The flora of the Chagos Archipelago: a conservation checklist of native and introduced plant species

The Chagos Archipelago is a remote group of low-lying coral islands in the central Indian Ocean whose terrestrial flora has received relatively little sustained attention compared with its marine ecosystems. Botanical knowledge of the islands is scattered across historical expeditions, herbarium specimens, grey literature, and more recent ad hoc observations, with no fully standardised, openly accessible synthesis of occurrence data. Much of the existing information is taxonomically outdated, inconsistently georeferenced, or difficult to reconcile with modern biodiversity data standards, limiting its utility for ecological analysis, conservation planning, and long-term monitoring. At the same time, increasing availability of digitised herbarium records, citizen-science observations, and global biodiversity infrastructures provides an opportunity to consolidate these disparate sources into a coherent, curated dataset. Establishing a transparent and reproducible baseline for the vascular plant flora of the Chagos Archipelago is therefore an essential step towards improving understanding of species composition, biogeographic affinities, and patterns of persistence and introduction in this isolated island system.

This paper presents a curated, standardised checklist for the vascular plants of the Chagos Archipelago. All records have been taxonomically harmonised using current nomenclature and structured according to Darwin Core terms to ensure interoperability with global biodiversity infrastructures. The dataset documents both native and introduced taxa, includes explicit treatment of cultivation and casual occurrences, and records temporal patterns of observation that were previously unavailable in a unified form.