Isolated from continental life, evolution on islands can take its own course, allowing many unique lineages and high levels of endemism. In some sites, the age of endemic species varies significantly from the average, a phenomenon thought to be associated with the origin of the island. Recent endemism is associated with oceanic islands, i.e. islands formed de novo, whereas ancient endemism is linked to continental islands, i.e. islands formed by fragmentation.
Focusing on monocots, this study sought to identify islands with significant endemic flora of more recent, ancient or mixed lineages, and to investigate factors contributing to these patterns. Using GBIF-mediated plant occurrences representing 15,964 species found on 4,306 islands, the authors calculated a measure of phylogenetic endemism and identified 142 islands as being either recent, ancient or mixed—with a subset of 42 islands being 'super-endemic', an extreme case of the last category.
The islands identified—irreplaceable for uniqueness and evolutionary history—can help guide biodiversity conservation. While distributed across the entire world, most are present at low latitudes. In addition, the authors found that habitat availability and climate stability were the most important environmental factors contributing to endemism.