Palau's rare and threatened palm Ponapea palauensis (Arecaceae): Population density, distribution, and threat assessment

Abstract

Ponapea palauensis Kaneh., a palm endemic to the Palau archipelago in the western Caroline Islands, has previously been reported to be threatened and in decline due to predation by two species of introduced parrots, Cactua galerita Lath, and Eclectus roratus P. L. S. Mull., and potential predation by introduced rats. Here we assess its threatened status under the IUCN Red List Criteria and provide the first quantitative assessment of its population size. A complete distribution map is also provided establishing its total area of occupancy and maximum extent of occurrence. We find that the species qualifies for a minimum of Vulnerable status on the IUCN Red List, and it potentially qualifies for Critically Endangered status pending confirmation of a continuous population decline. Historical records of predation on the palms by parrots are consistent with current observations indicating that the species is threatened and in need of a management plan for conservation action and long-term monitoring of the stability of the extant population.