Recursos florais em áreas agrícolas: um caminho para conciliar a conservação da diversidade de abelhas com produção de alimentos

Abstract

We depend on biodiversity and the ecosystem services it provides to maintain our well-being. Pollinators and pollination are an example of this dependence; through the pollination of crops and wild plants, pollinators such as bees increase crop productivity globally and ensure the reproduction of native flora. However, agricultural expansion and intensification cause habitat loss and reduce the availability of floral resources that bees need to survive and persist. To reconcile food production with biodiversity conservation, it is necessary to minimize the impact of agricultural production on pollinator diversity. Considering that management practices that increase pollinator diversity are a promising approach to biodiversity conservation in agricultural areas, we structured this thesis into two chapters: 1) We conducted a systematic review of the effect of floral enrichment on bee diversity globally, and 2) We evaluated whether local availability of floral resources and management strategies in coffee crops affect bee diversity. We found 148 studies in the review, and the topic began to be developed recently (2000), mainly in temperate countries and monoculture areas. We also found that there are few articles on the effect of floral enrichment for each type of crop found, that the works are carried out with newly established floral enrichments are short-lived and carried out during or outside the crop flowering. Therefore, future studies need to cover a greater diversity of climatic regions, agricultural production systems, and types of crops, as these variables can influence the results and, consequently, the choice of the most appropriate enrichment technique for bee conservation in different regions and production systems. We also need data to understand the dynamics between mature enrichments and bee diversity because this data can positively influence the result of floral enrichment in the bee assembly. And samplings that are conducted both during and outside the main crop flowering are necessary to understand the temporal complementarity relationship of floral resources in agricultural areas. In the second article, we showed that resource availability positively affects bee visitation rate. The Halictini bees and Plebeia spp. genus were positively influenced, and Apis mellifera (Linnaeus, 1758) bees were negatively influenced by the transition to organic farming. Therefore, the availability of flowering plants and the transition to organic management contributed positively to bee visitation rate and diversity, mainly native ones. We showed that perennial crops can offer resources beyond the crop flowering itself, and management measures that allow spontaneous plant flowering are effective actions to increase bee presence, which should result in more sustainability in cultivated areas. Considering the analyzed results, we conclude that 1) more research on floral enrichment is essential, considering some factors missing in the literature, such as studies in different climatic conditions, in different types of crops, in areas with mature floral enrichment, long-term studies, and collections conducted both during flowering and before or after. And that 2) the transition to organic farming and management measures to allow spontaneous plant flowering - such as spacing the time of removal of spontaneous plants (mowing) or reducing/replacing pesticides - are efficient measures to promote sustainability in agricultural areas.