they were usually given various human foods," he said.

Apart from that, they also learn to move and climb trees. Because langurs naturally spend time in trees. Once the langurs are skilled at climbing and eating natural food.

Adding Fresh Blood

The two langurs are part of the Lutung colony's supplement business or restaurant in the TNBTS area. After reviewing it with BBTNBTS officers, the East Semeru area is the right location to inject fresh blood into the Javan langur colony. The goal is to improve langur genetics.

Fresh blood, he said, is useful in the long term for genetic improvement and variation. Because a number of langur colonies in East Semeru are experiencing inbreeding or consanguineous marriages. The effect is that the langur offspring resulting from inbreeding are born deformed or sterile. So in the long term it will threaten extinction. "There is no choice, langurs mate between their own relatives," he said.

The real threat, he said, occurred in the Sempu Island Nature Reserve area, Sumbermanjing Wetan, Malang Regency. The area is isolated from the mainland, causing limited space for Javan langur colonies. Apart from that, each colony consists of a maximum of six to seven individuals. So inbreeding also occurs . So two months ago, two female Javanese langurs were also released on Sempu Island. "Physically, the langurs in Pulang Sempu are smaller than the average Javanese langur," he said.

Meanwhile, releasing langurs in the Kondakmerak protected forest, Sumbermanjing Wetan, Malang Regency is a reintroduction effort. Previously, the protected forest area had a colony of Javan langurs but this was reduced due to hunting and shrinking habitat. The aim of releasing individual Javan langurs is to increase the population.

Iwan explained that reduced habitat or forest destruction also threatens the decline in the Javan langur population. Apart from that, hunting also influences the rate of extinction of Javan langurs. Meanwhile, the Javan langur release location is quite safe from hunting. “In the last three years, massive hunting with nets has occurred in a number of protected forests. "The hunting process is long, but it can immediately catch all the individuals," he said.

Head of BBTNBTS Hendro Widjanarko explained that the total population of TNBTS Javan Langurs in the Ireng-ireng area is six groups. Each group consists of two to 10 animals. In Coba Trisula there were four groups consisting of six to 22 individuals, and in Gucialit two groups of seven and 13 individuals.

"Langurs are one of the three key animals in TNBTS," he said. Key animals include 12 leopards (Panthera pardus) , 36 Javanese eagles (Nisaetus bartelsi) . A number of officers patrol to prevent poaching and forest damage in the TNBTS area.

TNBTS officers' study shows that Javanese langurs' natural food is abundant in the area. The habitat, said Hendro, is maintained so that it becomes a safe home in the remaining natural forests in Java. Animals in the wild, he said, are also special interest tourist attractions.

BBTNBTS develops special interest tourism such as bird watching in the surrounding forest area in Darungan Village, Pronojiwo, Lumajang. This conservation-based special interest tourism is managed by the local community. So that the community is involved in protecting the area to carry out conservation activities.

“Bird watching with binoculars, there are towers and monitoring locations. "Birds are lured with food, whistles or bird recordings," he said.

Stop Hunting

Hendro also deployed officers to patrol and protect the area from poaching. Animal hunting, he said, could be controlled. A number of poachers were arrested and some were tried in local courts. “Last year there were several cases. It can be handled," he said.

Head of DLH Lumajang Hartatik asked residents around the forest in Lumajang to protect wild animals and their habitats. Protecting wildlife, he said, is important for posterity. So efforts are needed with early childhood education to help protect forests. Communities around the forest, said Suhartatik, were asked to protect and stop hunting animals in the forest.

“Practice shooting, enough for sport. Don't shoot animals in the forest. "Lumajang residents should not destroy, but maintain and protect the animal and biological diversity that we have," he said. Including Javan Langurs that are released into the wild, they are not the object of hunting.

Tidal trees (Lithocarpus sondaicus), Anggrung (Trema orientalis), and ficus are the main habitat of the Javan Langur. Meanwhile, natural food vegetation in nature includes leaves of kesek (Dodonaea viscosa), anggrung (Trema orientalis) , danglu (Engelhardia spicata) , genitri (Elaeocarpus sphaericus Schum) , kebek (Macaranga sp) , ficus, nyampoh (Litsea glutinosa), tide (Arthocarpus sp) , white breast (Haliaeetus leucogaster) , walisongo (Schefflera actinophylla) , and pandan (Pandanus tectorius).

According to Supriatna and Wahyono (2000) in the Guidebook. Indonesian Primate Field, the Javan langur has a body length from head to tip, adult males and females average 517 millimeters, and their tail length averages 742 millimeters. Average body weight is 6.3 kilograms. The fur color is silvery black. The ventral part is pale gray and the head has a crest. Javan Langur chicks are born orange-yellow and have no crest. Once mature it turns black and grey.

Langurs eat leaves, fruit and seeds. Javan langurs live in mangrove forests, lowland forests, highland forests, primary forests, secondary forests, plantations and plantation forests.

The International Union for Conservation of Nature and Natural Resources ( IUCN ) includes the Javan langur as vulnerable to extinction ( vulnerable / vu) and is listed in Appendix II or may not be traded in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) . Because the population of Javan langurs in nature continues to decline.

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