A marine subsidy reshapes the ecology of a large terrestrial carnivore

Efforts to restore wildlife populations are increasing worldwide, yet many of these initiatives take place amidst significant ecological change. In altered ecosystems with novel species compositions, returning wildlife may alter their behaviours and interactions with other species. In Patagonia, the extirpation of terrestrial predators following European colonization, including the puma, facilitated the establishment of Magellanic penguin colonies along Argentina's coast. Recently, the creation of a national park in coastal Patagonia has fostered the recovery of pumas and resulted in an unexpected predator-prey relationship between pumas and penguins. Using a suite of animal movement metrics and generalized spatial mark-resight models, we tested how access to penguins affects puma behaviour and abundance. Consistent with the resource dispersion hypothesis, pumas responded to the availability and abundance of penguins by increasing their site fidelity when penguins were present but ranging more widely when the penguins migrated out of the park. This behavioural adaptation led to frequent encounters among pumas, suggesting greater social tolerance. Further, the park now supports the highest density of pumas recorded to date. Our work adds to a rapidly growing body of literature suggesting that the restoration of large carnivores in novel ecosystems can lead to novel interactions that transform their behaviours.