Ecology and genetics of Carpoxylon macrospermum H Wendl & Drude (Arecaceae), an endangered palm from Vanuatu

The documented population of the rare and endangered endemic Vanuatu palm, Carpoxylon macrospermum H. Wendl. & Drude (Arecaceae), comprises 154 reproductively mature individuals, and progressively larger numbers of associated juveniles and seedlings, scattered throughout nine islands of the Vanuatu archipelago. Of the total, only 32 mature individuals occur naturally on three islands - Aneityum, Futuna and Tanna - in the south of the archipelago. The remainder of the population are cultivated, primarily as single individuals, in village situations where the palm has varying degrees of traditional importance. The species is most often a subcanopy to emergent element in rainforest where it forms scattered small colonies. Preferred habitat appears to be moist lowland forest on high-fertility soils, in microclimates where drainage may be impeded or where high soil moisture levels are permanently maintained. Genetic variation within the population was determined by random amplified polymorphic DNA (RAPD) analysis. Only at two sites - Lown'ock and Yeruareng on Tanna - of the 26 sampled in total (of which 19 provided usable embryos), was there any significant variation detected. This result indicates that whatever variation there is will be found in the natural populations and that most cultivated plants are apparently derived from a limited number of trees. For practical conservation purposes and to maintain maximum genetic variation within the existing and future populations, propagating materials will need to be collected from these two sites plus any one of the other sites. In reference to population sustainability, the number of mature individuals in the known population is extremely small, and therefore the species is presently under considerable threat from land clearance, habitat degradation and genetic erosion induced by isolation and declining numbers. Copyright (C) 1996 Elsevier Science Limited