Islands are key for protecting the world's plant endemism

Island Plant Species Distributions Contracted at the Cooler Edge Compared to Mainland

Continental islands have long been used as ecological models for understanding species assembly dynamics in isolated habitat fragments. But competition or colonisation constraints might be different to mainland populations, manifesting as expanded or contracted ranges across a geographic distribution of islands in comparison to a mainland population range. Here, we demonstrate that plants on coastal islands do not experience ecological release due to lack of competition, but rather a contracted range at the cool edge in a cross-continental dataset of 843 small coastal islands spanning contrasting environments fringing the Australian coast. We found the cool edge of species ranges across their distribution of small islands averaged 2.2°C warmer in mean annual temperature, or about 4-500 km nearer the equator. The tendency not to colonise islands at the cool edge suggests species may struggle to track their niche poleward as the climate shifts over fragments of habitat on the mainland.

Southern Islands Vascular Flora (SIVFLORA) dataset: A global plant database from Southern Ocean islands

The Southern Islands Vascular Flora (SIVFLORA) dataset is a globally significant, open-access resource that compiles essential biodiversity data on vascular plants from islands across the Southern Ocean. The SIVFLORA dataset was generated through five steps: study area delimitation, compiling the dataset, validating and harmonizing taxonomy, structuring dataset attributes, and establishing file format and open access. Covering major taxonomic divisions, SIVFLORA offers a comprehensive overview of plant occurrences, comprising 14,589 records representing 886 species, 95 families, and 42 orders. This dataset documents that 58.62% of the taxa are native, 9.61% are endemic, and 31.77% are alien species. The Falkland/Malvinas Archipelago, the most species-rich, contrast sharply with less diverse islands like the South Orkney Archipelago. SIVFLORA serves as a taxonomically harmonized, interoperable resource for investigating plant diversity patterns, ecosystem responses to climate change in extreme environments, island biogeography, endemism, and the effects of anthropogenic pressures on Southern Ocean flora.