A pan-African spatial assessment of human conflicts with lions and elephants

The escalating rate of species extinction, particularly affecting large mammals, is largely driven by habitat loss, unsustainable use, and human-wildlife conflict. The encroachment of human activities into wildlife habitats intensifies these conflicts, resulting in human injury and death, economic damage to crops and livestock, and diminished psychological well-being. This often reduces local support for conservation and leads to retaliatory killings of wildlife. Mitigation strategies vary from directly targeting wildlife (e.g., culling, translocation) to indirectly addressing the conflict through increased tolerance for economic losses (e.g., compensation schemes). However, the large-scale effectiveness of these approaches remains debated. Africa, a major stronghold for large mammals, faces growing human population and agricultural expansion, exacerbating human-wildlife conflict, particularly involving lions and elephants. These species have experienced range contractions and population declines due to habitat loss, hunting, and retaliatory killings. Mitigation fences are considered effective in some areas but raise concerns about habitat fragmentation. This study aims to identify high-risk conflict areas and assess the cost-effectiveness of high-quality mitigation fences as a conflict-mitigation strategy, considering potential ecological impacts.

Existing literature highlights the severity of human-wildlife conflict and the challenges in implementing effective mitigation strategies. Studies show the financial and social costs of crop raiding by elephants and predation by lions, impacting food security and well-being. The effectiveness of various mitigation techniques, such as culling, translocation, compensation schemes, and improved livestock husbandry, remains inconsistent and often context-specific. Several studies emphasize the importance of local community support for conservation success. The debate surrounding mitigation fences focuses on their economic viability and potential negative consequences for wildlife movement and landscape connectivity. While concerns exist about habitat fragmentation, these concerns are often associated with less strategically planned fencing. This review underscores the need for a comprehensive, spatially explicit assessment of conflict risk to inform effective and sustainable mitigation strategies.

This study combined the most recent distribution data for lions and elephants with spatial information on human population density, cropland, and cattle density – key drivers of conflict. Areas within 10 km of the highest densities of these factors along the species range perimeters were identified as high-risk areas. The species ranges were extended to include adjacent protected areas historically within their range, to avoid misinterpreting naturally occurring range boundaries with current human-influenced boundaries. Socio-economic and political variables influencing lion and elephant populations were considered, and the potential impacts of fences on migratory mammals were assessed. The equivalent annual annuity (EAA), a measure of the constant annual cash flow from a project, was used to estimate the return on investment from constructing and maintaining mitigation fences. The analysis considered costs of fence construction and maintenance, reduction in cattle loss, and crop damage. Sensitivity analyses explored the robustness of the findings to variations in buffer distances and random variations in the distance between species ranges and human pressure maps. The certainty of lion and elephant presence was also assessed, focusing on areas within protected areas where presence is more certain. Fragmentation analyses evaluated the impact of fences on migratory mammals using perimeter length-to-area ratios.

The analysis revealed that 82% of sites with lions and elephants are adjacent to areas with substantial human pressure. Around 60% of the range perimeters are near high densities of humans, crops, or cattle. Severe risk areas, where high human, crop, and cattle densities overlap, comprise 9% (approximately 10,000-12,000 km) of the perimeter and are distributed across 18 countries holding ~74% of the lion population and 41% of the elephant population. High-risk areas (high human population density plus high crop or cattle density) constitute an additional 10% of the perimeter across 26 countries. Countries with severe and high risks host 95% of Africa’s lions and 66% of its elephants. Sensitivity analyses confirmed the robustness of the findings across different buffer distances and random variations in distance calculations. Mitigation fences in severe conflict areas are unlikely to significantly increase fragmentation for most migratory mammals, with minor exceptions such as Grévy's zebra and Thomson's gazelle. Economic analyses using EAA indicated that building and maintaining mitigation fences in severe risk areas would likely provide a net return on investment in all 18 countries except South Sudan, with the highest returns expected in Tanzania, Ethiopia, and Kenya. In contrast, fencing in high-risk areas would seldom generate sufficient return on investment. Per capita benefits were highest in Benin, South Africa, and Zambia. There are approximately 25,125 lions and 415,428 elephants left in Africa.

The findings highlight that lions face a greater risk of conflict than elephants, with 74% of the lion population potentially at risk of decline or local extinction without intervention. While elephant populations are relatively high in low human-density areas, projected human population growth will likely increase conflict risks. The study demonstrates that mitigation fences offer a cost-effective conflict-mitigation strategy in high-risk areas, particularly for reducing livestock losses and crop damage. This could enhance tolerance towards wildlife and improve human-wildlife coexistence. However, in areas with lower conflict levels, alternative strategies focused on human dimensions may be more cost-effective. The economic analysis only considers direct benefits, neglecting the prevention of human injuries and deaths, which would further enhance the cost-effectiveness of fencing. Although large-scale human settlements already disrupt animal movements, careful consideration is needed to avoid further impeding ecological processes like migrations, especially for species like Grévy's zebra and Thomson's gazelle. Opportunities exist to restore ecological processes by removing existing fences in some areas, such as South Africa, Botswana, and Namibia.

This pan-African assessment underscores the urgent need for effective human-wildlife conflict mitigation. Mitigation fences represent a viable strategy in severe conflict areas, offering economic benefits and potentially enhancing wildlife conservation. However, careful planning is essential to minimize negative ecological impacts and ensure community acceptance. Future research should integrate human dimensions more holistically, exploring community perspectives and preferences regarding mitigation strategies, particularly in areas beyond protected areas. Collaboration with local communities is crucial for ensuring the long-term success of conflict-mitigation efforts. The COVID-19 pandemic's impact on wildlife-based tourism has exacerbated the need for urgent action and investment in sustainable conservation.

The study acknowledges limitations related to data quality. Species range maps represent coarse-resolution boundaries, and financial costs of mitigation might vary geographically due to data unavailability in some regions. The economic analysis assumes that financial benefits return to local stakeholders, neglecting the costs imposed on local people by fences (e.g., restricted access). The study provides a continent-wide assessment and should not be considered a precise local-scale blueprint. Local consultations are vital for adapting strategies to local contexts and gaining community support.