Lorence, David H. and Wagner, Warren L. 2019. Flora of the Marquesas Islands. Volume 1: Lycophytes, ferns, and monocots. Kalaheo: National Tropical Botanical Garden.
The Marquesas Islands (French Polynesia) are a volcanic archipelago of 12 main islands, numerous islets, and exposed rocks situated in within the Polynesia-Micronesia biodiversity hotspot, an epicenter of the current global extinction crisis. The Marquesas are one of the most isolated groups of oceanic islands, located in the southeast Pacific Ocean between 7°50' – 10°35' S latitude and 138°20' – 140°30' W longitude and lying over 5,500 km from the west coast of Mexico and over 3,900 km southeast of Honolulu. With a total surface area of 1,065.5 km², the islands range in size from 0.2 to 339 km², in elevation from 1 to 1,276 m, and in age from 0.76–5.52 Ma. The native vascular flora comprises approximately 331 species including 100 ferns and lycophytes and 231 angiosperms, with 47.4% endemism. Floristic affinities are with the Society Islands, other Polynesian islands, the paleotropics, and to a lesser degree the Hawaiian Islands and the neotropics. Human colonization and the introduction of non-native animals and plants have severely impacted the low- to mid-elevation vegetation of the Marquesas. The island of Nuku Hiva is used to exemplify the various types of Marquesan vegetation and associated plant communities. Leeward areas below 300 m have relict patches of Sapindus-Xylosma dry forest with remnants of Dinebra grassland and Pisonia dry forest in the coastal regions. In leeward areas from 300 to 1,000 m anthropogenic grasslands of Miscanthus, Paspalum, and Melinus have been induced by fires and overgrazing. These grass dominated associations have largely replaced native, xerophytic shrublands of Malvaceae. Low- to mid-elevation (300–800 m) windward, montane sites harbor moist and wet forest associations of Hibiscus, Angiopteris, and Pandanus. Mid- to high-elevation (800–1,000 m) sites usually support moist or wet forests of Metrosideros, Weinmannia, Hernandia, and tree ferns (Alsophila, Sphaeropteris). The highest slopes and summits, at and above ca. 900–1,000 m, have cloud forest or summit wet shrubland communities. Based on extensive botanical field surveys, the conservation status of the native and endemic vascular plant species is discussed for each island, natural areas of high ecological and conservation value are proposed, and recommendations for conservation priorities are provided. Three new taxonomic combinations are made, all in the fern family Thelypteridaceae: Coryphopteris marquesensis (Lorence & K. R. Wood) Lorence & A. R. Sm., Pneumatopteris florencei (A. R. Sm. & Lorence) A. R. Sm. & Lorence, and Sphaerostephanos castaneus (A. R. Sm. & Lorence) A. R. Sm. & Lorence.
