Chapter 8: Human Environment Interactions: The Tropical And The Subtropical Region

This chapter explores the relationship between humans and their environment in two distinct geographical regions: the tropical region, exemplified by the Amazon Basin, and the subtropical region, represented by the Ganga-Brahmaputra Basin. While people in different parts of the world may look different and have unique cultures, they share the same basic needs for food, clothing, and shelter. Their lifestyles, however, are heavily shaped by the natural environment they inhabit. Early in their lives, people living close to nature learn to care for it and utilize its resources, such as catching fish or collecting materials from forests.

Life In The Amazon Basin

The Amazon Basin is the largest river basin in the world, located in South America. The Amazon River and its numerous smaller rivers, called tributaries, drain a vast area that includes most of Brazil, and parts of Peru, Bolivia, Ecuador, Colombia, and Venezuela. The region is situated very close to the equator, stretching between 10°N and 10°S latitude, which is why it is also known as the equatorial region.

Climate

The Amazon Basin experiences a classic hot and wet equatorial climate throughout the year. The key characteristics are:

• High Temperatures: Days and nights are almost equally hot, with very little variation.
• High Humidity: The air is constantly filled with moisture, making the skin feel sticky.
• Daily Rainfall: It rains almost every day, often in the afternoon, with heavy downpours that occur without much warning.

Rainforests

The constant heat and heavy rainfall support the growth of extremely dense forests, known as tropical rainforests. These forests are so thick that the leaves and branches of the trees form a continuous "roof" or canopy, which prevents most sunlight from reaching the ground. This leaves the forest floor dark, damp, and ideal for shade-tolerant plants like orchids and bromeliads (which grow on other plants as parasites).

The rainforest is incredibly rich in fauna (animal life):

• Birds: Exotic birds like toucans and hummingbirds with brilliantly coloured feathers and large bills are common.
• Mammals: Animals such as monkeys, sloths, and ant-eating tapirs thrive here.
• Reptiles and Amphibians: The jungles are home to various snakes like the anaconda and boa constrictor, as well as crocodiles and thousands of insect species.
• Aquatic Life: The rivers are teeming with fish, including the infamous flesh-eating Piranha fish.

People Of The Rainforests

The indigenous people of the rainforest have adapted their lives to the forest environment. While men are traditionally responsible for hunting and fishing, women manage the agriculture, which forms the backbone of their food supply.

• Agriculture: They practice a method known as "slash and burn" agriculture. A small patch of forest is cleared by cutting down trees and burning them. The ash adds nutrients to the soil, and crops are grown for a few years. Once the soil loses its fertility, the plot is abandoned, and a new one is cleared. The staple food is manioc (also called cassava), a root vegetable similar to a potato. They also grow tapioca, pineapple, and sweet potato, and cash crops like coffee, maize, and cocoa.
• Housing: Some families live in thatched houses shaped like beehives. Others live in large, apartment-like communal houses with steeply slanting roofs, called "Maloca".
• Changing Lifestyles: Life in the Amazon is changing rapidly. The construction of the Trans-Amazon Highway in 1970 opened up remote parts of the forest to development. This has led to the displacement of indigenous populations and the large-scale destruction of the biologically diverse rainforests, causing problems like soil erosion and turning lush forests into barren landscapes.

Life In The Ganga-Brahmaputra Basin

The Ganga-Brahmaputra basin is formed by the tributaries of the two major rivers, the Ganga and the Brahmaputra, in the Indian subcontinent. It is located in the sub-tropical region, between 10°N and 30°N latitudes. The basin includes the Ganga and Brahmaputra plains, the foothills of the Himalayas, and the Sundarbans delta.

Geography and Climate

The basin has a varied topography, from steep mountain slopes to flat alluvial plains. The climate is dominated by the monsoon, which brings heavy rains from mid-June to mid-September. The summers are typically hot and the winters are cool.

Population and Agriculture

The environment heavily influences where people live. The flat, fertile plains are densely populated because they are ideal for agriculture and human settlement, whereas the mountainous areas are sparsely populated. Agriculture is the main occupation.

• Crops: The primary crop is paddy (rice), which requires abundant water. Other important crops include wheat, maize, millets, and gram. Cash crops like sugarcane and jute are also widely grown.
• Plantations: Tea is grown in plantations in West Bengal and Assam. Silk is produced through sericulture (cultivation of silkworms) in parts of Bihar and Assam.
• Terrace Farming: In the hills, where slopes are gentle, farmers practice terrace farming. They cut flat steps into the slopes to create surfaces for growing crops and to prevent rapid water runoff and soil erosion.

Vegetation and Wildlife

The vegetation varies with the landscape. The plains have tropical deciduous trees like teak, sal, and peepal. The delta area is covered with mangrove forests (the Sundarbans), while the mountains have coniferous trees like pine and deodar.

The basin is rich in wildlife, including elephants, tigers, deer, and monkeys. The Brahmaputra plain is famous for the one-horned rhinoceros. The delta is home to the Bengal tiger and crocodiles. The rivers are rich in aquatic life, including the endangered Gangetic dolphin, locally called Susu, whose presence indicates a healthy river ecosystem.

Towns, Cities, and Pollution

The fertile plains support several large towns and cities, such as Allahabad, Kanpur, Varanasi, Lucknow, Patna, and Kolkata. A major environmental issue is the pollution of the rivers, as untreated wastewater from these urban centers and industries is often discharged directly into them. Government initiatives like the "Swachh Bharat Mission" and the "Namami Gange Programme" have been launched to address these pollution issues.

Transport and Tourism

All four modes of transport—roadways, railways, waterways, and airways—are well-developed in the basin's plain areas. Kolkata, on the River Hooghly, is a major inland port. The region is also a major hub for tourism, with attractions like the Taj Mahal, Buddhist stupas, wildlife sanctuaries like Kaziranga and Manas, and places of distinct tribal culture in Arunachal Pradesh.