Can Wildlife Survive In The Rainforest Biome
When Surrounded By Smaller Land Islands?

Terrestrial Islands: Breaking Up The Rainforest Biome

By Rick Gregory

Charles Darwin and Alfred Russel Wallace made the first famous forays to the Galapagos Islands and Malay Archipelago to study the biology of tropic islands.

Now islands are popping up on the mainlands of every continent.

The global rainforest biome is breaking up into small patches of primary forests, isolated mountain habitats and other fragmented landscapes that are all too common.

In the past two hundred years, researchers have shown us how animals adapt and die out in isolated ecosystems.

Cut off from larger populations and left with limited resources for survival, the rate of extinction increases with every new highway or agricultural plantation that separates species into smaller and smaller jungle habitats. In effect, human activities have created terrestrial islands amid a sea of disturbed land; and the consequences for these isolated landlocked habitats will not be all to different from those islands surrounded by seawater.

Primate species diversity is a unique and fascinating aspect of mammals on Borneo Island. Among the menagerie are long-limbed gibbons, tiny bug-eyed tarsiers, big-nosed proboscis monkeys and the “man of the forest” or the orang-utan. All of these species are endemic to the rainforest biome of Borneo. But orang-utan habitat is dwindling.

The only great ape in Asia may not survive into the next century, at least not in the wild.

Logging continues to eat away at precious freshwater swamp and hill forests, only to be replaced by a stagnant sea of oil palm plantations. Some plantation owners hire hunters to shoot-to-kill these large, endangered primates if found nibbling on oil palm saplings. And periodic fires in peat lands cause damage to forests and create havoc and death for wildlife.

For the orang-utans in Borneo the rainforest biome is getting smaller, its food scarcer and the risk of local primate extinction increases with each new logging permit. Several attempts are being made to delay its pending demise, including the translocation of animals to wildlife refuges and reserves. But it remains to be seen if these animal conservation measure will provide large enough land areas for orang-utans to thrive.

Other researchers are studying the adaptability of orang-utans to exist in restricted habitats adjacent to plantations. If only the humans would cooperate, maybe it’s possible for our primate cousins to hazard a go into these disturbed land seas.

Similar scenarios are found for rhinos' and tigers' habitats. These larger rainforest mammal species require more land to maintain viable populations. But again the encroachment of agriculture and development activities renders smaller and smaller parcels of land to save for wildlife concerns. Without sufficient forest size, animals tend to become rare and that can eventually lead to animal extinction.

Conservationists are keenly aware of the problems of limited space and are looking into ways to connect these fragmented landscapes. With the aim of creating larger areas, wildlife managers try to puzzle together the pieces formed by national parks, forest reserves, rivers and wildlife sanctuaries.

Biological corridors are just one approach taken to find slivers of forests or other ecosystem byways that will allow species to move from one area to another. In a terrestrial island context, this is an attempt to secure land bridges so that wild animal populations will not be cut off from critical habitats or restrict the flow of the gene pool to unhealthy levels.

From the global wanderings of two bearded British naturalists to the concept of biological passageways, the impact of the lessons of island biogeography on modern conservation theories and practices is as enormous as the oceans surrounding tropic isles.

The entire planet is shrinking into a scattered mass of isolated land and water domains, and only a return to the study of islands in the rainforest biome will help us sort out what will hang on and what will be nonexistent in the future.

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Read Part I: Tropic Islands: Earth's Evolutionary Guards

Read Part II: Charles Darwin and Alfred Russel Wallace

Read Part III: Islands of Evolution

Go to Jungle Essays

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