|Scientific Name:||Trachypithecus vetulus|
|Species Authority:||(Erxleben, 1777)|
|Infra-specific Taxa Assessed:|
|Taxonomic Notes:||An additional subspecies, T. v. harti, is also recognized by some experts, but is here included as a synonym of T. v. philbricki (Groves 2001).|
|Red List Category & Criteria:||Endangered A2cd+3cd+4cd ver 3.1|
|Assessor(s):||Dittus, W., Molur, S. & Nekaris, A.|
|Reviewer(s):||Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)|
This species is listed as Endangered as it is believed to have undergone a decline of more than 50% over the last 3 generations (36 years, given a generation length of 12 years) due to a combination of habitat loss and hunting and is predicted to decline at the same rate over the next three generations.
|Previously published Red List assessments:|
|Range Description:||This species is endemic to Sri Lanka (Corbet and Hill 1992). |
Trachypithecus vetulus vetulus
This subspecies is found in the rainforests of southern Sri Lanka from south of the Kalu Ganga to about Rama (Groves 2001). It ranges in elevation up to 1,000 m (Molur et al. 2003).
Trachypithecus vetulus nestor
This subspecies is found in western Sri Lanka, from the north of the Kalu Ganga as far north as the rainforest limit (Groves 2001). It ranges in elevation up to 1,000 m (Molur et al. 2003).
Trachypithecus vetulus philbricki
This subspecies is found in the north and east of Sri Lanka in the dry zone, up to 800 m in East Matale and Madukelle Hills (Groves 2001; Molur et al. 2003; W. Dittus et al. pers. comm.).
Trachypithecus vetulus monticola
This subspecies is found in the mountains of central Sri Lanka (Groves 2001). Molur et al. (2003) and W. Dittus (pers. comm.) report that it is found from 1,000 to 2,200 m in elevation.
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Population counts are required, as very little is known about the species (A. Nekaris pers. comm.). However, the overall picture is one of serious decline.|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||According to Molur et al. (2003), Trachypithecus vetulus vetulus is found in “lowland and midland tropical rainforest and modified areas with adequate canopy cover. Where its natural habitat has been destroyed, groups may refuge in home gardens and plantations, but these commensal habitats, too, are threatened and offer no long-term survival prospects for the taxon”. Forest fragments may result in artificially dense populations (i.e. depending on the fragments, population size may seem higher). The range is less than 5,000 km2 (A. Nekaris pers. comm.).|
According to Molur et al. (2003), Trachypithecus vetulus nestor is found in “lowland tropical rainforest, while refugee populations presently inhabit semi-urban and rural home gardens, rubber plantations and areas with adequate canopy cover where these have replaced the original natural forest”; Trachypithecus vetulus monticola is found in “montane tropical rainforest” and Trachypithecus vetulus philbricki is found in “dry evergreen forests, tropical monsoon and deciduous dry forest, confined to moister areas of dry zone with tall closed forest canopy near permanent sources of water”.
Molur et al. (2003) summarize the threats for the four subspecies:
Trachypithecus vetulus vetulus: selective logging (wet zone forests in 1970s), human settlement, hunting, trade, habitat loss, encroachment for agriculture, plantation, and human habitation. Ill-conceived government-organized translocation schemes of langur groups, coming into conflict with man, pose a threat to taxon survival and overall biodiversity. According to government data, during one 42-year period (1956-1993), the country has lost 50% of its forest cover, and more than 50% if the subsequent 10 years (1994-2003) is included. There is a 1:1 relationship between loss of critical habitat and population number. There is also a local trade for meat for food and pelage for making drums at village level for subsistence.
Trachypithecus vetulus monticola: deforestation, fragmentation and habitat loss (crop plantation, development, human settlement) and hunting for subsistence or small scale cash. According to government data, during one 42-year period (1956-1993), the country has lost 50% of its forest cover, and more than 50% if the subsequent 10 years (1994-2003) is included. In addition, 80% of hill country forests were lost to tea plantations in the 19th century. There is a close relationship between loss of critical habitat and population number. There exists a local and domestic trade for meat and skin. Locally pocketed and isolated groups are prone to extinction due to village-level subsistence exploitation.
Trachypithecus vetulus nestor: crop plantations, development (infrastructure, industry), human settlement, deforestation, fragmentation, illegal trade for food, pylon collision, and habitat loss. There is also a local trade at village level for meat, but it is not significant.
Trachypithecus vetulus philbricki: shifting agriculture, deforestation, human settlement, development, hunting for food, habitat loss, and occasional cyclones in far northeastern areas of range. According to government data, during one 42-year period (1956-1993), the country has lost 50% of its forest cover, and more than 50% if the subsequent 10 years (1994-2003) is included. The Mahaweli Development Scheme after 1978 had further reduced available habitat for this taxon. There is a close relationship between loss of critical habitat and population numbers. There exists a local trade for meat and skin. The animals are hunted mainly for subsistence living and trade at local village level. Skins in some areas are used to make drums. This may lead to extinction of subpopulations.
This species is listed on CITES Appendix II. The following conservation management actions have been recommended for the subspecies (Molur et al. 2003):
Trachypithecus vetulus monticola: habitat management, limiting factor management, monitoring, and implementation of extant conservation laws; and the following areas in need of research: surveying, genetics, taxonomy, ecology, behavior, life history, epidemiology, and limiting factors.
Trachypithecus vetulus nestor: habitat management, public education, limiting factor management, work in local communities, and a coordinated Species Management Program; and the following areas in need of research: genetics, taxonomy, life history, behavior, surveying, limiting factor research, epidemiology, and studies to identify viable method of conserving the subspecies.
Trachypithecus vetulus philbricki: habitat management, monitoring, limiting factor management, Population and Habitat Viability Assessment, and implementation of extant laws a priority; and the following areas in need of research: taxonomy, life history, surveying, limiting factor research, epidemiology, trade, zoogeography, population genetics, ecology, and behavior.
Trachypithecus vetulus vetulus: habitat management, public education, government education, implementation of extant conservation laws; and the following areas in need of research: genetics, taxonomy, life history, surveying, ecology and behavioral studies. This taxon is found in many protected areas, but most of the areas have introduced pine species, with very little protection, and much of the remaining forests are rubber or other cash crop plantations. The protected areas are not the size determined, and do not have protection (A. Nekaris pers. comm.). Some conservation has been undertaken for this taxon; systematic conservation education programs were launched in 2001 and have increased awareness of this taxon (A. Nekaris pers. comm.).
Corbet, G.B. and Hill, J.E. 1992. Mammals of the Indo-Malayan Region: a Systematic Review. Oxford University Press, Oxford, UK.
Groves, C.P. 2001. Primate Taxonomy. Smithsonian Institution Press, Washington, DC, USA.
Molur, S., Brandon-Jones, D., Dittus, W., Eudey, A., Kumar, A., Singh, M., Feeroz, M. M., Chalise, M., Priya, P. and Walker, S. 2003. Status of South Asian Primates: Conservation Assessment and Managment Plan Report. Workshop Report, 2003. Zoo Outreach Organization/CBSG-South Asia, Coimbatore, India.
Rudran, R. 1973. Adult male replacement in one-male troops of purple-faced langurs (Presbytis senex senex) and its effect on population structure. Folia Primatologica 19(2): 166–192.
Rudran, R. 1973. The reproductive cycles of two subspecies of purple-faced langurs (Presbytis senex) with relation to environmental factors. Folia Primatologica 19(1): 41–60.
|Citation:||Dittus, W., Molur, S. & Nekaris, A. 2008. Trachypithecus vetulus. The IUCN Red List of Threatened Species 2008: e.T22042A9350371.Downloaded on 27 August 2016.|