Abstract: What type of ecosystems more vuinerabie than the others in herms of inpact of invasive species? It is one of the focuses of modern species invasion ecology. Our survey on the invasive plants on 8 islands in northeastern water of Hong Kong(114°15'~114°27'E, 22°30'~22°34'N) was carried out recently. The results shown that the islands(including Island Sai Ap Chau, Island Ap Lo Chun and Island Ap Chau) with calcium-rich soil might be more invasible than other islands (including Island Lam Shuen Pai, Island Fu Wong Chau, Island Ngo Mei Chau, Island Wong Wan Chau) with low calcium soil. Although there are may more species of invasive plants in Island Kap O, the abundance of exotic plants is low and did not cause significant harm to the natural vegetation. Based on comparison of the invasive plants and island area, human disturbance and soil component, the results presented herewith on the relstionship between calcium and the fact that limestone, saline, beach, calcic soil that widely distributed in temperate zone and arid soil formed in Mediterranean Sea Climate was easily invaded by the invasive plants.

Key words: biological invasion, calcium-rich ecosystems, invasibility, invasive plants