The Pelong Rocks are a small group of rocky islets at the mouth of Brunei Bay, on the NW coast of Borneo. Brunei Bay has a coastline shared by 4 separate Bornean states, the Malaysian states of Sabah and Sarawak the Malaysian Federal Territory of Labuan and the independent Sultanate of Brunei Darussalam. See map below.
The island of Borneo is surrounded by hundreds of tiny rocky islets with a unique ecology.
Rocky islets without vegetation often host breeding terns during the calm sea season (March to July) including Bridled Terns, Roseate Terns and Black-naped Terns. When a tern colony establishes, Reef Egrets may also breed at the same time so that they can predate the young terns. Terns prefer small rocky islets to breed because they are usually free from rats and monitor lizards. The Pelong rocks also host a substantial colony of Tomb Bats which presumably fly to the Brunei mainland to hunt for insects.
Larger islets are usually dominated by large strangling figs, primarily Ficus drupacea, Ficus virens and Ficus microcarpa. See these posts.
The fig seeds are brought by nomadic pigeons including, Pied Imperial, Grey Imperial Pigeon and White-throated Pigeon.
Once the fig trees are established they may be used for roosting by 3 species of Frigate birds (Lesser, Greater and Christmas Island) which breed in the seas around northern Australia and fish around the coast of Borneo when they are not breeding. Frigate birds bring the sticky seeds of Pisonia grandis which often competes for space with the fig trees.
The photos below of the Pelong Rocks show both fig trees and smaller Pisonia grandis trees (recognized by the yellowish leaves).The plants and their dispersers and pollinators that live on these islands must be tough enough to survive extreme winds, brackish water, and long droughts.
Each island is slightly different. For example islands surrounded by shallow coral reefs often have sandy beaches used for nesting by Green, Loggerhead and Hawksbilled sea turtles.
This record of Ficus superba is north of the recorded range. See map. However, because of the unique pollination system of figs which can only be pollinated by obligate species of fig wasps it can be predicted that the Ficus superba trees on the Pelong Rocks must be within fig wasp flight distance of other Ficus superba fig trees. It would be interesting to find out where these Ficus superba fig trees are located.
Thanks to Joremy Tony, Bruneian ecologist for photos and information.
