Using simulations of past and present elephant (Loxodonta africana) population numbers in the Okavango Delta Panhandle, Botswana to improve future population estimates
2015
Songhurst, Anna | Chase, Michael | Coulson, Tim
An ability to reliably estimate population numbers, trends and densities of wildlife has a prominent role in conservation and management of wetlands. We use aerial surveys and simulation techniques to explore the results of past and present elephant population surveys in the Okavango Delta Panhandle, Botswana, and use these to propose a technique of simulation to improve counts in the future. Population numbers and density estimates from past survey results show large fluctuations, which are unlikely to come from reproduction. Reasons for such variations could be attributed to imprecision in survey techniques or may be because only part of the elephant range is being surveyed. Simulated surveys of hypothetical elephant populations were used to explore the effect of different survey techniques, spatial distributions of animals and spatial scale on the precision of aerial survey population estimates and trends. Our study reveals the usefulness of using simulations to test the reliability of survey data and plan more efficient surveys. We also find that while there may be some uncertainty in individual population estimates, there is more certainty in the recorded trends. These findings reinforce the need to address elephant management in the Okavango and surrounding wetland systems and call for the urgent consideration of management strategies such as fence realignments to affect the objectives of the Kavango Zambezi Transfrontier Conservation Area (KAZA TFCA) initiative, which will help relieve elephant population pressure.
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