Nectar availability and Interactions with Bird Pollinators in Grevillea banksii R. Br. (Proteaceae) in a Restinga Ecosystem in Southeastern Brazil

Abstract

The mutualistic relationship between plants and their pollinators may influence species’ spatial distribution, richness, and abundance. We assessed the nectar availability and interaction with pollinators in Grevillea banksii (Proteaceae), an alien plant in Brazil. Our objectives were to study the floral biology and the pollination system and identify the pollinators in a G. banksii population in a Restinga ecosystem (sand-coastal-plain) in southeastern Brazil. We described the behavioral parameters of the pollinator-plant interaction and determined how the pollinators contribute to reproduction. Floral biology was analyzed by taking morphometric measurements of the flowers and determining the distribution of their structures. The reproductive system was assessed via different pollination treatments (open pollination, self-pollination, manual selfpollination, manual cross-pollination). The pollinators were identified and their behaviors were assessed by focal observation. Flower morphometrics showed compatibility between the mean calyx length and the beak length of the flower-visiting hummingbirds. All the pollination types tested were efficient, and we identified eight bird species (Chionomesa fimbriata, Eupetomena macroura, Chlorestes notata, Polytmus guainumbi, Florisuga fusca, Coereba flaveola, Cyanerpes cyaneus and Dacnis cayana) that visit G. banksii in the study area. The results show a positive interaction between pollinators and plants, with offers of resources, pollination, and pollen dispersal.