Chapter 5 - Natural Vegetation and Wildlife
Question and Answers
Question 1: Define
a) Natural Vegetation
b) Biome
Answer:
a) Natural vegetation refers to a plant community, which has grown naturally without human aid and has been left undisturbed by humans for a long time. This is termed as a virgin vegetation. Thus, cultivated crops and fruits, orchards form part of vegetation but not natural vegetation.
b) A very large ecosystem on the land having distinct types of vegetation and animal life is called biome.
Question 2: What are endemic and exotic species?
Answer: The virgin vegetation, which are purely Indian are known as endemic or indigenous species but those which have come from outside India are termed as exotic plants.
Question 3: “India is rich in flora and fauna”. Justify the statement.
Answer:
• Our country India is one of the 12 mega bio-diversity countries of the world. With about 47,000 plant species India occupies tenth place in the world and fourth in Asia in plant diversity.
• There are about 15,000 flowering plants in India, which account for 6 per cent in the world’s total number of flowering plants.
• The country has many non-flowering plants, such as ferns, algae and fungi. India also has approximately 90,000 species of animals, as well as, a rich variety of fish in its fresh and marine waters.
Question 4: What factors are responsible for distribution of plants and animals in India?
Answer:
Relief
• Land
→ Land affects the natural vegetation directly and indirectly.
→ The fertile level is generally devoted to agriculture.
→ The undulating and rough terrains are areas where grassland and woodlands develop and give shelter to a variety of wildlife.
• Soil
→ Different types of soils provide basis for different types of vegetation.
→ The sandy soils of the desert support cactus and thorny bushes, while wet, marshy, deltaic soils support mangroves and deltaic vegetation.
→ The hill slopes with some depth of soil have conical trees.
Climate
• Temperature
→ On the slopes of the Himalayas and the hills of the Peninsula above the height of 915 metres, the fall in the temperature affects the types of vegetation and its growth, and changes it from tropical to subtropical temperate and alpine vegetation.
• Photoperiod (Sunlight)
→ The variation in duration of sunlight at different places is due to differences in latitude, altitude, season and duration of the day. Due to longer duration of sunlight, trees grow faster in summer.
• Precipitation
→ In India, almost the entire rainfall is brought in by the advancing southwest monsoon (June to September) and retreating northeast monsoons. Areas of heavy rainfall have more dense vegetation as compared to areas of less rainfall.
Question 5: Why are forests important for human being?
Answer:
• Forests are renewable resources and play a major role in enhancing the quality of environment. They modify local climate, control soil erosion, regulate stream flow, support a variety of industries, provide livelihood for many communities and offer panoramic or scenic view for recreation.
• They control wind force and temperature and cause rains.
• They provide humus to the soil and shelter to the wildlife.
Question 6: Describe briefly about the different types of vegetation.
Answer:
• Tropical Evergreen Forests
→ These forests are restricted to heavy rainfall areas of the Western Ghats and the island groups of Lakshadweep, Andaman and Nicobar, upper parts of Assam and Tamil Nadu coast.
→ They are at their best in areas having more than 200 cm of rainfall with a short dry season.
→ The trees reach great heights up to 60 metres or even above.
→ Some of the commercially important trees of this forest are ebony, mahogany, rosewood, rubber and cinchona.
→ The common animals found in these forests are elephant, monkey, lemur and deer. One-horned rhinoceroses are found in the jungles of Assam and West Bengal.
• Tropical Deciduous Forests
→ These are the most widespread forests of India. They are also called the monsoon forests and spread over the region receiving rainfall between 200 cm and 70 cm. Trees of this forest type shed their leaves for about six to eight weeks in dry summer.
→ On the basis of the availability of water, these forests are further divided into moist (100-200 cm) and dry deciduous (70-100 cm).
→ Teak, bamboos, sal, shisham, sandalwood, khair, kusum, arjun and mulberry are commercially important species.
→ In these forests, lions, pigs, deer, and elephants are main animals. Besides a variety of bird, snakes and lizards are found here.
• The Thorn Forests and Scrubs
→ In regions with less than 70 cm of rainfall, the natural vegetation consists of thorny trees and bushes.
→ This type of vegetation is found in the north-western part of the country, including semi-arid areas of Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Uttar Pradesh and Haryana.
→ Acacias, palms, euphorbias and cacti are the main plant species.
→ Trees are scattered and have long roots penetrating deep into the soil in order to get moisture.
→ In these forests, the common animals are rats, mice, rabbits, fox, wolf, tiger, lion, wild ass, horses and camels.
• Montane Forests
→ In mountainous areas, the decrease in temperature with increasing altitude leads to the corresponding change in natural vegetation.
→ The wet temperate type of forests are found between a height of 1000 and 2000 metres.
→ Evergreen broad-leaf trees, such as oaks and chestnuts predominate.
→ Between 1500 and 3000 metres, temperate forests containing coniferous trees, like pine, deodar, silver fir, spruce and cedar, are found.
→ At high altitudes more than 3,600 metres above the sea level, temperate forests and grasslands give way to the Alpine vegetation. Silver fir, junipers, pines and birches are the common trees of these forests.
→ The common animals found in these forests are Kashmir stag, spotted dear, wild sheep, jack rabbit, Tibetan antelope, yak, snow leopard, squirrels, Shaggy horn wild ibex, bear and rare red panda, sheep and goats with thick hair.
• Mangrove Forests
→ The mangrove tidal forests are found in the areas of coasts influenced by tides.
→ Dense mangroves are the common varieties with roots of the plants submerged under water.
→ The deltas of the Ganga, the Mahanadi, the Krishna, the Godavari and the Kaveri are covered by such vegetation.
→ In the Ganga- Brahmaputra delta, sundari trees are found, which provide durable hard timber.
→ Palm, coconut, keora, agar, etc., also grow in some parts of the delta.
→ Royal Bengal Tiger is the famous animal in these forests. Turtles, crocodiles, gharials and snakes are also found in these forests.
Question 7: “India has rich fauna”. Explain.
Answer:
→ India is also rich in its fauna. It has approximately 90000 animal species. The country has about 2,000 species of birds. They constitute 13% of the world’s total.
→ There are 2,546 species of fish, which account for nearly 12% of the world’s stock. It also shares between 5 and 8 per cent of the world’s amphibians, reptiles and mammals.
→ The elephants are the most majestic animals among the mammals. They are found in the hot wet forests of Assam, Karnataka and Kerala.
→ One-horned rhinoceroses are the other animals, which live in swampy and marshy lands of Assam and West Bengal.
→ Arid areas of the Rann of Kachchh and the Thar Desert are the habitat for wild ass and camels respectively.
Question 8: What are the steps taken by the government of India to protect the flora and fauna of the country?
Answer:
→ The main causes for this major threat to nature are hunting by greedy hunters for commercial purposes.
→ Pollution due to chemical and industrial waste, acid deposits, introduction of alien species and reckless cutting of the forests to bring land under cultivation and habitation, are also responsible for the imbalance.
→ To protect the flora and fauna of the country, the government has taken many steps.
• Eighteen biosphere reserves have been set up in the country to protect flora and fauna. Ten out of these, the Sundarbans Nanda Devi, the Gulf of Mannar, the Nilgiri, Nokrek, Great Nicobar, Manas, Simlipal, Pachmarhi and Achanakmar-Amarkantak have been included in the world network of biosphere reserves.
• Financial and technical assistance is provided to many botanical gardens by the government since 1992.
• Project Tiger, Project Rhino, Project Great Indian Bustard and many other eco-developmental projects have been introduced.
• 101 National Parks, 553 Wildlife sanctuaries and Zoological gardens are set up to take care of natural heritage.
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