The Javan rhinoceros Rhinoceros sondaicus is critically endangered in a small area of Ujung Kulon National Park in Indonesia, where the population numbers about 70 individuals. Threats equivalent to tsunamis, diseases and poachers increase the chance of their survival. Reports by the NGO Auriga Nusantara about mismanagement of the park have raised concerns, including claims that rhinos must be dead but are still officially recognized as alive.
A recent article in Gazella magazine suggests latest measures, detailing the concept of cutting down large trees in national parks to expand rhino feeding areas. The study also highlighted concerns about inbreeding within the population, resulting in proposals to ascertain captive breeding centers as a safety measure.
Francesco Nardelli, writer of the study from the Asian Rhinoceros Specialist Group at IUCN, said genetic testing of Javan rhinos showed low genetic diversity within the population. This is commonly related to inbreeding depression, increased disease risk, and decreased physical fitness.
According to his findings, the federal government’s Endangered Javan Rhino Management Program, with detailed plans for 2023-2029, revealed that 13 Javan rhinos had “congenital defects”, more than likely attributable to a long time of breeding in small groups.
Food or cutting down trees?
Another problem is the gender imbalance within the Javan rhino population, with fewer adult females than males. According to Francesco Nardelli, there are only a few dozen adult females able to breeding, and although they proceed to present birth, the method is probably not fast enough to extend or maintain the population, which has now bottomed out at around 70 individuals.
To solve the genetic problem, Jan Robovský, a biologist on the University of South Bohemia within the Czech Republic, suggests that the most effective solution is to create a bigger population. However, concerns have been raised that the present population may already be at its lowest limit, around 70 individuals, and that the present habitat may not give you the chance to support the rise in numbers.
Robovský compared the Javan rhino to the Indian rhino, a bigger species of rhino in the identical genus. While the Indian rhinoceros population recovered quickly after poaching stopped, the Javan rhinoceros population has not experienced the same recovery. Whether that is because of constant poaching within the park or limited space and food resources stays an issue that is still to be answered.
Nardelli and Robovský advisable that one technique to address the food shortage for Javan rhinos could be to chop down a few of the large trees in Ujung Kulon National Park. Nardelli emphasized that Javan rhinos, as foragers, use leaves as their most important food source. Creating open space is anticipated to encourage the expansion of forage plants, provide a more abundant food source and make it easier for rhinos to access food, especially given the limited habitat within the park.
Although park management has tried to chop down fast-growing palm trees to make room for plants favored by rhinos, Nardelli and Robovský expressed the necessity to proceed cutting down trees in areas which have not yet been overgrown with palm trees.
The government’s Javan Rhinoceros Management Plan 2023–2029 states that “a brand new management system will likely be designed to optimize the carrying capability of the Javan Rhinoceros habitat”, but provides no further details.
Nina Fascione, head of the International Rhino Foundation (IRF), which is working with the Indonesian government to guard rhinos in Ujung Kulon, said additional improvements in habitat management would make a major contribution, but asked researchers to elucidate the proposals in additional detail.
Robovský also suggested removing some banteng from the national park to scale back competition with Javan rhinos for food. Although the banteng is on the endangered species list, Fascione emphasized that our current focus is on protecting the wild, naturally breeding rhino population.
Breeding in captivity
Speaking of captive breeding, Nardelli and Robovský also advisable establishing a captive breeding center for Javan rhinos, following the model successfully used for Sumatran rhinos (Dicerorhinus sumatrensis).
Although captive breeding is included in the federal government’s management plan, experts hope it’ll not be implemented any time soon. According to Fascione, captive breeding could develop into a key tool in efforts to guard Javan rhinos. He added that a captive species conservation program that features careful gene management and rapid population growth could also be the most effective solutions to this challenge.
Currently, the Indonesian government is developing a brand new complex throughout the national park, often called the Javan Rhinoceros Research and Conservation Area (JRSCA). The government’s plan is that after the completion of this project it’ll consider “the translocation of chosen people.
Nardelli explained that introducing some rhinos to a semi-wild captive breeding program could contribute to scientific understanding that will improve the survival of the species. In a controlled environment, researchers can monitor reproductive behavior, conduct research on reproductive physiology, and collect helpful data to support conservation efforts in captivity and natural habitats.
Although Sumatran rhinos are more vulnerable and their population may number fewer than 50 individuals, years of research in captivity provide more in-depth knowledge. In turn, the Javan rhinoceros has not been recorded in captivity for over a century, making it one in every of the least known rhinoceros species.
For example, the article highlighted ongoing confusion over a Javan rhinoceros specimen in Italy that had previously been misidentified as a bigger one-horned rhinoceros. This error is taken into account common and, in line with the authors, requires a re-evaluation of all specimens in museums and collections world wide.
Addressing the lack of expertise in regards to the reproductive behavior of Javan rhinos, Nardelli stressed the importance of such information for developing effective conservation strategies, which may only be assessed through captive breeding programs outside their habitat.
Conservationists have advocated for efforts to ascertain a second Javan rhino site within the wild in Indonesia, with the goal of expanding the population beyond Ujung Kulon. However, the Indonesian government has not yet selected a location, and plans to go looking for the “other area” were placed on hold in 2019 with no indication that they’ll resume.
Source: Mongabay
