Environmental and Anthropogenic Drivers of Giraffe Occurrence and Relative Abundance in a (…)

ABSTRACT

This study examines how reticulated giraffe (Giraffa reticulata) respond to the combined effects of climate variability and human land use in a fragmented savannah system. The research was conducted in Loisaba Conservancy, Kenya, a multi-use rangeland where wildlife coexists with pastoral livestock under increasingly variable climatic conditions. Using 6 years of camera-trap data (2016–2021), we assessed how environmental factors, human activity and vegetation dynamics influence giraffe occurrence, relative abundance and short-term space use. Giraffe presence and relative abundance were modelled using generalised linear mixed models that incorporated habitat features, livestock activity, seasonal and annual variation and satellite-derived vegetation indices. Giraffe occurrence was most strongly associated with escarpment habitats and with areas of high livestock activity, indicating substantial spatial overlap between giraffe and pastoral land use. However, relative abundance was shaped by a combination of livestock presence, distance from the conservancy boundary, slope, and proximity to water and showed strong interannual fluctuations. Contrary to expectations, short-term vegetation greenness, measured using MODIS NDVI, did not predict giraffe occurrence or relative abundance. Instead, giraffe photo rates declined when vegetation deviated from its typical annual peak, whether due to drought or unusually wet conditions. This suggests that giraffes are more sensitive to climatic extremes than to short-term changes in forage availability. Analysis of activity patterns and site recolonisation revealed fine-scale temporal avoidance of livestock. Although giraffe and livestock were active at similar times of day, giraffe were far less likely to return to a camera-trap site within 12 h after livestock had been present. This indicates that giraffe and livestock coexist spatially but partition their use of space over time. Overall, this study shows that giraffe space use in human-dominated savannahs is driven more by habitat structure and interannual climate variability than by immediate vegetation conditions. The results emphasise the importance of structurally complex interior habitats and climate-buffered refuges for conserving reticulated giraffe in a mixed-use landscape.