Abstract:

To find out the main plant community types of uninhabited islands in the nearshore Xiamen, in mid-to-late October 2017, we recorded 360 vascular plant species, including 78 trees, 109 small trees or shrubs, 23 vines and 150 herbs. We also found 49 invasive alien species, 10 of which have been identified as the most serious invasive. Compositional analysis showed that vegetation in these 12 uninhabited islands were of tropical and sub-tropical types. Consistent with the subtropical geography of these islands, vegetation mainly consisted of pan-tropical species and its variants. Generally, the islands had similar species composition. Herbaceous plants dominated the flora of these islands. Power and logarithm functions best described the species-area relationships of island vascular plants. Area had the largest effect on species richness of these islands followed by other spatial parameters such as the ratio of shoreline length, elevation, and perimeter area. Habitat diversity and island edge affected similarity of vascular plant species among different islands. Except for Wuyu Isle, we did not find evidence for small island effects in these surveys.

Key words: uninhabited islands, flora, spatial features, species similarity, invasive alien species