Movement patterns of African elephants (Loxodont africana, Blumenbach) in a seasonally variable ecosystem in south-eastern Chad
African elephant (Loxodonta africana) range and numbers have declined over the past century as a result of increasing human populations, agricultural development, and illegal hunting for ivory. Understanding the dynamics of wide-ranging animal migrations is important for the conservation of these species and their habitats in a rapidly changing world. The study of movement has greatly advanced in the past few decades and novel approaches for characterizing and interpreting complex movement data, predominantly collected through telemetry, have emerged. The Zakouma National Park elephant population has declined dramatically over the past ten years due to rampant ivory poaching. Several elephants in this population were fitted with satellite collars between 2011 and 2012. The telemetry data collected from these animals, in combination with data collected from the same population ten years earlier, provides spatiotemporal movement data from before and after a period of severe poaching. Broad scale shifts in seasonal movement patterns between these two time frames were explored. Movement behaviour was analysed at a finer spatial and temporal scale by comparing the rate of movement within different areas, during the day and night. A spatially-explicit approach for characterizing movement behaviour within discrete grid squares was used to identify seasonal patterns in the distribution of movement behaviour indicative of stress. After ten years of highly stressful poaching conditions, extensive seasonal migrations to the north and west of Zakouma National Park persist. At a finer spatial scale movement behaviour indicative of human-induced stress has emerged, especially in the areas utilized to the north of the park. Elephant behaviour to the north of Zakouma, particularly in response to the main road intersecting this area, suggests that barriers to dispersal may soon arise. Furthermore, the absence of migration in the wet season of 2013, after the data cut-off point for this study, suggests that the migration behaviour of this elephant population may be changing. In light of these findings, land-use planning in this area should be carried out in order to realign the boundaries of protected areas to include important elephant dispersal areas.
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Percy FitzPatrick Institute of African Ornithology