Danum Valley Conservation Area, Borneo, Malaysia Photograph by David Olson   Southeastern Asia: the Island of Borneo Tropical and Subtropical Moist Broadleaf Forests   44,600 square miles (115,600 square kilometers) -- about the size of Pennsylvania Relatively Stable/Intact

· Isolated Mountains
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
· More Photos

Isolated Mountains

If you visited these montane rain forests, you would feel as if you were on a mountaintop island surrounded by a sea of lowland forests and clouds. The isolation of the higher reaches of the ecoregion has produced a unique and diverse set of species. Because large tracts of these rain forests have still not been explored, it is likely that many species remain to be discovered.

Special Features

Located in the center of the island of Borneo, these montane forests are much cooler and moister than those in the lowlands. Rainfall is higher, and many forests also derive moisture from the clouds that envelop the high mountains of this island. Oak, chestnut, and Myrtaceae species can all be found in abundance here. As you move higher, leaves get smaller and trees shorter until the landscape transforms into an alpine meadow. Pitcher plants, rhododendrons, orchids, and moss species are especially diverse high in the mountains.

	Macaques are large, powerful monkeys--often weighing more than 30 pounds. They have a wider geographical range than any other kind of monkey or ape, ranging from western Europe and North Africa to the tropics of Southeast Asia to the snowy reaches of northern Japan.

Wild Side

Although their numbers decrease at higher altitudes, more than 150 species of mammals can be found here, including primates such as orangutans, gibbons, langurs, and macaques. Macaques, in particular, seem to roam lowland and montane regions in similar densities. Smaller mammals such as civets, tree shrews, squirrels, and rats fill these forests as well. Undisturbed areas can even support such large mammals as the endangered Sumatran rhinoceros. More than 250 species of birds also live here, including 26 near-endemic species and two endemics, the Hose’s broadbill and the black oriole.

Cause for Concern

Because of its isolation and rugged landscape, this ecoregion remains largely intact, with only about eight percent cleared or converted to agricultural uses. The ecoregion includes the largest protected block of rain forest in Borneo, the Kayan Mentarang Nature Reserve. But mining operations, large dams, high-altitude timber operations, and road building are all increasing threats to this ecoregion’s biodiversity.

For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.