Island biodiversity is increasingly impacted by habitat loss and species invasions in the Anthropocene. Integrating classical island biogeography with functional ecology offers a framework to better understand species assembly and ecosystem functioning through trait-based analyses.

Functional island biogeography, which focuses on traits such as dispersal mode, life form, and resource-use strategies, remains constrained by the Raunkiaeran shortfall—the limited availability and coverage of trait data. Open-access databases (e.g., TRY, GBIF, GIFT) provide a foundation to address this limitation and enable large-scale comparative studies.

Preliminary assessment from multiple island systems demonstrate how species lists and functional traits can be integrated to assess island functional diversity across the globe. Other persistent challenges include data incompleteness, taxonomic bias, and inconsistent trait resolution. Addressing these gaps through improved data standardization and adherence to FAIR (Findable, Accessible, Interoperable, Reusable) principles is essential for advancing a predictive and globally relevant functional biogeography of island ecosystems.