A matter of time not of co-occurrence: temporal partitioning facilitates coexistence between coyotes (Canis latrans) and gray foxes (Urocyon cinereoargenteus) in temperate forests of Mexico

Sympatric species reduce competitive interactions by segregating their ecological niche as a strategy that promotes coexistence. The main dimensions in which niche differentiation occurs are spatial, trophic, and temporal axes. Thus, describing the spatiotemporal patterns of sympatric species help us better grasp how species coexist. In Mexico, coyotes (Canis latrans) and gray foxes (Urocyon cinereoargenteus) are sympatric and widely distributed, and information about their temporal and spatiotemporal interactions is still needed to explain their coexistence throughout their distribution. The evaluation of the ecological niche in temperate forests where both species coexist has shown high spatial and trophic overlap. Therefore, more pronounced segregation must occur in other niche dimensions, such as temporal and spatiotemporal axes, to maintain the coexistence between coyotes and gray foxes. As an approach to exploring the coexistence between these species in temperate forests, we pose the following question: Is there temporal or spatiotemporal segregation between sympatric coyotes and gray foxes? We hypothesized that both species maintain coexistence due to differences in their daily activity patterns (temporal segregation) and the presence of avoidance behaviors at the spatiotemporal level (spatiotemporal segregation), thereby reducing agonistic interactions. We aimed to evaluate indicators of niche segregation through two approaches: (i) temporal niche partitioning, measuring the overlap of the daily activity patterns and activity levels; and (ii) spatiotemporal niche partitioning, through temporal co-occurrence analysis and time to encounter analysis. In 2018, we used a camera-trap array (n = 43) to evaluate spatiotemporal interactions of coyotes and gray foxes in temperate forests of northern Mexico. We found that coyotes exhibited a diurnal daily activity pattern, whereas gray foxes were nocturnal, showing low overlap between daily activity patterns. Temporal co-occurrence and time to encounter analysis showed that coyotes and gray foxes occurred independently of each other. Therefore, we demonstrated that the spatiotemporal interactions between both species is a result of random species associations. In conclusion, here we provide evidence that ecological segregation occurred in the temporal niche and not in the spatiotemporal niche of the species. Thus, the temporal niche segregation represents one of the ecological strategies that facilitates the coexistence between coyotes and gray foxes and therefore promotes their sympatry in the temperate forests of northern Mexico.