Exploring for Plants Conserving the Cockpit Country of Jamaica

Palau is home to the rarest, most endangered species of Ponapea. Known only from the Rock Islands, Ponapea palauensis inhabits moist, sheltered pockets among the limestone hills.

Ponapea palauensis, with most of its leaves clipped by cockatoos.

The exotic Sulphur-crested Cockatoo (Cacatua galerita) is a threat to Ponapea palauensis.

We found Ponapea palauensis in three sites, two of which were known populations that had been recorded within the past decade. The third was a new record for the species, but we only found a single juvenile plant. We explored two other known locations based on information that is over 50 years old, along with five other sites that had similar habitats. We did not find Ponapea in any of those locations. As we explored the Rock Islands, we were struck by the rarity of Ponapea palauensis relative to the other Rock Island endemic palm Hydriastele palauensis.

We observed considerable damage to the leaves of Ponapea palauensis in one site. The petioles (leaf stalks) had been clipped, and most palms had just a few leaves remaining in the crown. One palm had been killed recently, and its heart (bud) had been cut away. The damage appeared to have been caused by Sulfur-crested Cockatoos (Cacatua galerita), which are reported to feed on the hearts of Ponapea. Introduced from Australia decades ago, the cockatoos are increasing in numbers and appear to be a serious threat. We saw and heard many of them as we explored the Rock Islands.

Following the ranking criteria established by the World Conservation Union (IUCN), Ponapea palauensis is critically endangered. Its geographic range is tiny and fragmented, and the quality of its habitat is declining as the cockatoo population increases. It appears to be disappearing quickly, based on its absence from some previously recorded localities.