Efeitos indiretos mediados por polinizadores em comunidades de plantas

Author(s)

Pedro Joaquim Bergamo

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2020-03-27

Examining board members

Marlies Sazima; Marina Wolowski; Camila de Toledo Castanho; Isabela Galarda Varassin; Leandro Freitas; Thomas Michael Lewinsohn

• Advisor: Marlies Sazima

Abstract

Flowering plants often share pollinators, leading to pollinator-mediated indirect effects. Although several studies have evaluated pollinator-mediated effects between plant species pairs, it is still unclear how indirect effects determine ecological processes at the community-level. It is uncertain which ecological factors determine the direction of the pollinator-mediated indirect effects (from competition to facilitation) and how such effects influence patterns and processes in plant communities. In this context, assessments of density-dependence in pollination and the incorporation of fitness estimates may improve the understanding about how pollinator-mediated indirect effects act on plant communities. We evaluated pollinator-mediated indirect effects at the community-level by characterizing conspecific and heteroespecific density-dependence in pollination and its implications in coexistence (Chapter 1) and how such effects influence the structure and dynamics (Chapter 2) of a tropical highland grassland plant community. We also developed a theoretical and analytical framework using network theory to study pollinator-mediated indirect effects and applied it to a mediterranean dune plant community (Chapter 3) and to an ornithophilous flora of a tropical montane forest Park (Chapter 4). We found negative density-dependence (showing intraspecific competition for abundant plant species) and interspecific facilitation most for rare plant species in pollination of the highland grasslands, a combination that fosters coexistence in this community marked by low pollinator activity. Moreover, ecological factors such as specialization, floral display and pollinator functional group determined the direction of the density-dependence and interspecific indirect interactions. Otherwise, periods with high floral abundance and low functional diversity of reproductive traits were associated with high fitness in the highland grasslands. These structural community patterns highlight the prevalence of facilitation among species with similar reproductive traits. Nevertheless, we identified a predominance of interspecific competition in pollination influencing plant fitness in the mediterranean dunes and interspecific facilitation in pollination alleviating pollen limitation of the ornithophilous floral in the montane forest. The indirect effects were asymmetrical in these two communities: generalized and attractive plant species acted as the ones causing the indirect effects, whereas specialized and less attractive species as the ones receiving such effects. Thereby, we showed how pollinator-mediated indirect effects influence patterns and processes in plant communities. In summary, we provided evidence on how pollination is an important niche axis, mediating plant-plant interactions at the community-level (AU)

• FAPESP's process: 16/06434-0 - Plant-pollinator interactions in communities and the assembly of functional traits and of the reproductive success
• Grantee: Pedro Joaquim Bergamo
• Support Opportunities: Scholarships in Brazil - Doctorate