Tropical urban areas support highly diverse plant-pollinator interactions: An assessment from Brazil

Abstract

Urban areas contribute to conservation of pollinators, but we lack assessments from the most biodiverse tropical regions in the world. We synthesized studies on urban plant-pollinator interactions across Brazil, compiling 86 studies conducted in urban green spaces that reported 2678 interactions for 519 plant and 337 animal species. We evaluated the spatio-temporal distribution of the data, effects of sampling and conducted interaction network analyses. Most studies were conducted after the 2000s, in highly urbanized Atlantic Forest areas, with overrepresentation of large public institution areas. Most studies are of difficult access to the international audience as they were published in Portuguese and in local journals. Around 60% of the plants associated to pollinators are native while only three floral visitor species were categorized as exotic. Bees were the most diverse group and had the highest number of interacting plants, but avian and mammal pollinators were also found in urban areas. Hence, many native pollinators benefit from urban floral resources. Sampling effort and method impacted the number of interaction partners recovered, indicating the need for complementary and better planned sampling protocols. Mostly herbs and shrubs acted as network hubs across Brazilian urban landscapes, so these life forms are important to support pollinators and should be promoted for this purpose. We advocate for better standardized and planned research on urban plant-pollination interactions in diverse tropical countries, in order to accomplish a truly global effort on conservation of pollinators in urban areas.