THE ORANGUTAN POPULATION AND HABITAT VIABILITY ASSESSMENT (PHVA)  2016

The preparation of the Sumatran orangutan (Pongo abelii) and Bornean orangutan (Pongo pygmaeus) Population and Habitat Viability Analysis (PHVA) began in 2015 and concluded with a workshop in May 2016 in Bogor, West Java, Indonesia. 

​

This analysis result document was published in 2019 after several editing processes. The results of the 2016 Orangutan PHVA were then used as the primary reference in the development of the Orangutan Conservation Strategy and Action Plan (SRAK) 2019-2029, in place of 2007-2017.

 

This series of analytical activities were conducted in collaboration with the Directorate General of Conservation of Natural Resources and Ecosystems, The Ministry of Environment and Forestry of the Republic of Indonesia, the Indonesian Orangutan Conservation Forum (FORINA), the Orangutan Foundation-United Kingdom, the IUCN SSC Primate Specialist Group, the IUCN SSC Conservation Breeding Specialist Group, and institutions and orangutan conservation observers. 

​

According to the Orangutan PHVA, there are currently 71,820 individual orangutans remaining in Sumatra and Borneo (Kalimantan, Sabah, and Sarawak) in a habitat of 17,460,600 hectares. The populations are divided into 51 metapopulations, with only 38% expected to survive in the next 100-500 years.

 

Since the 2004 PHVA, more detailed studies on the population and distribution of the Sumatran orangutan (Pongo abelii) have been developed. The Sumatran orangutan population and distribution were originally predicted to be 6,667 individuals spread across a habitat area of 703,100 hectares at an altitude below 800 m asl; however, the population is now estimated to be 14,470 individuals spread across a habitat area of 2,155,692 hectares. 

​

The Sumatran orangutans are currently found in habitats up to 1,500 meters above sea level, spread across 10 metapopulations. Only two of the ten metapopulations are predicted to be sustainable (viable) in the next 100-500 years, and even then only at the Jantho release sites (South-East Aceh) and Bukit Tiga Puluh National Park (Jambi)

 

Another is in Sumatra, and another is in Borneo. There are currently an estimated 57,350 Bornean orangutans (Pongo pygmaeus) occupying a habitat area of 16,013,600 hectares spread across 42 habitat pockets. Around 18 individuals are predicted to be sustainable within the next 100-500 years. This condition updates the facts from ten years ago, which stated that the Bornean orangutan population is expected to be around 54,817 individuals in a habitat area of 8,195,000 hectares. 

​

Furthermore, there is a population of Bornean orangutans living in a landscape shared with Malaysia, namely a population of the subspecies Pongo pygmaeus pygmaeus in the metapopulations of Betung Kerihun National Park - Batang Ai-Lanjak Entimau, Klingkang Range National Park - North Sintang, and Bungoh National Park - Penrisen Protected Forest. To protect this population, Indonesia and Malaysia must collaborate on orangutan and habitat conservation.

According to Population Viability Analysis (PVA), the minimum population of Bornean orangutans that can survive in a habitat is 200 individuals, with a 1% chance of extinction in 100 years and a 10% chance of extinction in 500 years. Furthermore, it takes 500 individuals to preserve their quality and genetic variation. 
 

The declining orangutan population demonstrates that there are increasing threats to the survival of orangutans and their habitat, such as forest conversion. Furthermore, the high frequency of rescue and confiscation activities adds to the list of threats to orangutan survival. As a result, conservation areas must be protected, as must best management practices (BMPs) within the concession area that serves as orangutan habitat.

Final Report: Orangutan Population and Habitat Viability Assessment 2016 can be downloaded here

​

​

​