Data for: Effects of floral trait dissimilarity and flower density on pollinator-mediated interactions at different spatial scales

Conducted in nine coastal dune communities, the study assesses how floral trait dissimilarity affects pollinator sharing and how the co-flowering environment—floral dissimilarity, conspecific flower density, and heterospecific flower density—impacts pollination outcomes. Key metrics include flower visitation rates, conspecific pollen reception, and the proportion of pollen tubes. The study also investigates whether these effects vary at the plot and site scales.MethodsField sampling and flower densityPlant communities were surveyed at nine sites along a 205 km coastal stretch. Each site was sampled over three randomized days during the rainy season (September–November 2016). Within each site, ten 20 m² plots were established, recording flowering species identity, plant counts, and open flower numbers. Conspecific and heterospecific flower densities were estimated at both the plot (20 m²) and site scale (200 m²).Floral trait dissimilarityFloral traits—including corolla diameter, tube opening, and flower length—were measured in 1–5 flowers per plant from at least five plants per species. Floral symmetry and clustering were also recorded. Floral reflectance spectra (300–700 nm) were measured using a spectrophotometer to model color perception by Hymenoptera, Diptera, and Lepidoptera. Floral trait dissimilarity between species pairs was estimated using Gower’s dissimilarity index, and functional distinctiveness was calculated using an abundance-weighted index.Pollinator observations and pollinator sharingPollinator observations were conducted in each plot for three 5-minute periods (15 min total per plot per day). Only visits involving contact with reproductive structures were recorded. Pollinators were identified to species or morphospecies, and unidentified specimens were collected for later identification. Pollinator visitation rate was calculated as visits per flower per 15 minutes. Pollinator sharing was estimated using Pianka’s niche overlap index, considering both pollinator identity and visitation frequency.Pollen receipt and pollination successTo assess pollen receipt and pollination success, one style per plant was collected from senesced flowers at the end of the day and stored in FAA solution. Styles were processed using NaOH softening and aniline blue staining, and pollen grains and pollen tubes were counted under a fluorescent microscope. Pollen tube production was used as a proxy for pollination success, and all data were relativized to account for species-specific differences.