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 ForestFocus on Indonesia: Page 4 Fig trees are among the most characteristic trees of Indonesia and other rainforests and are keystone species for wildlife. They are threatened by forest clearance and by loss of their seed dispersers. Some 800 species of fig trees are found in tropical rainforests around the world. On Borneo alone, there are 140 species, 13 of which are endemic (Yates 1992). Among the tallest trees in these forests, they may attain a height of 150 feet. Strangler figs grow on the trunks of other trees, which they gradually kill by encircling them. All fig trees are dependent on wasps less than an inch long for pollination. (See "Borneo's Strangler Fig Trees," by Tim Laman in National Geographic, April 1997, which illustrates this pollination process in detail.)
A wide variety of birds and mammals feed on the abundant fig fruits, but few species actually disperse the seeds. Figs contain chemical compounds that have a laxative effect on the wildlife that eat them, a reproductive strategy designed to release seeds over a wide area. Animals as small as ants and as large as wild pigs, gibbons, and deer feed on the fruit (Laman 1997). Figs exist in such variety in unlogged, primary tropical forests that one species is always fruiting, supplying life-giving food to wildlife (Laman 1997). Hornbills may be more important than any other species in dispersing fig seeds because, rather than eating a portion of the fruit only, they eat the entire fruit, which is full of tiny fertile seeds, and then fly long distances, spreading the seeds in defecations. One ornithologist observed fruiting fig trees in Borneo with as many as 50 hornbills of eight species feeding together (Yates 1992).
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