Fruit resource provisioning for avian frugivores: the overlooked side of effectiveness in seed dispersal mutualisms

1. Mutualistic interactions between frugivorous birds and fleshy fruited plants are key processes for both natural plant regeneration and the maintenance of birds relying on fruit resources. However, seed dispersal effectiveness (SDE) has been frequently studied only from the plant’s perspective, i.e. the contribution of animals to plant fitness.

2. Using a sample of Atlantic rainforest avian frugivores, this study presents a first comparative, empirical study of fruit effectiveness as a nutritional food resource for seed dispersing birds through the use of Resource-Provisioning Effectiveness (RPE) models. RPE is the product of the amount of fruits a frugivore can consume (quantity component) and the quality of the ingesta in terms of energy and nutrients obtained (quality component).

3. Our results show wide variation in Resource-Provisioning Effectiveness among fleshy-fruited plant species. Energy-rich fruits consistently show a smaller quantity component, while energetically-po...