Identification of key landscape drivers of range size and range shifts in African savanna elephants in northern Kenya

Context
Drivers of animal ranging behavior are diverse and often dynamic in changing landscapes. Understanding correlates of home range sizes and shifts can reveal factors influencing wildlife populations and offer insights into responses to environmental change.

Objectives
We investigated drivers of African savanna elephant multi-year, annual, and seasonal range sizes and shifts.

Methods
We estimated annual and seasonal range sizes, range shifts, and their correlates using a 20-year tracking dataset (110 elephants) in northern Kenya, allowing diagnosis of drivers of range use and change.

Results
Home range sizes varied widely across sampled individuals (average AKDE core area = 839.62 km2, SD = 1483.09 km2, and home range = 3567.37 km2, SD = 6066.05 km2). Individuals’ annual and overall seasonal ranges overlapped strongly, with the greatest shifts between dry and wet seasons. Smaller annual home ranges were associated with higher mean rainfall and water availability, whereas larger ranges were correlated with rainfall variability. Seasonal core areas were smaller with higher productivity (normalized difference vegetation index, NDVI), surface and permanent water, elevation, but larger with increasing terrain ruggedness (TRI), human modification, and NDVI variability. Individuals’ annual and seasonal overlap increased with TRI; seasonal shifts were greater with high human modification. Dry-to-wet overlap increased with seasonal water, wet-to-dry overlap increased with rainfall variability but decreased with mean rainfall.

Conclusions
Water, terrain, and human impacts were key factors shaping elephant space use. This longitudinal study highlights the influence of human land-use changes on elephant behavior and underscores the need for effective resource management, particularly water management, for elephant conservation.