Several plant species in the Neotropics bear large, fleshy fruits that suggest adaptation to endozoochorous seed dispersal by large vertebrates. Many of these plants, however, occur in areas where large vertebrates are no longer present, consequently, their seeds are dispersed by pulp consumers; small vertebrates that only ingest the pulp reward because they are uncapable of swallowing the fruits whole. Few studies have examined the role of these pulp consumers on the regeneration of large-fruited/seeded plants. Here, we assessed seed disperser effectiveness (SDE) and context-dependence in SDE of pulp consumers of Pouteria splendens, a large-seeded tree, considered a tropical relict in Mediterranean Chile. We found that P. splendens fruits are consumed by six species of non-flying vertebrates; four of which act as dispersers with very low effectiveness. Low SDE resulted from the quantitative, rather than the qualitative component, specifically from low frugivore visitation rates. Most seeds remained under P. splendens trees, either from being dispersed there or because they were not dispersed at all. However, both emergence and establishment probabilities were higher under conspecific plants than in other habitats, suggesting no negative density-dependent effects on P. splendens recruitment. Although the absence of more effective dispersers does not seem to affect local recruitment probabilities, it results in the absence of long-distance dispersal services, further isolating the remnant P. splendens populations. Finally, although pulp consumers are dispersers of P. splendens with very low effectiveness, the key functional role of these species is to remove the fleshy pulp from the seed as its presence significantly reduces germination probability.

Seedling emergenceSeedling emergence in experimental stations set up in three habitats (Under Pouteria, open interspaces, and dry riverbeds) during 2015 and 2016Seedling_emergence.csvTotal number of visits and dispersed seeds per disperserTotal number of visits of each of the six frugivores that consume P. splendens, and total number of seeds dispersed during 2638 hours of video monitoring.visits_dispersed.csvTotal number of visits and dispersed seeds during 2015Total number of visits of each of the six frugivores that consume P. splendens, and total number of seeds dispersed during 2015 (473 h of video monitoring)visits_dispersed_2015.csvTotal number of visits and dispersed seeds during 2016Total number of visits of each of the six frugivores that consume P. splendens, and total number of seeds dispersed during 2016 (2165 hours of video monitoring)visits_dispersed_2016.csv