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Researchers predict decline in proboscis monkey population

20 February 2012

Cardiff University researchers and conservationists in Sabah have shown that proboscis monkey populations throughout Borneo may experience population decline if nothing is done to stop their habitat degradation.

The study, carried out by Cardiff University & the Danau Girang Field Centre, the Sabah Wildlife Department (SWD), and Oxford Brookes University with researchers from Indonesia is published in the scientific journal Endangered Species Research.

Proboscis monkeys are mainly confined to peat and freshwater swamp forests, mangrove forests, and lowland dipterocarp (riverine) forests, habitats which are the most threatened in Borneo because of logging and conversion of land for agriculture.

Proboscis monkeys are one of the most distinctive looking primates on the planet, having the longest noses of all primates. In Sabah, only 15% of proboscis monkey groups are in fully protected areas. The remaining populations are divided between those residing outside of the reserve network completely or those within partially protected forest reserves, where different levels of extraction are permitted.

The study looked at different scenarios to determine their influence on the declining population trends of three populations, two in Kalimantan and one in Sabah. The Sabah population was the Lower Kinabatangan Wildlife Sanctuary. The conservation strategies evaluated in the study were: (1) eliminating hunting; (2) eliminating fires; (3) eliminating deforestation; (4) reducing deforestation; (5) implementing reforestation programs and (6) reconnecting sub-populations.

The study used current population surveys and predicted a decrease of about 1,000 monkeys within the next 50 years in the Lower Kinabatangan Wildlife Sanctuary. It was found the scenario with the greatest improvement on each population was reconnecting the population through forest corridors in the Lower Kinabatangan Wildlife Sanctuary.

Danica Stark, PhD student Cardiff School of Biosciences & lead paper author said: "Recent surveys carried out by the non-governmental organization HUTAN and Danau Girang Field Centre showed a similar pattern of population decrease in the Lower Kinabatangan Wildlife Sanctuary.

"Whilst the Lower Kinabatangan Wildlife Sanctuary population is not predicted to become extinct within the next 50 years (probably because of its current high population size – of about 3,000 individuals), it is extremely likely that if nothing is done to stop deforestation and the increase of habitat loss and fragmentation, and to reconnect forest fragments along the main river and its tributaries, the proboscis monkey population will become in great danger of extinction."

Dr Laurentius Ambu, Director of the Sabah Wildlife Department said: "There has been a strong conservation presence in the Lower Kinabatangan Wildlife Sanctuary in the past decade. However, there are too many narrow strips of forest along the Kinabatangan which are not sufficient and can result in the death of monkeys and their feeding trees due to over-exploitation. We need to identify the severity of riverine forest which have been converted into plantations and restore these forests"..

"There are governments and local reforestation initiatives organised and implemented in and around the Kinabatangan region, joining local communities, oil palm schemes, and eco-tourism in halting forest loss and playing an important role in reconnecting the forest. The reforestation projects and protection against further expansion of oil palm plantations will have a positive influence on the proboscis monkey populations, getting stronger and more stable with time. However, we need to act now, increase the reconnection between forest fragments and reestablish large strips of riparian forest along the main river and its tributaries if we want the proboscis monkey to continue striving in Sabah and attract tourists", concluded Laurentius.

Sime Darby Foundation is currently funding a 3-year project on proboscis monkey to Danau Girang Field Centre and Sabah Wildlife Department to carry out research and conservation work towards a better management of the proboscis monkey populations in Sabah. The project aims to produce a management plan for the proboscis monkey in Sabah.

Notes to Editor

1. The paper "Modeling population viability of local proboscis

monkey Nasalis larvatus populations: conservation

implications" is published in the January 2012 edition of ENDANGERED SPECIES RESEARCH

Danau Girang Field Centre: Is a field study centre located within the Lower Kinabatangan and is a collaborative project between Cardiff University and the Sabah Wildlife Department. Studies on the ecology and genetics of the orang-utan, Bornean elephant, proboscis monkey and long-tailed macaque are ongoing, involving Cardiff University, Universiti Malaysia Sabah, HUTAN, WWF Malaysia and other collaborators.

Sabah Wildlife Department: All wildlife in Sabah is under the purview of this Department including the Lower Kinabatangan Wildlife Sanctuary.

Cardiff University: Cardiff University is recognised in independent government assessments as one of Britain’s leading teaching and research universities. Founded by Royal Charter in 1883, the University today combines impressive modern facilities and a dynamic approach to teaching and research. The University’s breadth of expertise in research and research-led teaching encompasses: the humanities; the natural, physical, health, life and social sciences; engineering and technology; preparation for a wide range of professions; and a longstanding commitment to lifelong learning. Cardiff is a member of the Russell Group of Britain’s leading research universities.

The University website is at:

For more information, please contact:

Dr Benoit Goossens

Director of the DGFC and a co-author on the paper

Email: or

Danica Stark

PhD student Cardiff School of Biosciences and lead paper author


Jill Wilmott-Doran
Public Relations Office
Cardiff University
029 2087 0298