Environments and People - Dragons and Tigers: A Geography of South, East and Southeast Asia - page 31

Figure 2-6
This is the always busy Chao Praya river in
Bangkok, Thailand. Photograph courtesy of
B. A. Weightman.

Brahmaputra. These water-deposited sediments, in con-
cert with extensive river networks and relatively flat
land, have helped make the Indo-Gangetic Plain one of
the most densely populated regions on Earth.
South of the Indo-Gangetic Plain rises the Central
Indian Plateau and the dissected Deccan Plateau. Cover-
ing most of peninsular India, the Deccan is bordered by
narrow coastal plains along the western Malabar and
eastern Coromandel coasts. The tear-shaped island of
Sri Lanka lies about 20 miles (32 km) across a narrow
strait to the southeast of the Coromandel coast.
Mainland Southeast Asia is a washboard of moun-
tains and fluvial (river-related) landforms. Mountain
ranges, with elevations as high as 18,000 feet (5,400 m),
are generally aligned in a north-to-south direction. One
exception is the S-shaped Annamite Cordillera that fol-
lows practically the entire coast of Vietnam from south-
ern China. Mountain chains are arranged closely in the
north with virtual slots of lowland in between. Further
south, the slots widen into V -shaped valleys and eventu-
ally into open plains, basins, and deltas.
Mountains have created cultural barriers for the in-
habitants of interstitial, riverine zones and they have en-
couraged ethno-linguistic diversity as each of hundreds
of different culture groups maintained its own way of life
in relative isolation from others for centuries.
Rivers are of paramount importance in mainland
Southeast Asia. The Ayeyarwady (Irrawaddy), Chao Praya,
Mekong, and Red River valleys have their headwaters on
the Tibetan Plateau. So tortuous is the surrounding
mountain terrain that the source of the Mekong was not

found until 1994. River valleys foster support of millions
of inhabitants and provide excellent sites for the growth
and development of major cities, including most capitals
(Figure 2-6).
Peninsular Southeast Asia extends 900 miles
(1,449 kmfr om the Gulf of Thailand to the island of
Singapore. The narrowest portion, the Isthmus of Kra, is
roughly 40 miles (64 km) across. It widens to the south
to form the Malay Peninsula.

ISLAND REALMS
South, East, and Southeast Asia are ringed by islands.
Some, such as Sri Lanka and Singapore, are politically in-
dependent states. Others are part of island chains called
archipelagoes Japan, the Philippines, and Indonesia are
all archipelagoes. Each comprises several large islands
and hundreds, or even thousands, of smaller ones. Japan
is dominated by the large island of Honshu, but there are
three other sizable islands (Hokkaido, Kyushu, and
Shikoku) and hundreds of lesser ones. The Philippines
incorporates more than 7,000 islands along with the
larger islands of Luzon and Mindanao. However, the
biggest is not necessarily the most important. For in-
stance, the Indonesian archipelago totals more than
17,000 islands, dominated in size by Sumatra, Sulawesi
(Celebes), and Kalimantan (Borneo). However, Indone-
sians and their political and economic centers are most
heavily concentrated on the much smaller island of Java.
New Guinea, the world' s second largest island
(after Greenland), is politically divided between