Pongo pygmaeus ssp. wurmbii
|Scientific Name:||Pongo pygmaeus ssp. wurmbii (Tiedemann, 1808)|
See Pongo pygmaeus
Pongo pygmaeus wurmbii is one of the three Bornean Orangutan subspecies currently recognized (Goossens et al. 2009). This taxon is found only in Indonesia, in the provinces of West, Central and East Kalimantan.
|Red List Category & Criteria:||Critically Endangered A4abcd ver 3.1|
|Assessor(s):||Ancrenaz, M., Gumal, M., Marshall, A.J., Meijaard, E., Wich , S.A. & Husson, S.|
|Reviewer(s):||Mittermeier, R.A. & Williamson, L.|
The estimated decline of the Southwest Bornean Orangutan subspecies has been over 50% during the past 40 years – less than two generations (Meijaard et al. 2011), and many small populations have already disappeared (Abram et al. 2015). The predicted rate of development in Indonesia will result in the destruction of more than half of the current orangutan range in the next 50 years or so, primarily because of forest loss due to conversion to agriculture and to fires (Wich et al. 2012). In most of the Southwest Bornean Orangutan's range, illegal hunting – for bushmeat, the pet trade and because of conflicts – remains a major factor in their decline (Davis et al. 2013, Abram et al. 2015). In sum, the subspecies will undergo > 86% decline in three generations (1950–2025) hence it qualifies for listing as Critically Endangered. See species-level assessment for further details (Pongo pygmaeus).
|Previously published Red List assessments:|
This subspecies is only found in Indonesia, in the provinces of West, Central and East Kalimantan. See species-level assessment for more information (Pongo pygmaeus).
|Range Map:||Click here to open the map viewer and explore range.|
The total number of Southwest Bornean Orangutans is still poorly known, but most of their range occurs outside protected areas. For a long time, several protected populations – Sebangau National Park and surrounding areas, home to the largest orangutan population in Borneo (Wich et al. 2008), Tanjung Puting National Park and Gunung Palung National Park – were perceived as being stable. However, despite their protected status, these populations are threatened by illegal logging, fire and conversion to agriculture, with the establishment of plantations and agroforests in and at the boundaries of these protected areas (Wich et al. 2012; Gaveau et al. 2013). Fires are a major threat: over 4,000 km2 of Sebangau peatland forest were burnt in 1997–1998, which resulted in an estimated loss of 8,000 orangutans in this population alone (Husson et al. 2015). Hunting, which is illegal, is also perceived as a real risk to sustaining the unprotected populations in the long term: all populations are expected to decline even further in the next 50 years (Abram et al. 2015).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
Bornean Orangutans are the largest arboreal mammals in the world, although they walk significant distances on the ground (Ancrenaz et al. 2014). Historically, Bornean Orangutans were most abundant in inundated and semi-inundated lowland Dipterocarp mosaic forests, where movement between different habitat types could buffer them against shortages in food availability in a particular habitat type. Their diet consists primarily of fruits, but also includes leaves, barks, flowers and insects (Russon et al. 2009).
Bornean Orangutans live a semi-solitary life and rarely aggregate in groups. Males are the dispersing sex: upon reaching sexual maturity (at 10–12 years old), they leave the area where they were born to establish large territories covering several hundred hectares. Females’ territories are smaller, with actual size depending on forest type and availability of food resources. Bornean Orangutans are very slow breeders and produce on average one offspring every 6–8 years, which explains their extreme sensitivity to hunting pressure. Females reach maturity at 10–15 years old; they generally give birth to a single infant after a gestation period of approximately 254 days (Kingsley 1981).
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||25|
|Movement patterns:||Not a Migrant|
|Use and Trade:||For information on use and trade, see under Threats.|
Major threats include:
The Bornean Orangutan is fully protected in Malaysia and Indonesia, and is listed on Appendix I of CITES. However, its forest habitat is not necessarily protected: about 20% of the current orangutan range in Sabah, and 80% in Kalimantan is not protected (Wich et al. 2012). Innovative mechanisms to ensure the long-term survival of Bornean Orangutans outside protected forests are urgently needed.
The future of Bornean Orangutans will very much depend on the long-term security of large, strictly-protected forests where illegal logging and hunting will be efficiently controlled and the orangutan populations large enough to cope with catastrophic events such as fires and disease outbreaks (Meijaard et al. 2011). These forests need to contain the ecological gradients that will provide the key resources to sustain orangutans through climate and other gradual environmental changes (Gregory et al. 2012). In the larger landscape, scientifically-based, regional land-use planning is needed to delineate zones of interaction around protected forests and their surroundings, encompassing hydrological, ecological and socio-economic interactions. Ideally, the core protected areas will remain connected to other areas of forest that could be used sustainably for (commercial) timber extraction. The design of such living landscapes must be approached across the whole landscape rather than at the site level.
Abram, N.K., Meijaard, E., Wells, J.A., Ancrenaz, M., Pellier, A.S., Runting, R.K., Gaveau, D.L.A., Wich, S., Nardiyono, Tiju, A., Nurcahyo, A. and Menkersen, K. 2015. Mapping perception of species’ threats and population trends to inform conservation efforts: the Bornean orangutan case study. Diversity and Distributions 21: 487–499.
Ancrenaz, M., Sollmann, R., Meijaard, E., Hearn, A.J., Ross, J., Samejima, H., Loken, B., Cheyne, S.M., Stark, D.J., Gardner, P.C., Goossens, B., Mohamed, A., Bohm, T., Matsuda, I., Nakabayasi, M., Lee, S.K., Bernard, H., Brodie, J., Wich, S., Fredriksson, G., Hanya, G., Harrison, M.E., Kanamori, T., Kretzschmar, P., Macdonald, D.W., Riger, P., Spehar, S., Ambu, L.N. and Wilting, A. 2014. Coming down the trees: is terrestrial activity in orangutans natural or disturbance-driven? Nature Scientific Reports 4(4024): 1–4.
Bruford, M.W., Ancrenaz, M., Chikhi, L., Lackman-Ancrenaz, I., Andau, M., Ambu, L. and Goossens, B. 2010. Projecting genetic diversity and population viability for the fragmented orangutan population in the Kinabatangan floodplain, Sabah, Malaysia. Endangered Species Research 12: 249–261.
Davis, J.T., Mengersen, K., Abram, N., Ancrenaz, M., Wells, J. and Meijaard, E. 2013. It’s not just conflict that motivates killing of orangutans. PLoS One 8: e75373.
Gaveau, D.L.A., Kshatriya, M., Sheil, D., Sloan, S., Molidena, E., Wijaya, A., Wich, S., Ancrenaz, M., Hansen, M., Broich, M., Guariguata, M.R., Pacheco, P., Potapov, P., Turubanova, S. and Meijaard, E. 2013. Reconciling forest conservation and logging in Indonesian Borneo. PLoS One 8: e69887.
Gaveau, D.L.A., Sloan, S., Molidena, E., Yaen, H., Sheil, D., Abram, N.K., Ancrenaz, M., Nasi, R., Quinones, M., Wielaard. N. and Meijaard, E. 2014. Four decades of forest persistence, clearance and logging on Borneo. PLoS One 9(7): e101654.
Goossens, B., Chikki, L., Jalil, F., James, S., Ancrenaz, M., Lackman-Ancrenaz, I. and Bruford, M.W. 2009. Taxonomy, geographic variation and population genetics of Bornean and Sumatran orangutans. In: S.A. Wich, S.S. Utami Atmoko, T. Mitra Setia and C.P. van Schaik (eds), Orangutans: Geographic Variation in Behavioral Ecology and Conservation, pp. 1–13. Oxford University Press, Oxford.
Gregory, S.D., Brook, B.W., Goossens, B., Ancrenaz, M., Alfred, R., Ambu, L.N. and Fordham, D.A. 2012. Long-term field data and climate-habitat models show that orangutan persistence depends on effective forest management and greenhouse gas mitigation. PLoS One 7(9): e43846.
Husson, S.J., Morrogh-Bernard, H., Santiano, Purwanto, A., Harsanto, F., McLardy, C. and D’Arcy, L. 2015. Long-term temporal trends in ape populations in four case studies: Bornean orangutans in the Sabangau peat-swamp forest. In: Arcus Foundation (ed.), State of the Apes 2015: Industrial Agriculture and Ape Conservation, pp. 200–207. Cambridge University Press, Cambridge, UK.
IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-1. Available at: www.iucnredlist.org. (Accessed: 30 June 2016).
Kingsley, S. 1981. The reproductive physiology and behaviour of captive orangutans (Pongo pygmaeus). University of London.
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|Citation:||Ancrenaz, M., Gumal, M., Marshall, A.J., Meijaard, E., Wich , S.A. & Husson, S. 2016. Pongo pygmaeus ssp. wurmbii. The IUCN Red List of Threatened Species 2016: e.T39782A17990568.Downloaded on 19 April 2018.|