The global distribution of human-visible flower color diversity

Abstract

The spectacular diversity of flower colors is among the most widely appreciated features of the natural world. For over a century, biologists and naturalists have speculated about whether human-visible flower color diversity shifts predictably across ecological systems worldwide. Yet challenges in measuring color across the vast diversity of flowering plants have limited global tests of these patterns. Using a computer-vision enabled analysis of community science data across 64,000 species, we modeled the major global features of human-visible flower color. We find a robust latitudinal gradient in color diversity after standardizing the number of species sampled from each flora, with flower colors occurring in more even proportions toward the equator. Modeling flower color alongside climate and pollination strategy reveals associations with both biotic and abiotic factors. These findings provide a global basis for testing how ecological and evolutionary processes shape the relative representation of floral phenotypes, beyond differences in species richness.