Introduction to the Rainforests of Southeast Asia

The tropical rainforests of Southeast Asia are a part of the earth's oldest existing tropical ecosystems. They span acorss Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam. They are also thought to be the most biologically diverse ecosystems as their biological diversity and richness is unparalleled by that of the Brazilian Amazon and African tropical rainforests. Despite this fact, Southeast Asia is losing its forest coverage faster than any other tropical region in the world; it is estimated that 10 years from now, the primary forests of Southeast Asia will be completely destroyed. The climate of the Southeast Asian rainforest is in a constant state of heat and humidity with an average yearly temperature of about 80 degrees Fahrenheit. The east coast of the Southeast Asian islands gets heavy rain but for the most part, the humidity and climate remains consistent throughout the seasons with the coldest month of the year only reaching temperatures up to 18 degrees Celsius. All seasons are essentially hot and humid, with very little temperature variation. Known for their rich biodiversity, the tropical rainforests of Southeast Asia harbor thousands of different tree species (as many as 200 in one hectacre alone). There are also plenty of endangered plant and animal species in the Southeast Asian rainforests including the Bengal Tiger, the Dawn Bat, the Orangutan, the Proboscis Monkey, the Silvery Gibbon, the Slender Loris, and the Sumatran Rhinoceros. Maintaining the ecological well-being of this ecosystem is vital to the survival of the many plant and animal species that it harbors. (http://www.blueplanetbiomes.org)

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Maps of Southeast Asian Tropical Rainforest Coverage

The tropical rainforests of Southeast Asia span across several Southeast Asian countries ranging from India and Burma in the west to Malaysia and the islands of Java and Borneo in the east.

Southeast Asian Tropical Rainforest Map

Source: Rainforests.mongabay.com

 Southeast Asian Forest Cover Map (Detailed)

Source: European Commission Institute for Sustainability 2003

Rainforest Images (Then and Now)

Before:

Historically, the rainforests of Southeast Asia have always been lush with green vegetation, and teeming sites of biodiversity.

Source: flawedthinkerthinks.blogspot.com

 Source: readtodo.info

 Source: blueplanetbiomes.org

Source: blueplanetbiomes.org
 
Source: blueplanetbiomes.org

After:
Now, however, the rainforests of Southeast Asia have suffered the effects of incessant deforestation. Deforestation and logging have created devastation in many regions of Southeast Asia's tropical forests.

Borneo's degradation over time is a prime example of the long-term effects of deforestation.

Source: http://earthtrends.wri.org

Source: http://blogs.ei.columbia.edu

Source: commercialpressuresonland.org

A Brief History of the Southeast Asian Rainforest

Since the Pleistocene Epoch (dating 70 million years back on the earth's geologic time scale),the Southeast Asian rainforests existed on Earth.Over millions of years, however, the tropical rainforests of Southeast Asia have undergone a multitude of changes. Nearly 8000 years ago, almost the entire region of Southeast Asia was covered by forestry. Currently, only about one half of the initial forest-covered land remains, and most of the countries in this region are experiencing rapid deforestation. Southeast Asia contains the world's third largest concentration of tropical forests, and it is experiencing deforestation at a rate higher than almost anywhere else on Earth. It estimated that by 2100, this region will lose up to three quarters of its initial forest coverage and up to 42% of its current biodiversity.(Trends in Ecology 2004)

The rainforests of Southeast Asia attest to an incredibly high level of biodiversity. The reason for this is because millions of years ago, while the rest of the world's climate underwent extreme cooling and warming cycles, the climate of Southeast Asia remained relatively stable because of the ecosystem's proximity to the equator and water. The water from the surrounding oceans provided the rainforests with plenty of moisture in the form of rain. The increased levels of precipitation (as well as periods of warming and cooling) caused the sea levels to fluctuate and subsequently episodically mold mountains into geographically isolated islands; these set of conditions turned out to be ideal for speciation. During the Pleistocene glacial episodes, unique wildlife reservoirs, known as "forest refugia", survived in small patches of forest. Additionally, during the last Ice Age, Malaysia and the islands of Borneo, Sumatra and Java all belonged to the same singular landmass. Once the glaciers melted and the sea levels rose, however, these "wildlife reservoirs" were isolated and cut off from each other, subsequently forcing species to develop their own evolutionary paths in response to their local environment. The isolation of the islands enabled the extreme diversification of species by driving the animals to adapt to their varying locales. The unique geological history of Southeast Asia, places the rainforests of this region at the top of world's list of the most biologically diverse ecosystems (in terms of species richness and endemism). (Trends in Ecology 2004)

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Human Impacts on the Southeast Asian Rainforests

The rainforests of Southeast Asia are under constant threat from detrimental human impact/involvement. Most notoriously, the region's forests are endangered and threatened by conversion to agriculture, logging (both legal and illegal), and encroaching oil palm plantations. The human impacts on the rainforests in Southeast Asia have driven many endemic tropical plant and animal species to the brink of endangerment and even extinction. This grave loss of biodiversity has disturbed the equilibrium of the species endemic to the tropical rainforest ecosystem which has subsequently resulted in a biological catastrophe. Humans have also promoted widespread deforestation in the tropical rainforests of Southeast Asia by advocating and supporting industries (such as that of timber, palm oil, and agriculture) that are directly involved in the mass, commercial removal of tropical trees.

Figure 1: Factors Driving Deforestation in Southeast Asia

Source: Mongabay.com

 Human driven deforestation in Southeast Asia has produced impacts on its rich and unique biodiversity, with Singapore being the most intensively affected country. The most immediate impact of human logging activities is the destruction of the unique multi-layered tropical forest canopy. Logging in both Borneo and Malaysia has adversely impacted the species richness of trees; seedlings in logged locations were discovered to be especially nutrient poor, implying that logged forests require a longer duration of time to recover their initial richness of species. Logging in the tropical forests of Southeast Asia has posed a particular problem because of the high density of commercially valuable tree species that this region contains. Logging and timber production have been major sources of deforestation in the lowland forests where the high proportion of desirable timber species is prevalent, make these regions ideally susceptible to the devastating effects of the logging industry. Illegal logging has also produced a "biological catastrophe" in Indonesia by negatively affecting thousands of endemic plant and animal species, and subsequently disturbing the natural balance the biological equilibrium that keeps a rainforest stable and healthy. Legal and illegal logging has prompted the loss of a multitude of "forest refugia" (or wildlife reservoirs) in the Southeast Asian rainforests, which are crucial to the replenishing of tropical plant and animal species. The timber industry has also catalyzed the fragmentation of habitats; in the future this fragmentation will promote the loss of multiple species whose roles (which include the provision of essential ecological services such as seed dispersal and pollination) are critical to survival of the Southeast Asian tropical rainforests. Once these crucial species are driven into complete extinction, the rainforest ecosystem of Southeast Asia will collapse and cease to exist. (Catalyst Magazine 2004)

Figure 2: Population extinctions in Southeast Asia and Singapore. Green and blue bars represent recorded and inferred extinctions in Singapore, respectively. Yellow and red bars represent minimum and maximum projected extinctions in Southeast Asia respectively. Source: Trends in Ecology and Evolution, Sodhi, Koh, Brook, Ng.

Palm-oil, a popular ingredient utilized in commercial food products, has rapidly become a global commodity and a source of destruction for the rainforests of Southeast Asia. In the last decade alone the production of this commodity has more than doubled and the land area harvested for palm oil (in the rainforests of Southeast Asia) has tripled. Palm oil plantations not only account for the rapid rate of deforestation and forest degradation in Southeast Asia, but they also represent a disproportionately large source of global warming emissions. These emissions arise from the copious amounts of carbon dioxide and methane released into the atmosphere from the decaying soil beneath the established plantations. The increase in human involvement in the rainforests through the advancement of palm oil plantations, along with the expansion of logging, agriculture, and urbanization, has produced devastating effects on the tropical rainforests of Southeast Asia by facilitating a decline in species richness and biodiversity, rampant deforestation, and an overall deterioration of the ecological well-being of the rainforest ecosystem. (Trends in Ecology 2004)

Figure 3: Future expansion of palm oil in Indonesia.

 

Source: Vital Forest Graphics