Assessing interactions between coypus and capybaras in urban habitats: spatial and temporal overlap

Two competing species can coexist over time if they segregate along at least one key dimension of their ecological niche: space, time, or resources. Urban habitats influence these processes by homogenizing landscapes, reducing available niche space, and inducing behavioral adjustments that alter animals’ temporal activity, thereby affecting their capacity for segregation. In such contexts, coexistence may depend on subtle adaptations that minimize resource competition. This study examines spatio-temporal overlap between coypus ( Myocastor coypus ) and capybaras ( Hydrochoerus hydrochaeris ) inhabiting gated communities in the Metropolitan Area of Buenos Aires, Argentina. Our objectives were to: (1) assess spatial overlap and co-occurrence; (2) analyze overlap in daily activity patterns and their seasonal variation; and (3) evaluate simultaneous spatio-temporal co-occurrence and its seasonal dynamics. Results revealed a high degree of spatial and temporal overlap between coypus and capybaras, with both species showing greater tolerance to share space during warmer seasons, when food resources are more abundant. However, segregation emerged at the simultaneous spatio-temporal scale, mediated by differences in peak activity periods and likely related to mechanisms of direct encounter avoidance. This fine-scale segregation is consistent with the competitive exclusion principle and suggests that interference competition may occur when resources are limited, particularly in colder seasons. These findings highlight how urbanization constrains niche availability and promotes coexistence through behavioral and temporal adjustments, while also showing that interactions between both species may vary according to resource availability and seasonal conditions.