Are pulp consumers effective seed dispersers? Tests with a large‐seeded tropical relict tree. (4th October 2018)

• Record Type: Journal Article
• Authors: Peña‐Egaña, Mara; Loayza, Andrea P.; Squeo, Francisco A.
• Is Part Of: Biotropica. Volume 50:Number 6(2018)
• Page Start: 898
• Page End: 907
• Publication Date: 2018-10-04
• Subjects: Context‐dependence -- intra‐specific facilitation -- Pouteria splendens -- Sapotaceae -- SDE -- seed dispersal; Biotic communities -- Tropics -- Periodicals; Applied ecology -- Tropics -- Periodicals; Biology -- Tropics -- Periodicals; 577.80913
• DOI: 10.1111/btp.12604
• Languages: English
• ISSNs: 0006-3606

Abstract

Abstract: Several plant species in the Neotropics bear large, fleshy fruits that suggest adaptation to endozoochorous seed dispersal by large vertebrates. Many of these plants 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 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, further isolating the remnant P. splendens populations. Finally, although pulp consumers have very low disperser effectiveness, the key functional role of these species is to remove the fleshy pulp from P. splendens ' seed as its presence significantly reduces germination probability.