Changing seasonal, temporal and spatial crop-raiding trends over 15 years in a human-elephant conflict hotspot

Human-wildlife conflict is increasing due to rapid natural vegetation loss and fragmentation. We investigated seasonal, temporal and spatial trends of elephant crop-raiding in the Trans Mara, Kenya during 2014–2015 and compared our results with a previous study from 1999 to 2000. Our results show extensive changes in crop-raiding patterns. There was a 49% increase in incidents between 1999 -2000 and 2014–2015 but an 83% decline in the amount of damage per farm. Crop-raiding went from highly seasonal during 1999–2000 to year-round during 2014–2015, with crops being damaged at all growth stages. Additionally, we identified a new elephant group type involved in crop-raiding, comprising of mixed groups. Spatial patterns of crop-raiding also changed, with more incidents during 2014–2015 neighbouring the protected area, especially by bull groups. Crop-raiding intensity during 2014–15 increased with farmland area until a threshold of 0.4 km2 within a 1 km2 grid square, and farms within 1 km from the forest boundary, 2 km from village centres were most at risk of crop-raiding. In the last 20 years the Mara Ecosystem has been impacted by climate change, agricultural expansion and increased cattle grazing within protected areas. Elephants seem to have responded by crop-raiding closer to refuges, more frequently and throughout the year but cause less damage overall. While this means the direct economic impact has dropped, more farmers must spend more time protecting their fields, further reducing support for conservation in communities who currently receive few benefits from living with wildlife

Assessing farm based measures for mitigating human elephant conflict in transmara District Kenya.

Crop raiding by elephants is widespread across Africa and Asia. Although many traditional and novel methods are used to defend farms there have been few rigorous tests of their efficacy. We provide a comparative quantitative assessment of a range of farm-based mitigation methods implemented during a 4-year project in Transmara District, Kenya. Five experimental trials were established to measure changes in crop raiding after the application of mitigation methods on treatment farms compared with control farms. A combination of early warning to detect elephants before they entered farms, coupled with a front line communal guarding strategy, proved most successful. Non-electrified barriers were expensive and generally ineffective. However, chilli Capsicum spp. grease applied to rope barriers encircling farms completely deterred elephants. Although encouraging, these results require more widespread testing and demonstration to ensure their effectiveness at broader scales

Factors affecting susceptibility of farms to crop raiding by African elephants: using a predictive model to mitigate conflict

1. Crop raiding by African elephants Loxodonta africana erodes local tolerance for elephants and thereby impedes conservation efforts, so solutions are urgently required. Within conflict zones, crop raiding is not distributed equally amongst farms, which may be a result of variation in local physical or geographical factors, or in farmers' efforts to defend their fields. Understanding the efficacy of local conflict mitigation methods is important, but few quantitative evaluations exist. 2. Using a comparative survey of raided and non-raided farms in Transmara District, Kenya, and multivariate logistic and linear regression analyses, we explored a range of factors affecting (i) the susceptibility of farms to elephant crop raiding and (ii) the amount of crop damage once elephants had entered a field. 3. The results revealed that farms that had been habitually raided in the past were more likely to be raided during the study period, as were those that were larger and bordered by hedges or fences. Greater guarding effort increased the likelihood that elephants were detected prior to entry and decreased the likelihood of successful crop raiding, as did the use of fire and noise. 4. However, there was an interaction between physical and human factors; larger farms used more advanced barrier methods at the expense of guarding effort. Farmers' efforts did not appear to diminish the damage inflicted once elephants had entered a field. 5. A subsequent experimental test confirmed these results; the application of enhanced early warning and guarding effort on previously raided farms reduced incidents of crop raiding by 89.6% over 2 years in comparison with a control group of farms. 6. Synthesis and applications. These results suggest that early detection of elephants approaching fields, increased guarding effort, and the use of active deterrents could form the basis of an effective mitigation strategy regardless of location and the physical attributes of a farm. Validating the results of predictive models through participatory mitigation trials serves to demonstrate effective solutions to farmers themselves. Researchers and practitioners should be encouraged to replicate such field trials over broader spatial and temporal scales and to find means to encourage farmers to take up appropriate solutions

Predicting spatial aspects of human-elephant conflict

1. Human-elephant conflict (HEC) in Africa occurs wherever these two species coincide, and poses serious challenges to wildlife managers, local communities and elephants alike. Mitigation requires a detailed understanding of underlying patterns and processes. Although temporal patterns of HEC are relatively predictable, spatial variation has shown few universal trends, making it difficult to predict where conflict will take place. While this may be due to unpredictability in male elephant foraging behaviour (the male behaviour hypothesis) it may also be due to variations in the data resolution of earlier studies. 2. This study tested the male behaviour and data resolution hypotheses using HEC data from a 1000-km(2) unprotected elephant range adjacent to the Masai Mara National Reserve in Kenya. HEC incidents were divided into crop raiding and human deaths or injuries. Crop raiding was further subdivided into incidents involving only male elephants or family groups. A relatively fine-resolution, systematic, grid-based method was used to assign the locations of conflict incidents, and spatial relations with underlying variables were explored using correlation analysis and logistic regression. 3. Crop raiding was clustered into distinct conflict zones. Both occurrence and intensity could be predicted on the basis of the area under cultivation and, for male elephant groups, proximity to major settlements. Conversely, incidents of elephant-induced human injury and death were less predictable but were correlated with proximity to roads. 4. A grid-based geographical information system (GIS) with a 25-km(2) resolution utilizing cost-effective data sources, combined with simple statistical tools, was capable of identifying spatial predictors of HEC. At finer resolutions spatial autocorrelation compromised the analyses. 5. Synthesis and applications . These results suggest that spatial correlates of HEC can be identified, regardless of the sex of the elephants involved. Moreover, the method described here is fully transferable to other sites for comparative analysis of HEC. Using these results to map vulnerability will enable the development and deployment of appropriate conflict mitigation strategies, such as guarding, early warning systems, barriers and deterrents. The utility of such methods and their strategic deployment should be assessed alongside alternative land-use and livelihood strategies that limit cultivation within the elephant range