Linking structure and functioning in plant-frugivore interactions: importance of core frugivores and equivalence in their seed dispersal

ROMÁN A. RUGGERA; PEDRO G. BLENDINGER; MARÍA D. GOMEZ

Drakensberg

Simposio; 6th International symposium-workshop on Frugivores and Seed Dispersal; 2015

Multi-species mutualisms are thought to have a core of few species that disproportionally affect to the remaining species in a network. Yet, the relative influence of core and peripheral species has not been properly tested, and the existence of geographical gradients in biodiversity has challenged the understanding on how reciprocal adaptations between frugivores and fruits could emerge. We propose that core species from different sites could be equivalent in the seed dispersal provided, which imply that cores could act as a unique selective force for fruit traits in a regional scale. We specifically ask: 1) Do core species affect partners more strongly than peripheral species? 2) Are core birds from different sites equivalent in the quantitative component of seed dispersal effectiveness (QC) provided? We monitored bird-fruit interactions in 10 sites of Yungas forest, NW Argentina. We recorded 3579 interactions with 69 fleshy-fruited plant species; 8 core bird species dispersed a larger seed number and seeds from more species than 46 peripheral bird species. Core birds had a higher QC than peripheral birds when consuming fruits of shrubs (Fobs=7.64; p=0.005), subcanopy (Fobs=19.1; p