Inluded here are the Fiji Islands (such as Viti Levu and Vanua Levu), Samoa Islands, Tonga Islands, Horn Islands, Rotuma Islands, Uvea Island and Niue Island.

Fijian Summit Scrub

Scrub covers the summits of various islands including Ta’u and Tutuila in Samoa and Tafahi in northern Tonga. In Ta’u its presence seems to relate to the fact that forest was destroyed by relatively recent hurricanes. The dominant taxa include the endemic shrub Freycinetia storckii (Flagellariaceae), tree ferns (Cyathea) and terrestrial ferns such as Blechnum vulcanicum and Dicksonia brackenridgei. A similar type of vegetation occurs on Tafahi, but this appears to be more of a climax community. The dominant shrubs here are Geniostoma rupestre, Maoutia australis and the endemic Cyrtandra samoensis (Gesneraceae). On Tutuila the situation is slightly different in that all the shrubby vegetation is confined to the summits of ‘trachyte plugs’ (old volcanic cores). Here trees such as the endemic Astronidium pickeringii (Melastomataceae), Erythrospermum acuminatissimum (Flacourtiaceae), Pandanus reineckei (Pandanaceae), Psychotria insularum (Rubiaceae) and Syzygium brevifolia (Myrtaceae) are found in a tangle of ferns, shrubs and climbers. Ground flora in most of these scrub communities seems to be largely dominated by ferns such as Dicranopteris linearis and Dipteris conjugata.

Fijian Volcanic Scrub

Relatively recent lava flows are found on various islands including Niuafo’ou, Sauai’i and several small islands in Tonga. On Savai’i a series of eruptions in which volcanic material reached the coast occurred in 1760 and between 1905-1911. The vegetation that colonized these areas is still largely confined to cracks and crevices. Dominant trees include Fagraea berteroana, Glochidion ramiflorum and the endemic Ayrtera brackenridgei (family?). In more upland areas at elevations of about 1500 m species composition changes to one largely dominated by the endemic Coprosma strigulosa (Rubiaceae), Spiraeanthemum samoense (Cononiaceae) and Vaccinium whitmeei (Ericaceae). At ground level two native ferns, Davallia solida and Nephrolepis hirsutula are common, while on Niuafo’ou the ancient pteridophyte Psilotum nudum can be found in similar situations. However, these volcanic areas are far from uniform and in places there are ash plains virtually devoid of shrubs and mainly dominated by the grass Imperata conferta.

References

Ash, J. 1992. Vegetation Ecology of Fiji: Past, Present, and Future Perspectives. Pacific Sciences, 2: 111-127.

Gardger, R. O. 1997. New and noteworthy plants from Fiji. New Zealand Journal of Botany, 35: 487-492.

Garnock-Jones, P. J. 1978. Plant communities on Lakeba and southern Vanua Balavu, Lau group, Fiji. Royal Society of New Zealand Bulletin, 17: 95-117.

Kirkpatrick, J. B. & Hassall, D. C. 1985.  The vegetation and flora along an altitudinal transect through tropical forest at Mount Korobaba, Fiji. New Zealand Journal of Botany, 23: 33-46.

Mueller-Dombois, D. & Fosberg, F. R. 1998. Vegetation of the Tropical Pacific Islands. Springer.

Smith, A. C. 1951. The Vegetation and Flora of Fiji. Scientific Monthly, 73: 3-15.

Smith, A. C. 1954. Botanical studies in Fiji. Smithsonian Institute Report for 1954, 305-315.

Smith, A. C. 1955. Phanerogam genera with distributions terminating in Fiji. Journal of the Arnold Arboretum, 36: 273-292.

Smith, A. C. 1979. Flora Vitiensis Nova. A New Flora of Fiji. Vol. 1. Lawai, Kauai, Hawaii.

Uhe, G. 1974. The composition of the plant communities inhabiting the recent volcanic ejecta of Nuiafo’ou Tonga. Tropical Ecology, 15: 126-139.

Whistler, W. A. 1980. The vegetation of Eastern Samoa. Allertonia, 2: 45-174.

Whistler, W. A. 1983. Vegetation and flora of the Aleipata Islands, Western Tonga. Pacific Science, 37: 227-249.

Whistler, W. A. 1983. Vegetation of Samoa and Tonga. Pacific Science, 46: 159-178.