The 2020 elephant die-off in Botswana

Area of Science:

• Wildlife Ecology
• Conservation Biology
• Veterinary Epidemiology

Background:

• Unexplained mortality of 350 elephants in northern Botswana in 2020 raised concerns.
• Media speculation on causes overlooked ecological factors and conservation implications.
• Elephant population dynamics are influenced by factors within the Kavango-Zambezi Transfrontier Conservation Area.

Purpose of the Study:

• To investigate the unknown cause of a large elephant die-off in Botswana.
• To address ecological and conservation issues related to elephant management.
• To counter detrimental media speculation with evidence-based analysis.

Main Methods:

• Ruled out malicious poisoning and poaching based on intact tusks and unaffected other species.
• Considered water scarcity and potential blue-green algae contamination as possible but unproven factors.
• Identified contagious disease as a more probable cause for the elephant deaths.

Main Results:

• The die-off was confined to a specific area, suggesting localized factors like fences and water channels played a role.
• These confinement factors likely contributed to a high elephant population growth rate despite past poaching.
• While the deaths were ~2% of the local population, they highlight the impact of human-wildlife conflict and habitat fragmentation.

Conclusions:

• Contagious disease is the most probable cause for the elephant mortality event.
• Habitat confinement and high elephant densities likely exacerbated the situation.
• Recommendations include re-aligning or removing fences to improve elephant movement and freshwater access.