Islands represent unique ecological niches as they are seperated from other land masses by water. Not all islands are the same, however, as the distance from an island to continents and neighboring islands affects the level of endemism and relatedness with land masses in the vicinity.
Taiwan is geologically active continental island formed 2-3 million years ago on a complex convergent boundary between four tectonic plates. In this study of Taiwanese flora, researchers used GBIF-mediated occurrences of all flowering plants in East and South Asia to categorize plants into either endemic or non-endemic, and to identify potential sources of the latter group.
Their work identified 847 endemic and 2428 non-endemic angiosperm species. Analysis of the Asian distribution of non-endemics revealed 34 terrestrial ecoregions, of which those tropical and subtropical play the most important role as sources of species richness in Taiwan.
Surprisingly, closeness was not the only factor, as a higher number of angiosperm species in Taiwan are shared with Papua New Guinea than the Philippines, the closest tropical island.