Format: ORAL

Victor H. D. Silva1, Ingrid N. Gomes1, Pietro K. Maruyama1

1- Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil

Urbanization is a major threat to pollination, due to the transformation of natural landscapes into urban matrices. Previous studies indicate that highly urbanized areas have a higher negative effect on pollinators and their interactions with flowers. However, most of this information comes from non-tropical regions, emphasizing the need for studies in the tropics. Here, we evaluated the impact of urbanization on the richness of pollinators, plants, and interactions in a large tropical metropolis, across twelve sampling points with varying levels of impervious surface.Over a one-year period, we conducted monthly visits to each of these points, sampling over 1 km transects. During these visits, we observed and recorded all flowering plants, as well as interactions with pollinators. Throughout the study, we recorded 7,603 plants-pollinators interactions, involving 234 plant and 217 pollinator species. Urbanization did not influence pollinator (pseudoR2= 0.154; p=0.151) and interaction richness; (pseudoR2= 0.083; p=0.311), but it negatively influenced plant richness (pseudoR2= 0.357; p = 0.0129). Analyzing seasonal variation, we observed that plant, pollinator, and interaction richness were significantly higher in the rainy season compared to the dry season (t = 3.69, W = 125, W = 127; p<0.001, respectively). The plant species most frequently visited included Sphagneticola trilobata, Tridax procumbens, Leucanthemum vulgare, and Psychotria carthagenensis. During the rainy season, Sphagneticola trilobata (a native species) emerged as the predominant resource for pollinators, while in the dry season, Tridax procumbens (non-native) took precedence. With the exception of Psychotria carthagenensis (Rubiaceae), all other frequently visited flowers belong to Asteraceae. These findings offer crucial insights into the impact of urbanization on biodiversity and ecosystem dynamics, with important implications for biodiversity conservation in tropical cities. Additionally, they underscore the substantial potential of Asteraceae plants and non-native species in supporting pollinators in urban areas.