Aspectos reprodutivos de uma comunidade de Bromeliaceae em um fragmento urbano de Floresta Atlântica do Sudeste do Brasil

Abstract

Bromeliaceae is considered the fourth family of Angiosperms with the largest species richness of the Atlantic domain. In this biome, acts as one of the main families responsible for providing and maintaining food resources throughout the year for a diverse fauna of pollinators, especially hummingbirds. Despite the high ecological importance, there is still little knowledge about many aspects of reproductive biology of most species of bromeliads. In this context, this paper is structured in two chapters, where the studies were conducted in an Atlantic Forest remnant in the city of Juiz de Fora (MG), southeastern Brazil. Chapter I aimed to characterize the phenological pattern of breeding and investigate aspects of floral biology and pollination of nine species of Bromeliaceae. The sequential flowering of the species in the community and flowering asynchrony among individuals within the population, not only ensure the availability of food resources to flower visitors throughout the year, but also suggest to be strategies to avoid inter and intraspecific competition for pollinators. Pollen was the main floral resource offered and nectar was not produced by only two species. Nine species of pollinators were recorded, four of hummingbirds, one bat, three of Lepidoptera and one hymenopteran, where the hummingbird Phaethornis pretrei seems to act as "pollinatorkey" within the community studied. Chapter II aimed to investigate the breeding systems and reproductive success of Portea petropolitana and Billbergia horrida, two endemic species of the Brazilian Atlantic Forest whose natural populations are being threatened by human activity, especially by habitat fragmentation. Both species are allogamous and autoincompatible, and dependent of pollinators for fruit and seed formation, and in the study area, have a high rate of fruit set under natural conditions. Portea petropolitana is effectively pollinated by hummingbirds. B. horrida, on the other hand, has a generalist pollination system involving bats, moths and hummingbirds. In summary, this study extended the knowledge about aspects of the reproductive biology of Bromeliaceae, and generated important data to support the development of strategies for the conservation of natural habitats affected by fragmentation processes and the species studied.