title: The potential indirect effects among plants via shared hummingbird pollinators are structured by phenotypic similarity.
abstract: Plant species within communities may overlap in pollinators' use and influence visitation patterns of shared pollinators, potentially engaging in indirect interactions (e.g., facilitation or competition). While several studies have explored the mechanisms regulating insect-pollination networks, there is a lack of studies on bird-pollination systems, particularly in species-rich tropical areas. Here, we evaluated if phenotypic similarity, resource availability (floral abundance), evolutionary relatedness and flowering phenology affect the potential for indirect effects via shared pollinators in hummingbird-pollinated plant species within four communities in the Brazilian Atlantic forest. Among the evaluated factors, phenotypic similarity (corolla length and anther height) was the most important variable, while resource availability (floral abundance) had a secondary importance. On the other hand, evolutionary relatedness and flowering phenology were less important, which altogether highlights the relevance of convergent evolution and that the contribution of a plant to the diet of the pollinators of another plant is independent of the level of temporal overlap in flowering in this tropical system. Interestingly, our findings contrast with results from multiple insect-pollinated plant communities, mostly from temperate regions, in which floral abundance was the most important driver, followed by evolutionary relatedness and phenotypic similarity. We propose that these contrasting results are due to high level of specialization inherent to tropical hummingbird-pollination systems. Moreover, our results demonstrated that factors defining linkage rules of plant-hummingbird networks also determinate plant-plant potential indirect effects. Future studies are needed to test if these findings can be generalized to other highly specialized systems. Overall, our results have important implications for the understanding of ecological processes due resource sharing in mutualistic systems.
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, 13083-970, Campinas, SP, Brazil.|Programa de Pós-Graduação em Ecologia, Instituto de Biologia, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil.
authors.forename: Pedro Joaquim
authors.initials: PJ
authors.lastname: Bergamo
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, 13083-970, Campinas, SP, Brazil.|Instituto de Ciências da Natureza, Universidade Federal de Alfenas, 37130-001, Alfenas, MG, Brazil.
authors.forename: Marina
authors.initials: M
authors.lastname: Wolowski
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, 13083-970, Campinas, SP, Brazil.
authors.forename: Pietro Kiyoshi
authors.initials: PK
authors.lastname: Maruyama
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, 13083-970, Campinas, SP, Brazil.|Programa de Pós-Graduação em Ecologia, Instituto de Biologia, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil.|University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors.forename: Jeferson
authors.initials: J
authors.lastname: Vizentin-Bugoni
authors.affiliation: Departamento de Ecologia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, 70910-900, Brasília, DF, Brazil.|Center for Ecology, Evolution and Environmental Changes(CE3C), Faculdade de Ciencias da Universidade de Lisboa, 1749-016, Lisbon, Portugal.
authors.forename: Luísa G
authors.initials: LG
authors.lastname: Carvalheiro
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, 13083-970, Campinas, SP, Brazil.
authors.forename: Marlies
authors.initials: M
authors.lastname: Sazima
mesh_terms: D000818:Animals; D001717:Birds / Q000502:physiology*; D001938:Brazil; D035264:Flowers; D010944:Plants; D054817:Pollination
keywords: Atlantic forest; competition; ecological interactions; facilitation; floral traits; pollinator sharing; reproductive interference; tropical pollination networks