Successful frugivory interactions recovery 53 years after the reintroduction of the ariel toucan <i>Ramphastos ariel</i> in the Atlantic forest

The loss of ecological interactions due to defaunation affects ecosystems worldwide. As a solution, reintroductions are highlighted as key strategies for restoring ecological interactions and the functionality of defaunated ecosystems. However, quantitative studies assessing the success of reintroductions through interaction recovery remain scarce and are often conducted on recent reintroductions, focusing on short‐term outcomes. Here, we evaluate the recovery of frugivory 53 years after the reintroduction of Ramphastos ariel , a key seed disperser, in Tijuca National Park, Rio de Janeiro, Brazil, using an interaction credits (number of interactions that can be restored after a reintroduction) approach: the contrast between expected interactions (based on a literature review) and field‐observed interactions (feeding bouts method). Additionally, we incorporate a functional approach by categorizing dispersed seed size as small (&lt; 6 mm), medium (&gt; 6 mm and ≤ 12 mm), or large (&gt; 12 mm), since toucans can consume and disperse medium‐ and large‐seeded species, an essential function in defaunated ecosystems that have lost large dispersers. From the literature, we identified 101 potential interactions for R. ariel in Tijuca National Park and observed that 76% of these interactions occurred during one year of feeding bout observations. Specifically, we recorded 63% recovery for small‐seeded species, 88% for medium‐seeded species, and 89% for large‐seeded species. Our findings demonstrate the long‐term success of this reintroduction in restoring frugivory interactions and emphasize the importance of reintroduction efforts for ecological restoration. Additionally, we highlight the role of toucans as key species that interact with and potentially disperse medium‐ and large‐seeded plants in defaunated environments.