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by Allison Hanes

Indonesia serves as a good example of a country where the landscape is changing and in turn affecting wildlife and people.  Forests are being cut down at alarming rates for agricultural demands such as the palm oil industry.  Palm plantations cover 3,107,986 hectares of Indonesia and the government plans to expand plantations by an extra four million hectares in Sumatra alone.

The monoculture of palm decreases wildlife habitat and food resources pushing wildlife closer to human settlements.  Continuous forest conversion for the purpose of plantation development, wood extraction, and the opening of community gardens has virtually eliminated all lowland habitats.  This forces animals like the International Union for Conservation of Nature (IUCN) endangered Sumatran elephant Elephas maximus sumatranus to forested slopes of mountain ranges where they more often will enter gardens and raid crops.

Many studies state that wildlife habitat destruction is the greatest cause for the occurrence of crop raiding.  At the same time like many parts of the world population growth is soaring which also increases wildlife and human niches to overlap.  Indonesia is a region of high human population density having the sixth largest human population in the world.  Lee & Priston (2005) state that there has been a spread of agriculture and human activity into areas that used to only be sustained by nonhuman primates and that most of the world’s subsistence farmers live in proximity to monkeys and apes.  Wildlife continually being forced to move will increase the scale and extent of encounters between humans and wildlife as well as crop raiding.

Journal articles were chosen specifically on crop raiding of all species in Indonesia but some references included general articles about Indonesia and other case examples in the world such as Africa.  Most crop raiding studies have been done in Africa.  Indonesia was an interesting location because of its high human population density, rapidly declining forests, and large variety of species that come into contact with crops.

Hockings (2009) describes crop raiding as wildlife venturing into cultivated areas to consume foods that humans see as belonging to them.  It can be an adaptation by wildlife to a loss of both natural habitat and wild foods and also an increase in access to new energy-rich food resources.  A study in four villages in North Sumatra showed that crop raiding by wildlife was reported by 94.9% of the interviewees as the single most important determinant of crop yields.  Thirteen vertebrates were reported causing damage to cultivars.  The most common were squirrels, porcupines, pigs, deer, elephants, and primates.  The ones perceived to be the most destructive were the primates.  Almost all families of nonhuman primates are shown by Lee & Priston (2005) to be crop raiders, cercopithecoids such as macaques being the largest culprit.  This is thought to be because they are intelligent opportunistic frugivores.  In addition, they often live near forest-edges.

Crop damage caused by raiding wildlife is a prevalent form of human-wildlife conflict along protected area boundaries and near logged areas on forest borders.  Primates tend to dominate as the major pests around reserves in Asia, responsible for over 70% of damage events.  Macaques on the Mentawai Islands comprise up to 35% of garden yield losses.  Macaques and other primates are clever, opportunistic, adaptable, and often manipulative.  Crop raiding is often an easy option for them.  In Way Kambas National Park, Sumatra wild elephants damaged 450,000 square meters of corn, rice, cassava, beans and other annual crops as well about 900 coconut, banana, and other perennial trees over an 18 month survey study of 13 villages.  Within a 12-year period elephants killed or injured 24 people near the park.

Specific culprits mentioned in the articles that raided Indonesian crops included wild boars (Sus scrofa), Thomas’ leaf monkeys (Presbytis thomasi), long tailed macaques (Macaca fascicularis), orangutans (Pongo abelii), tonkean macaques (Macaca tonkeana), Sumatran elephants (Elephas maximus sumatranus), Pagai Island macaques (Macaca pagensis), and sun bears (Helarctos malayanus).  Different species specialize in different crops and even plant parts of crops or development stages. Not just primates are known to cause severe damage.  Primates may be agile but elephants cause a great deal of damage due to their large size and nocturnal/crepuscular activity.  Raiding patterns can relate to population density, behavior of the species, wild food availability, rainfall, season, and proximity of farms to forests.  All these factors affect raiding frequency and intensity, which play a large role in the livelihoods of people and how they perceive wildlife.

Crop raiding can have large impacts on people such as human lives lost in human-elephant conflicts.  As seen from statistics above crop raiding can have large impacts on the livelihoods of farmers.  They experience devastating economic losses when crops are their only source of income.   Crop raiding impacts time spent away from tending crops in order to carry out mitigation techniques like guarding.  Schooling of children is disrupted in order to help guard family crops.  There is also risk of injuries and disease transmission from wildlife.

The perceptions of local people toward wildlife crop raiding species are extremely important for mitigating crop raiding and for wildlife conservation.  Areas with less human wildlife conflict and crop raiding as well as better management tended to perceive wildlife more positively and were more tolerant.  People said that they enjoyed seeing wildlife and having them around for their children especially if they were not damaging crops.  Riley & Priston (2010) observed farmers tolerating crop raiding because they saw macaques as helping them harvest crops like cashew nuts.  A Butonese farmer stated ,“ they eat only the fruit, letting the nut drop to the ground for us to collect.”  In the Mentawai Islands in Sumatra nonhuman primates are seen as “cousins” and magical sources of spirit and life force, and were believed to play integral roles in the governing system of Mentawai life cycle.  In Bali monkeys are treated with great tolerance because the Balinese culture emphasizes harmony between nature and mankind.  Tokean macaques have been regarded as kin and guardians although still feared.  Seeing the animals when they were not actively crop raiding resulted in more positive perceptions of the animals.

However, local people often reported being threatened both in terms of crop loss and personal safety.  People felt more at risk with larger species such as elephants and primates despite whether raidings were rare for that species.  For example, studies showed that people feared orangutans much more than smaller species and perceived them to cause the most damage even when it was not the case.  Articles continually showed fear of wildlife and often local legends of primates kidnapping women or children like that of the Sumatran orangutan which resulted in “an offspring which is restricted to the treetops and in the night you can still hear the cries of the this human-half-orangutan.”  If farmers and families felt they were in no physical threat they were more tolerant.

Mitigation techniques included fences, electric fences, dogs, chemical deterrents, taste aversion conditioning, playback alarms, guarding/chasing, noise/bells/shouting, contraception, painting individuals, stones/slingshots/spears, shooting/hunting, trapping/culling, translocation, change cropping patterns, and buffer zones.  All of which can be used in different contexts with advantages and disadvantages.  Shouting is often the most common.

Linkie et al. (2006) states that guarding is completely ineffective for a variety of species whereas Hedges & Gunaryadi (2010) concluded community-based guarding using conventional tools was more effective and less costly than sirens and chilli-grease fences in Way Kambas National Park.  However, the chillies could serve as an alternate elephant-resistant cash crop.  Lee & and Priston (2005) state traditional methods of mitigation are often ineffective because of dexterity and intelligence of primates.  Techniques largely depend on the crop raider and the region.  Many of the techniques are very costly and time consuming to farmers.  More research needs to be invested in monitoring techniques that are utilized.  Incorporating local input and views will have longstanding effective crop-raiding solutions.  Cooperation of local people is necessary to control pests and conserve wildlife.  Lee & Priston (2005) state that information about the attitudes and perceptions of wildlife as pests is a prerequisite to designing optimal and effective management schemes and introducing suitable preventative measures.

Education programs and community meetings that initiate management schemes are necessary.  Ecotourism can also be a used to supplement income to farmers and lessen tension between people and wildlife.  The value of forests to people and wildlife must be addressed.  Campaigns and policies lessening the rates of deforestation will decrease habitat overlap and crop raiding issues between people and wildlife.

As forests are cleared for demands in agricultural expansion and population growth continues to rise, human and wildlife habitats in Indonesia will continue overlapping.  Human wildlife interactions will increase as will the incidence of crop raiding.   Mitigation techniques have proved very difficult due to limited resources of famers and intelligence of animals.  Each location and species presents a particular scenario with different factors affecting the intensity and occurrence of crop raiding that will require unique methods or a combination of tactics.  Therefore, if crop raiding cannot be eradicated, it certainly must be minimized and managed to reduce conflict.  People’s perceptions are particularly important because crop raiding can reduce tolerance toward wildlife and affect actions taken by local farmers.  Local people play the key role in generating sustainable solutions and for conserving wildlife.