Plasticity in circadian activity patterns of mesocarnivores in Southwestern Europe: implications for species coexistence

Limiting similarity theory predicts that competing species must segregate along one or more dimensions of their ecological niche in order to coexist. In predator communities, interspecific interactions are influenced by a diversity of factors; therefore, the behavioural patterns of composing species will differ due to locally adapted interactions. We deployed 32-41 camera-traps in five study areas across the Iberian Peninsula to investigate the temporal relations between mesocarnivores in SW Europe. The selection for a period of the diel cycle and plasticity in activity patterns was evaluated using the Jacobs Selection Index (JSI) and the coefficient of activity overlap (a dagger(1)). Furthermore, we investigated whether temporal shifts can facilitate coexistence by reducing activity overlap. Seven species of mesocarnivores were detected and were assigned into one of three behaviourally distinct groups: diurnal (JSI(day) a parts per thousand yenaEuro parts per thousand 0.8), strictly nocturnal (JSI(night) a parts per thousand yenaEuro parts per thousand 0.8) or facultative nocturnal species (0.4 a parts per thousand yenaEuro parts per thousand JSI(night) > 0.8). Most species exhibited substantial flexibility, which allowed them to locally adapt their foraging strategies (intraspecific a dagger(1) = 0.70-0.77). Mean Delta(1) from all interspecific pairwise comparisons was negatively correlated with the number of carnivore species with a parts per thousand yen10 detections (r -0.76, p = 0.02). Our results suggest that temporal segregation is likely to play an important role in facilitating mesocarnivore coexistence, especially with increasing community complexity, where most species' activity peaks were asynchronous. These results contribute to understanding the dynamics and behavioural strategies of coexisting mesocarnivores, crucial for forecasting the possible outcomes of conservation or management actions.