As human populations encroach into wildlife habitats to meet their livelihood needs, competition for space and resources leads to increased levels of conflict between the two1 . Indonesia is losing massive amounts of forest cover per year2 , with virtually the entire rainforest habitat of orangutans exploited to some extent3.

Forest cover on Sumatra was reduced by 48% from 1985-2007 due to logging, infrastructure projects, internal migration, and plantation development 4,5 . There are now less than 864,100 hectares of Sumatran orangutan habitat left, and the trajectory remains downward6.

The Sumatran orangutan has experienced a drastic decline in population, with the most recent survey reflecting just  6,600 left in the wild, from an estimated 85,000 in 19006. With the expansion of agricultural developments into  forested lands, incidents of HOC can only be expected to increase, also exposing orangutans to higher levels of hunting and poaching for the pet trade7,8,9.

The Human Orangutan Conflict Response Unit (HOCRU) has been working in communities adjacent to the GLNP since 2010, conducting human-wildlife conflict mitigation, mapping areas of reported/potential conflict, and educating people on best practice methods of mitigation and prevention. Thus far the team has responded to 48 cases of  orangutans crop-raiding, safely moving them back into the GLNP. Furthermore, the team has encountered and  subsequently helped rescue 7 orangutans that were being held illegally in the areas visited.

This project addresses the problem of human conflicts with the critically endangered Sumatran orangutan (*Pongo abelii*) inagricultural landscapes adjacent to the Gunung Leuser National Park (GLNP), Sumatra, Indonesia. The Human Orangutan Conflict Response Unit (HOCRU) is a roving team that responds to conflict situations and reports of crop-raiding in agricultural areas across northern Sumatra. Forest-adjacent communities affected by human-orangutan conflict (HOC) are offered training in best-practice methods of safely and humanely protecting their crops from orangutans, and data is collected regarding the extent and severity of this problem.

Resolving HOC is a conservation imperative because Sumatran orangutans are amongst the most threatened primate species in the world1 . The nature, causes, and possible solutions to HOC have recently been named as important practical questions in need of answers2 . The HOCRU is a specialist unit addressing this problem, and administering direct, immediate help to these critically endangered apes in conflict situations.

The Indonesian government’s National Action Plan 2007-2017 for the orangutan considers human-orangutan conflict to be a priority area for intervention3 . Several other policies also refer to the need to address this problem, including the 2004 North Sumatra decree (No.522.51/2235.K), and the National Ministry of Forestry 2008 decree (Regulation No.48). As part of our programme, an additional province-wide decree was issued in North Sumatra in 2011 (Governor Decree No.188.44/536/KPTS/2011). This programme is therefore tackling a problem that is recognised as a serious threat to the survival of orangutans.

1. Mittermeier RA, (2009) Primates in Peril: The World’s 25 Most Endangered Primates 2008–2010. Arlington, VA: IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS), Conservation International (CI).
2. Meijaard E, et al. (2011) Not by science alone: why orangutan conservationists must think outside the box. Annals of the New York Academy of Sciences: The Year in Ecology and Conservation Biology
3. Soehartono T, et al. (2009) Orangutan Indonesia: Conservation Strategies and Action Plan 2007-2017. Directorate General of Forest Protection and Nature Conservation, Ministry of Forestry of the Republic of Indonesia, Indonesia Primate Association (APAPI), and Orangutan Conservation Services Program (OCSP).
4. Madhusudan MD (2003) Living amidst large wildlife: Livestock and crop depredation by large mammals in the interior villages of Bhadra Tiger Reserve, south India. Environmental Management 31: 466-475.
5. Gaveau DLA, et al. (2009) The future of forests and orangutans (*Pongo abelii*) in Sumatra: Predicting impacts of oil palm plantations, road construction, and mechanisms for reducing carbon emissions from deforestation. Environmental Research Letters 4: 1/11.
6. Husson S, et al. (2009) Orangutan distribution, density, abundance and impacts of disturbance. In: Wich SA, Utami Atmoko SS, Mitra Setia T, van Schaik CP, editors. Orangutans: Geographic variation in behavioral ecology and conservation. Oxford: Oxford University Press.pp. 77-96.
7. Laumonier Y, et al. (2010) Ecofloristic sectors and deforestation threats in Sumatra: identifying new conservation area network priorities for ecosystem-based land use planning. Biodiversity Conservation 19: 1153–1174.
8. McConkey K. (2005). Sumatran orangutan (*Pongo abelii*). In World Atlas of Great Apes and their Conservation. (ed. J. Caldecott & L. Miles), pp. 184-204: University of California Press.
9. Wich et al. (2011) Orangutans and the Economics of Sustainable Forest Management in Sumatra. UNEP/GRASP/PanEco/YEL/ICRAF/GRID-Arendal.
10. Brown E, Jacobson M (2005) Cruel Oil: How Palm Oil Harms Health, Rainforest and Wildlife. Washington: Centre for Science in the Public Interest.
11. Shepherd C, Sukumaran, J, Wich S (2005) Open season: An analysis of the pet trade in Medan, Sumatra 1997-2001. Traffic Southeast Asia.
12. Hadisiswoyo P (2008) Orangutans and Farmers: A Perceived Human-Orangutan Conflict study in seven villages near Gunung Leuser National Park, Sumatra, Indonesia. School of Social Sciences and Law, (unpublished) MSc thesis. Oxford Brookes University

The Human Orangutan Conflict Response Unit (HOCRU)