Plant-pollinator interactions in the cerrado: patterns and landscape effects

Abstract

Changes in vegetation cover and the intensification of human activities are among the main drivers of biodiversity loss in tropical ecosystems. the Cerrado, these transformations alter vegetation structure and floral resource availability, affecting plant-pollinator interaction dynamics and, consequently, the ecological mechanisms governing the structure, organization, and functioning of interaction networks that underpin plant reproduction and ecosystem stability. Despite recent advances, comprehensive syntheses of these interactions remain scarce, particularly those integrating functional and structural dimensions. In this thesis, I investigated how environmental and anthropogenic variation influence the diversity, structure, and functioning of plant-pollinator interactions in the Cerrado, using systematic review analyses, functional diversity metrics, and interaction beta-diversity. In the first chapter, based on a systematic review, I identified geographic, taxonomic, and functional knowledge gaps in plant-pollinator interactions, with records concentrated in few regions and species, reflecting a lack of information on certain floral traits and specific visitor groups. In the second chapter, I evaluated the relationship between functional diversity and modularity in a comprehensive metanetwork, showing that particular combinations of floral traits and visitor groups shape modules, and that central species play a disproportionate role in network cohesion and resilience. In the third chapter, I analyzed the interaction beta-diversity along a gradient of savanna landscapes in southern Minas Gerais and observed high dissimilarity among sites, as well as a trend toward structural homogenization in more human-modified environments. Together, the results demonstrate that environmental heterogeneity and human pressures strongly shape interaction networks in the Cerrado. While modularity and specialization confer local resilience, they also increase vulnerability to the loss of central species and to landscape simplification. I conclude that conserving plant-pollinator interactions in the Cerrado requires maintaining functional diversity and habitat heterogeneity, because the loss of specific functional combinations drives interaction reorganization and network structural homogenization, undermining the stability of pollination processes.