The NW end of Sipadan island is rich in strangling fig trees of two species (1) Ficus callophylla and (2) Ficus glandifera.
Ficus callophylla is an uncommon fig of primary forest in Borneo. In contrast Ficus glandifera is an extremely rare fig of coastal Borneo that originates from Sulawesi. However on Sipadan F. glandifera is more common than F. callophylla. On the surrounding islands of the Tun Sakaran Marine Park near the coastal town of Semporna in East Borneo both F. callophylla and F. glandifera are absent. On these islands where the little remaining forest is degraded the common large strangling figs are F. virens, Ficus microcarpa and Ficus drupacea.
This is the first of two articles examining the ecology of Ficus glandifera.
All photos by Chun Xing Wong of 1StopBorneo Wildlife
Ficus glandifera growing near the NW tip of Sipadan island. The host tree has died and this strangler fig is self supporting but the location of the original seed on the host can be seen to be about 6 m from the ground. Notice that this beach on the western side of Sipadan is being subject to relentless erosion which will eventually destroy the fig.
In this case the host for Ficus glandifera is a Terminalia catappa or Sea Almond (ketapang). Both host and strangler are falling into the sea due to coastal erosion of the western beaches of Sipadan and probably do not have long to live.
This Ficus glandifera strangler near the northern jetty on Sipadan is hosted by a Intsia bijuga bean tree.
Leaves of the Ipil Ipil (Intsia bijuga ) tree. Intsia bijuga is a typical large forest tree of island forest around Borneo but is now very rare as the timber is ideal for boat building.
Flowers of Intsia bijuga or Ipil Ipil (cockroaches in Malay)
The beans of Instia bijuga are oblong, hard, and flat (like a larg cockroach) and were once a common drift seed on the beaches of Borneo especially in areas of undisturbed coastal forest. Intsia wood is locally known as Merbau and is widely used for boat building and house construction in coastal areas. It is now rare to find large Instia bijuga trees on the islands around Borneo.
The orange oval shows both the area of old growth forest and Ficus glandifera presence on Pulau Sipadan. It appears that Ficus glandifera needs the large trees of old growth forest to survive.The satellite photos confirms what can be seen at ground level. The strong winds of the NW Monsoon (December to March each year) cause waves to wash away sand from the west coast which later accumulates on the expanding east and south coasts. Thus the preferred habitat of F. glandifera on Pulau Sipadan is shrinking year by year.