Surviving strategies in the Sahara: Understanding diel activity patterns of ungulates in hyper-arid regions

Abstract

Diel activity patterns provide insight into how animals adapt to environmental constraints, human disturbance, and community context. However, empirical information on diel activity of large, free-ranging ungulates in hyper-arid systems is limited, and much of the existing evidence comes from fenced enclosures or managed reserves. To investigate these mechanisms, we used Cuvier's gazelle (Gazella cuvieri) as a model species to examine seasonal and ecological drivers of activity in a hyper-arid Saharan landscape. A total camera trap effort of 11 333 trap days was accumulated across four sites. We studied both abiotic (seasons, moon phase, and rainfall) and biotic factors (activity of the African golden wolf, Barbary sheep, and livestock). The influence of each factor was assessed using the activity overlap coefficient (∆) and the non-parametric circular Mardia–Watson–Wheeler test. Period selection within the diel cycle was analysed using chi-square contingency tables and the ‘Wi’ parameter of the resource selection coefficients. Cuvier's gazelle exhibited predominantly diurnal activity with bimodal crepuscular peaks at dawn and dusk and reduced activity at midday. The main drivers were wet/dry periods and moon phase. In contrast, intra-guild factors did not produce significant effects, although temporal asynchrony with wolves and slight behavioural shifts in the presence of livestock were observed. Overall, gazelles avoided nocturnal hours and selected crepuscular periods. These findings strengthen our understanding of behavioural adaptations of an endangered species in hyper-arid environments and contribute to broader knowledge of ungulate activity patterns under extreme ecological constraints.