Template:Chapters 7.11

7.11 - Replenishing food of wild animals to prevent crop damage

Katherine Trottier, University of Guelph, Canada

Suggested citation for this chapter.

Author name (2022) title of chapter. In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org

Introduction

Growing global populations put an increasing pressure on wildlife, and habitat loss is one of the major stresses. Humans and wildlife are now living in closer contact than ever before and human-wildlife conflicts are a major source of strain for both subsistence farmers and animal species. Crop-raiding is a significant problem affecting farmers; animals such as elephants (Loxodonta africana), wild boars (Sus scrofa), non-human primates, bears (Ursidae), and rhinoceroses (Rhinocerotidae) can be common culprits of crop-raiding. Not only does this pose a major threat to food sources and income for farmers, but it can also endanger wildlife. Human-elephant conflict is considered one of the top three threats to species survival (Gross et al. 2016). Wildlife can be a huge cause of financial losses, and their management is not an easy task. The problem of wildlife raids has been found to be exacerbated during the dry season when seasonal food shortages occur (Mwangi et al. 2016). One Kenyan village perceived their poverty was because of crop damage from wildlife. To protect crops, farmers may have little option but to continually guard their livestock and crops. This daytime task often falls on children, who

then cannot attend school (Mwangi et al. 2016). Other options used to manage wildlife included poisoning and shooting them.

Solutions for protecting crops from wildlife in non-lethal ways are not universal. There are many ways to dissuade wild animals from damaging crops or killing livestock. Possible solutions may include planting less desirable crops, providing an alternative food source of wildlife, installing barriers or using deterrents.

Planting less desirable crops

One way to prevent wildlife from crop-raiding is to plant crops that are low-conflict or that can be used symbiotically by farmers and animals. Certain crops are very desirable to different species; maize (Zea mays) is a very attractive crop to African elephants and wild boars (Gross et al. 2016). A study by Gross et al. (2016) tested alternative crops to see if they would be subjected to the same level of trampling and crop-raiding by elephants that maize was. Crops that contained essential oils (ginger, Zingiber officinale and lemongrass, Cymbopogon citratus) or had a strong scent (garlic, Allium sativum and onions, Allium cepa) were used as alternatives. Researchers found that lemongrass and ginger were good quality and harvestable at the end of their growing season. Ginger survived tramping much better than lemongrass did (Include this or no?). The study also found it would be ineffective to intercrop undesirable crops with desirable ones. However, elephants are extremely sensitive to chili peppers (Capsicum species) so bordering crops with chili pepper plants may be an exception. Mentha species have also been shown to be left undamaged by wildlife, as has tobacco (Nicotiana) and turmeric (Curcuma longa) (Thapa 2010). Wheat (Triticum ssp.) and barley (Hordeum vulgare) are much less attractive to wild boars than maize (Schley et al. 2008). Tea (Camellia sinensis) has also been shown to be unattractive to wildlife, and is an economically important crop globally (Hockings & Sousa 2012).

Methods of grazing and preferences should be considered when selecting alternative crop species. For example, elephants prefer to graze on material growing that is 100-200 centimetres in height (Mwangi et al. 2016). Shorter-growing crops would be less desirable. Tall crops like maize also offer hiding places for wild boars and other wildlife (Schley et al. 2008). Wildlife may feel more vulnerable without cover and be less inclined to crop-raid.

Cashews (Anacardium occidentalis) are an example of a cash crop that benefits both humans and wildlife, particularly chimpanzees (Pan troglodytes verus). While humans have an economic interest in harvesting the cashew nuts, chimpanzees are primarily interested in the fruit which is unprofitable to humans. Chimpanzees remove the nuts from the fruit as they eat, making harvesting the nuts easier for humans (Hockings & Sousa 2012).

Planting an alternative food source for wildlife

It is important to address why wildlife are trying to access crops and livestock. One possibility is that habitats have become depleted and fragmented, forcing animals to look elsewhere. Another opinion is that crops are nutritionally superior and more favourable than wild food due to their spatial density and foraging ease (Watve et al. 2016).

Replenishing food sources for wildlife may still not be enough to dissuade wildlife from targeting farms since they are a source of high-density nutrition. Supplemental feeding is often used for game species to alter behaviour and locations (Felton et al. 2016). This often leads to increases in population densities and a decreased foraging range (Cooper et al. 2006). A study done on wild boars in Luxembourg found that supplemental feeding did not lead to a decrease in crop damage except in rare circumstances (Schley et al. 2008).

Wild places could be restored to provide natural food sources if they have been depleted, combined with other management practises to dissuade animals from entering farmland. Wildlife corridors are an option to connect fragmented habitat.

Deterrents

Scaring devices and loud noises have also been shown to be very effective deterrents, at least initially. Wildlife can quickly become desensitized to scaring devices like loud noises. (Thapa 2010). Early-warning systems (such as cowbells strung up) can help farmers anticipate the arrival of some wildlife species. Watch towers remain consistently effective and are especially useful when encountering potentially dangerous animals like rhinoceroses and elephants (Thapa 2010).

Dogs have been used successfully for thousands of years as guardian animals. However, in the tropics they are much less effective especially in areas with large predatory mammals (Wong et al. 2015). They also have a low rate of adoption because of some religions believe them to be unclean. However, barking dogs may be a good substitute for human noise-making, allowing farmers to be more productive and children to attend school. The effectiveness of dogs may depend on the offending wildlife species, and the risk of harm they pose to dogs.

Full-strength ammonia has been shown to deter sun bears (Helarctos malayanus), so ammonia-soaked fabric placed around crops can help ward off bears when required (Wong et al. 2015). This may also deter other animals who rely on their sense of smell, including elephants.

Barriers

Barriers are used to restrict access to crops in the forms of fences or ditches. Living fences can be cultivated and be very effective at keeping out wildlife. Ipomoea species are recommended for keeping out smaller animals, and Euphorbia species for larger wildlife, including elephants and rhinoceroses. Euphorbia species are covered in thick thorns (Thapa 2010). These species will grow very densely and make it impossible to pass, thus making them a very effective solution. Drawbacks include a long duration to grow the fence, and eventual plant death. These are less effective with burrowing animals such as wild boars.

Interestingly, barbed wire fences were found to be very ineffective with all animal species (Thapa 2010). These can be damaged and destroyed and require maintenance. Electric fences often do not work as well and require constant maintenance. It has been observed that primates often navigate across them, and elephants have been known to knock trees onto them to cross (Mwangi et al. 2016).

Chili fences have been used with good success. These are constructed by applying chili grease (from Capsicum spp.) and engine oil on rope fences surrounding the property. A compound in the chili grease causes an unpleasant odour which dissuades animals, like elephants, from entry. One study by Sitati et al. (2006) found that a 1.4 km rope fence prevented elephants from crop raiding for a period of weeks. However, the elephants eventually travelled to the ends of the fence and walked around (Sitati et al. 2006). The same study found that a farm fully fenced with chili ropes was able to deter elephants for at least two years, despite numerous attempts at crop raiding. Chili grease should be applied at least once a week to remain effective.

Trenches can be an effective solution when regularly maintained for smaller wildlife; they are less effective with elephants. When the trenches become filled with leaves and debris, they are not as useful (Sitati et al. 2006)

Critical Analysis

Changing cropping systems may not be a viable long-term solution; after a while, wildlife may grow accustomed to the new crop and begin eating it as well. This was shown in a village where sugarcane cultivation was recommended due to a high conflict with wild boars. After a few years, the boars began to eat the new crop (Thapa 2010). For subsistence farmers, planting alternative crops may not be as practical if markets are not easily accessible to sell them. This would depend on the crop and its usefulness as a staple food crop. Some alternative crops may require irrigation systems which may not be in place in remote villages (Thapa 2010).

Many problems can arise from supplemental feeding of wildlife, including alteration of population genetics or demography of the species (Felton et al. 2017). This can have a ripple effect on the surrounding forest environment. It has found to be an inefficient way of preventing crop-raiding. It can also result in nutritional imbalances in wildlife which can lead to declining health of the local population, and possibly put them at risk (Felton et al. 2017). If food is supplemented to wildlife, the targeted species should be offered food sources that closely resemble their natural diets. This would most likely be most effective when used in conjunction with deterrents.

The use of chili grease may be cost prohibitive for subsistence farmers unless peppers are grown locally. This may present a business opportunity if agronomic conditions are suitable for chili farming. Deterring wildlife may also shift them to neighbouring farms that are unprotected. Finally, effective defense of cropland may increase the usage of land for agriculture. While this may benefit humans, it reduces natural foraging habitat for wildlife and will eventually exacerbate the issue in the future and create further problems for wildlife. Proper land stewardship is essential.

Picture Based Lesson to Train Farmers

Click on the image to access a higher resolution image as well as lessons adapted for different geographic regions.

Resources for NGOs

Chili seeds can be purchased online from Alibaba.com, (Access online at: https://www.alibaba.com/showroom/hot-pepper-seeds.html) Where to get seeds for aromatic herbs and trample-resistant varieties

How to build chili fences: (Access online at: http://www.resolv.org/site-BiodiversityWildlifeSolutions/files/2014/12/HEC-Chilli-Fence-Manual-World-Animal-Protection-2015.pdf)

References

1. Cooper, S. M., Owens, M. K., Cooper, R. M., & Ginnett, T. F. (2006). Effect of supplemental feeding on spatial distribution and browse utilization by white-tailed deer in semi-arid rangeland. Journal of Arid Environments. 66(4): 716-726.

2. Felton, A. M., Felton, A., Cromsigt, J. P. G. M., Edenius, L., Malmsten, J., & Wam, H. K. (2017). Interactions between ungulates, forests, and supplementary feeding: the role of nutritional balancing in determining outcomes. Mammal Research. 62: 1-7.

3. Gross, E. M., McRobb, M., & Gross, J. (2016). Cultivating alternative crops reduces crop losses due to African elephants. Journal of Pest Science. 89(2): 497-506.

4. Hill, C. M., & Wallace, G. E. (2012). Crop protection and conflict mitigation: reducing the costs of living alongside non-human primates. Biodiversity Conservation. 21: 2569-2587.

5. Hockings, K. J. & Sousa, C. (2012). Differential utilization of cashew –a low-conflict crop – by sympatric humans and chimpanzees. Fauna and Floral International. 46(3): 375-381.

6. Mwangi, D. K., Akinyi, M., Maloba, F., Ngotho, M., Kagira, J., Ndeereh, D., & Kivai, S. (2016). Socioeconomic and health implications of human-wildlife interactions in Nthongoni, Eastern Kenya. African Journal of Wildlife Research. 46(2): 87-102.

7. Ranjan, R. (2017). Tuskers, tasty crops, and forest tribes in between: managing HECs through financial incentives in human-elephant-forest ecosystems. Journal of Environmental Economics and Policy. 6(1): 79-95.

8. Schlageter, A., & Haag-Wackernagel, D. (2012). Evaluation of an odor repellent for protecting crops. Journal of Pest Sciences. 85: 209-215.

9. Schley, L., Dufrene, M., Krier, A., & Frantz, A. C. (2008). Patterns of crop damage by wild boar (Sus scrofa) in Luxembourg over a ten-year period. European Journal of Wildlife Research. 54: 589.

10. Sitati, N. W. & Walpole, M. J. (2006). Assessing farm-based measures for mitigating human-elephant conflict in Transmara District, Kenya. Oryx. 40(3): 279-286.

11. Thapa, S. (2010). Effectiveness of two crop protection methods against wildlife damage: a case study of two villages at Bardia National Park, Nepal. Science and Technology Policy Research. 29: 1297-1304.

12. Watve, M., Bayani, A., & Ghosh, S. (2016). Crop damage by wild herbivores: insights obtained from optimization models. Current Science. 111(5): 861-867.

13. Wong, W. M., Leader-Williams, N., & Linkie, M. (2015). Managing human-sun bear conflict in Sumatran agroforest systems. Human Ecology. 43: 255-266.