Included here is the Ryukyu Archipelago situated between Kyushu and Japan, and comprising Okinawa, Ishigaki, Iriomote, Tokuno-Shima, and the Amami and Tokara islands.

Ryukyuan Beach and Dune Vegetation

Several beach and sand dune vegetation zones have been recognised in the Ryukyu Archipelago.

Beach Vegetation
The sandy shores include Glehania littoralis and Ixeris repens in the pioneer zone, with Cassytha filiformis, Ipmoea pes-caprae ssp. brasilense, Spinifex littoreus, Thuarea involuta and Vitex rotundifolia in the more stable zones.

Vigna marina- Ipomoea pes-caprae Pioneer Zone
Mainly confined to the higher parts of the beach this vegetation zone is often reached by the sea and during typhoons maybe completely washed away. Other species may include Calystegia soldanella, Glehnia littoralis, Panicum repens, Raphanus sativus var. hortensis, Spinifex littoralis and Thuarea involuta.

Zoysia sinica Pioneer Zone
This vegetation usually occurs in areas where the Ipomoea pes-caprae community has been disturbed. It includes most of the species mentioned for the Vigna marina- Ipomoea pes-caprae zone. Other associated species include Artemisia capillaries, Cirsium spinosum and Wedelia prostrate.

Glehnia littoralis-Spinifex littoralis Fixed Dune Zone
This vegetation develops on stabilised sand where some humus has accumulated. The physiognomy is mainly determined by the stiff grass Spinifex littoralis which can reach heights of 70 cm. Most of the species mentioned for the Vigna marina- Ipomoea pes-caprae and Zoysia sinica pioneer zones can also be found here. Others include Clerodendrum inerme, Lepturus repens and Maytenus diversifolius.

References

Miyawaki, A. & Suzuki, K. 1993. Dry Costal Ecosystems of Japan. In: Ecosystems of the World. 2B. Dry Coastal Ecosystems. Africa, America, and Oceana. Ed. Eddy van der Maarel. Elsevier.

Numata, M. (ed). 1974. The flora and vegetation of Japan. Elsevier Scientific Publishing Company.

Numata, M., Miyawaki, A. & Itow,  D. 1972. Natural and semi-natural vegetation in Japan. Blumea, 20: 435-481.