Seed dispersal mutualisms play a critical role in structuring plant and animal communities in tropical forests. The relatively aseasonal climatic conditions in tropical environments favor year-round primary production and a variety of phenological patterns. The continuous turnover and abundance of different fruit resources across time and space drive movements and feeding behavior of avian consumers. Yet, how this spatiotemporal complexity shapes the plasticity (i.e. ‘rewiring’) of species interactions in mutualistic communities remains poorly understood in seed dispersal systems. To investigate the consequences of seasonal change on the composition of local communities and their interaction patterns, we monitored local communities at six private farms in the central Dominican Republic continuously over a full annual period. Specifically, we quantified the local abundance of all avian species and fleshy fruits by surveying along transect grids at each 25-ha study site on 21 visits. We sampled the attendance and feeding interactions of frugivorous birds through focal observations of all plant taxa encountered with ripe fruits on each visit.
Results/Conclusions
We recorded 6,092 frugivory interactions involving 45 avian species and 48 plant species. Weighted centrality analysis showed that mutualistic dependence of the plant community was highly skewed toward a core set of four endemic birds. The composition of networks was strongly driven by the local abundance of resource and consumer taxa, which were highly heterogenous across the study region. Moreover, by explicitly accounting for the temporal changes in bird and fruit resource abundance at the local scale, we determined that the period over which birds and ripe fruits are present in the system correlated positively with the number of mutualist partners. Our results demonstrate the importance of phenology in determining species role within plant-frugivore networks and reveal new insights into the dynamic reassembly of plant-frugivore communities across seasons.