A quantitative framework for identifying umbrella taxa in the supralittoral zone of wave-exposed sandy beaches

Sandy beach biodiversity is under increasing pressure from anthropogenic stressors across the ocean-land interface, creating an urgent need for cost-effective conservation tools. Umbrella taxa can serve as proxies for co-occurring biodiversity in spatial conservation planning and guide habitat-based conservation actions that benefit broader communities. However, quantitative frameworks for identifying and validating umbrella approaches remain limited. We developed a framework combining co-occurrence potential, rarity, and sensitivity to human modification to assess the umbrella potential of 71 taxa across 30 wave-exposed beach sectors in southeastern Brazil. The resulting portfolio integrated resident arthropods, particularly Cicindelidae and Staphylinidae, with sea turtle nests, shorebirds, and taxa associated with adjacent habitats, notably wrack deposits and coastal vegetation. Umbrella combinations consistently outperformed random sets of equivalent size in taxonomic and spatial coverage. Pairs of selected umbrella taxa achieved high biodiversity representation across relatively few beach sectors. Our results provide a reproducible framework for identifying regional umbrella portfolios, guiding spatial prioritization and potential monitoring of habitat-based conservation outcomes.