About 55% of the island is covered in dense
rain forest, mostly on the windward southern and western sides of the island and in the central highlands. The eastern shore and the northern and southern tips of the island are covered in grassland or reed, with some plantations of introduced
Caribbean pine (
Pinus caribaea). Ridge thicket, a low-growing
cloud forest with a tree canopy of 7 meters or lower, grows along the central ridge and extends as low as 200 meters elevation on windy ridges on the island's southern and western slopes. Ridge thicket is characterised by abundant large ferns including the
tree ferns
Cyathea spp. and
Leptopteris wilkesiana, the climbing vines
Freycinetia spp., and limited-range species like the palm
Physokentia petiolata, which only occurs on Gau and the highlands of Viti Levu. The Fiji petrel's nesting habitat on the island contributes to its national significance as outlined in Fiji's Biodiversity Strategy and Action Plan. A marine research facility was established on Naviavia beach on the western coast of Gau in 2005 by the UK-based
non-governmental organization Frontier, commissioned by Dr. Joeli Veitayaki of the
University of South Pacific, a native of Malawai on the eastern coast. ==Notable people==