CBSE Class 9 Social Science Natural Vegetation And Wildlife Chapter Notes

NATURAL VEGETATION & WILDLIFE

India is one of the twelve 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 ass ferns, algae and fungi. India also has 89,000 species of animals as well as rich variety of fish in its fresh and marine waters.

Natural vegetation: Refers to a plant community which has grown naturally without human aid and has been left undisturbed by human for a long time. This is termed a virgin vegetation. thus, cultivated crops and fruits, orchards are a part of vegetation but not natural vegetation. India’s natural vegetation has undergone many changes due to several factors such as the growing demand for cultivated land, development of industries and mining, Urbanisation and over-grazing of pastures. The vegetation cover of India in large parts is on more natural in the real sense. Except in some inaccessible region like the Himalayas, the hilly region of central India and the marusthali, the vegetation of most of the areas has been modified at some places, or replaced or degraded by human occupancy.

Flora: The term flora is used to denote plants of a particular region or period.

Fauna: The species of animals are referred to as fauna.

FACTORS WHICH AFFECT DIVERSITY OF FLORA AND FAUNA

Land: Land affects the natural vegetation directly and indirectly. The nature of land influences the type of vegetation. 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 wild life.

Soil: Different types of soil provide basis for different types of vegetation. The sandy soils of the desert support cactus and thorny bushes while wet, marshy, deltaic soil support mangroves and deltaic vegetation. The hill slopes with some depth of soil have conical trees.

Temperature: the character are extent of vegetation are mainly determined by temperature along with humidity in the air, precipitation and soil. on the slopes of the Himalayas and the hills of the Peninsula above the height of 915 meters, low temperature affects the types of  vegetation and its growth. Temperature changes it from tropical, temperature and alpine.

Sun Light:  The variation in Sunlight received at different places is due to difference in latitude, altitude, season and duration of the day. Adequate sunlight in summer causes trees to grow faster.

Precipitation: Precipitation determines the density of vegetation. Areas of heavy rainfall have more dense vegetation as compared to other areas of less rainfall.

Importance of forests for Human life

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. it controls wind force and temperature and causes rainfall. It provides humus to the soil and shelter to the wildlife.

COSYSTEM   AND BIOME

Ecosystem: It is an integrated unit consisting of the community of living organisms and the physical environment in a particular area. Plants occur in distinct groups of communities in areas having similar climatic conditions. The nature of the plants in an area, to a large extent, determines the animal life in that area.

Biome: A very large ecosystems on land having distinct types of vegetation and animals life is called a biome. Biomes include both flora and fauna but it is mainly the plant formations which are used as the basis of their grouping. On the basis of the order of availability of soil, water and heat the world is divided into five principle biomes:

(i) Forest           (ii) Savanna        (iii) Grassland           (iv) Desert             (v) Tundra

TYPES OF VEGETATION

(a)  Tropical Evergreen:

(i) They are at their best in areas having more than 200 cm of rainfall with a short dry season.

(ii) In these forest trees grow up to 60 m & above.

(iii) These forest yield hard wood trees.

(iv) These forest are found in rainy parts of Western Ghats, Assam, West Bengal, Lakshadweep and Andaman & Nicobar Islands.

(v) Ebony, Mahogany, Rosewood, Rubber and Cinchona are some of the important trees.

(vi) In these forest large number of plant species are found at one place. it creates difficulty in their commercial exploitation.

(vii) Elephants, Monkey, Lemur and Deer are some common animals found in these forest.

(b) 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 a bout six to eight weeks in dry summer. on the basis of the availability of water, these forests are further divided into :-

Moist deciduous:

(i) These forests are found in the areas of 100 cm to 200 cm of rainfall.

(ii) Due to a longer dry season, the trees shed their leaves during the dry season.

(iii) Shisham, Bamboos, Sandalwood, Khair, Kusum, Arjun, Mulberry and Sal are the common trees found in these forests.

(iv)These forests cover a vast area of the country. Northeastern states, along the foot hills of the Himalayas, Jharkhand, West Orissa and Chhattisgarh and on the Eastern slopes of the Western Ghats.

Dry deciduous:

(i) These are found in areas having rainfall between 70 cm to 100 cm.

(ii) These are found in the rainier part of the peninsular plateau and the plains of Bihar and U.P.

(iii These are open stretches in which Teak, Sal, Peepal, Neem grow.

(iv) Most of these forests have been cleared for cultivation.

(v) In these forests, the common animals found are lion, tiger, pig, deer and elephant. a huge variety of birds, lizards, snakes, and tortoises are also found here.  

(c) The Thorn forests and Shrubs:

Tropical thorn forests occur in the areas which receive rainfall less than 70 cm. these consist of a variety of grasses and shrubs. In includes semi-arid areas of south west Punjab, Haryana, Rajasthan, Gujarat, Madhya Pradesh and Uttar Pradesh. In these forests, plants remain leafless for most part of the year and give an expression of shrub vegetation. Important species found are babul, kher and wild Date palm, Kikar, Neem, Khejri, Palas, etc.

(d)  Montain Forests:

In mountainous areas, the decrease in temperature with increasing altitude leads to the corresponding change in natural vegetation.

(i)  The wet temperate type of forests are between a height of 1000 and 2000 meters. evergreen broad-leaf tress   such as oaks and chestnuts predominate.

(ii) Between 1500 and 3000 meters, temperate forests containing coniferous trees like pine, deodar, silver fir, spruce and cedar, are found. These forests cover mostly the southern slopes of the Himalayas, places having high altitude in southern and north-east India. at higher elevations, temperate grasslands are common.

(iii)  At high altitudes, generally more than 3600 meters above 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.

(iv) Above Alpine vegetation Alpine grasslands are found. These are used extensively for grazing by nomadic tribes like the Gujjars and the Bakarwals. At higher altitudes, mosses and lichens form part of tundra vegetation.

(v) the common animals found in these frosts are Kashmir stag, spotted dear, wild sheep, jack rabbit, Tibetan antelope, yak, snow leopard, squirrels, shaggy horn wild ibex, dear and rare red panda, sheep and goats with thick hair.

Mangrove forests:

These are found in the areas which are under y\the influence of tides having accumulated mud and silt. Dense mangrove are the common varieties with roots of plants submerged under water. These forests are found in the deltas of Ganga, Mahanadi, Godavari and Kaveri. The most important tree is the Sundari tree after which the Sunderbans are named. The tree provides hard, durable and strong wood which is used for building boats and boxes. Royal Bangal Tiger is the famous animal in these forests. Turtles, crocodiles, gharials and snakes are also found in these forests.

FOREST CONSERVATION

Forests have an intricate interrelationship with life and environment. These provide numerous direct and indirect advantages to our economy and society. Hence, conservation of forests is of vital importance to the survival and prosperity of humankind. Accordingly, the Government of India proposed to have a nationwide forest conservation policy, and adopted a forest policy in 1952, which was further modified in 1988. According to the new forest policy, the Government would emphasis sustainable forest management in order to conserve and expand forest reserve on the one hand, and to meet the needs of local people on the other.

The forest policy aimed at:

(i) Bringing 33 per cent of the geographical areas under forest cover.

(ii) Maintaining environmental stability and to restore forests where ecological balance was disturbed.

(iii) Conserving the natural heritage of the country, its biological diversity and genetic pool.

(iv) Checks soil erosion, extension of the desert lands and reduction of floods and droughts.

(v) Increasing the forest cover through social forestry and afforestation on degraded land.

(vi) Increasing the productivity of forests to make timber, fuel, fodder and food available to rural population dependant on forests, and encourage the substitution of wood.

(vii) Creating of a massive people’s movement involving women to encourage planting of trees, stop falling of trees and thus, reduce pressure on the existing forest.

WILDLIFE 

Wildlife of India is a great natural heritage. It is estimated that about 4-5 per cent of all known plant and animal species on the earth are found in India. The main reason for this remarkable diversity of life forms is the great diversity of the ecosystem which this country has preserved and supported through the ages. India has more than 1200 species of birds, 2500 species of fish and between 5 to 8 percent of the world’s amphibians, reptiles and mammals. India is the only country in the world that has both tigers and lions. The Himalayas have a large range of animals that survive the bitter cold. Every species of animal has a role to play in the ecosystem; hence conservation is essential. Hunting and pollution is causing threat to animal species. To protect the flora and fauna of the country, the government has taken many steps. Fourteen biosphere reserves have been set up in the country to protect flora and fauna. 89 national Parks, 49 Wildlife Sanctuaries and Zoological Gardens are set up to take care of natural heritage.

Over the years, their habitat has been disturbed by human activities and as a result, their numbers have dwindled significantly. There are certain species that are at the brink of extinction.

Some of the important reasons for the declining wildlife are as follows:

(i)  Industrial and technological advancement brought about a rapid increase in the exploitation of forest resources.

(ii) More and more lands were cleared for agriculture, human settlement, roads, mining, reservoirs, etc.

(iii) Pressure on forests mounted due to lopping for fodder and fuel wood and removal of small timber by the local people.

(vi)Grazing by domestic cattle caused an adverse effect on wildlife and its habital.

(v) Hunting was taken up as a sport by the elite and hundreds of wild animals were killed in a single hunt. now commercial poaching is rampant.

(vi) Incidence of forest fire.

(a) wildlife conservation in India.

(i) fourteen biosphere reserves have been set up in the country to protect flora and fauna. four out of these, the Sunderbans in the West Bengal, Nanda Devi in Uttaranchal, the Gulf of Mannar in Tamil Nadu and the Nilgiris (Kerala, Karnataka and Tamil Nadu) have been included in the world network of Biosphere reserves.

(ii) financial and technical assistance is provided to many Botanical Gardens by the governmental projects have been introduced.

(iv) 89 National Parks, 492 Wildlife sanctuaries and Zoological gardens are set up to take care of Natural heritage.

BIOSPHERE RESERVES

A Biosphere Reserve is a unique and representative ecosystem of terrestrial and coastal areas which are internationally recognised within the framework of UNESCO’s Man and Biosphere (MAB) Programme. The Biosphere Reserve aims at achieving the three objectives as depicted in Figure.

There are 14 Biosphere Reserves in India (Table, Figure). four Biosphere Reserves,namely (i) Nilgiri ; (ii) Nanda Devi; (iii) Sunderbans; and (iv) Gulf of Mannar havebeen recognised by the UNESCO on World Network of Biosphere Reserves.

Q.1. What is Natural Vegetation?

Ans. 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 also known as Virgin Vegetation. Cultivated crops and fruits, orchards form part of vegetation but not natural vegetation.

Q.2. Differentiate between endemic and exotic species.

Ans. The natural 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.

Q.3. What do you understand by the terms flora and fauna?

Ans. The term flora is used to denote plants of a particular region or period. Similarly, the species of animals are referred to as fauna.

Q.4. Why the natural vegetation of India is undergoing various changes?

Ans. A. Increasing demand for cultivated land.

B. Development of industries and urbanization

C. Over grazing of pastures.

Q.5. Define a biome.

Ans. A very large ecosystem on land having distinct types of vegetation and animal life is known as a biome.

Q.6. Why is there an ecological imbalance?

Ans. Due to constant interference of man in the physical and biological environment, balance between the two has been disturbed resulting in ecological imbalance.

Q.7. What is an Ecosystem?

Ans. All the plants and animals in an area are interdependent and interrelated to each other in their physical environment. This interdependence and interrelationship forms an ecosystem.

Q.8. What do you understand by the term vegetation?

Ans. The assemblage of specific plants living in association with each other in a particular environmental framework is termed as vegetation.

Q.9. Name the four biosphere reserves which are a part of world network of biosphere reserves.

Ans. The Sundarbans in West Bengal, Nanda Devi in Uttarakhand, The Gulf of Mannar in Tamil Nadu and the Nilgiris (Kerela, Karnataka and Tamil Nadu).

Q.10. Which is the most dominant vegetation type of India?

Ans. Tropical Deciduous Forest (Monsoon Forest)

Q.11. Name those regions which have natural vegetation in real sense.

Ans. Some inaccessible regions like the Himalayas and the hilly region of Central India.

Q.12.Why the Tropical Evergreen forests are called so?

Ans. There is no definite time for trees to shed their leaves, as such, these forests appear to be green all the year round. Therefore, they are known as ‘evergreen forest’.

Q.13. Why are forests important for us?

Ans. Forests play a major role in enhancing the quality of environment as they modify local climate, control soil erosion, and regulate stream flow.

Q.14. Distinguish between extinct and endangered species.

Ans. Extinct species of plants and animals are those which have completely disappeared from our forest whereas endangered species are those which are on the verge of extinction. About 1300 plant species are endangered and 20 species are extinct.

Q.15. Define the following:

Ans. 1. National Park: These are the reserved forests where natural vegetation and wildlife are preserved in their natural environment. Eg. Kaziranga National Park

2. Wildlife Sanctuary: These are the portion of the natural forests where hunting and poaching of wild animals and birds are prohibited. Eg. Bharatpur Bird Sanctuary

3. Biosphere Reserve: The forest areas where all types of flora and fauna are preserved in their natural environment.

Q.16. How can you say that India is one of the major biodiversity of the world?

Ans. a. India is rated as one of the twelve mega biodiversity country of the world

b .India has 47000 plant species and 89000 species of animals.

c. India is tenth in the world and fourth in Asia in plant diversity.

d. India has 15000 flowering plants. They constitute 6% of the world’s total flowering plants.

e. India is also rich in non-flowering plants that include fern, algae, and fungi.

f. India has a huge variety of fish in its fresh and marine waters.

Q.17. Name a national park of Uttar Pradesh and Gujarat. Why are elephants found mainly in Assam, Kerela and Karnataka?

Ans. Uttar Pradesh – Dudwa and Gujarat – Gir Elephants are found mainly in Assam, Kerela and Karnataka because dense and high vegetation type that is tropical evergreen forests are found here for this herbivore animal.

Q.18. How the thorny plants conserve the moisture in them?

Ans. 1. Trees are scattered and have long roots penetrating deep into the soil in order to get moisture.

2. Leaves are in the form of spines in order to check the loss of moisture during transpiration.

3. Stems of the plants are thick and fleshy in order to conserve the water in them.

Q.19. Write down the natural habitat of various animals found in India.

Q.20.What are the factors influencing the variety of flora and fauna?

Ans. A. RELIEF

a. Land : The nature of land influences the type of vegetation. The fertile level land is generally devoted to agriculture. The undulating and rough terrains are areas where grasslands and forests develop and give shelter to a variety of wildlife.

b. Soil: Different types of soil provide basis for different types of vegetation. The sandy soil of the desert support cactus and thorny bushes while wet marshy deltaic soils support mangroves and deltaic vegetation. The hill slopes have conical trees.

B. CLIMATE

a. Temperature: The character and extent of vegetation is highly determined by temperature. On the slopes of the Himalayas and the hills of the Peninsula above the height of 915 metres, the fall in temperature affects the types of vegetation and its growth and changes from tropical to sub-tropical and alpine.

b. Photoperiod (sunlight): The variation in duration of sunlight at different places is due to differences in latitude, altitude, season and duration of day. Due to longer duration of sunlight, trees grow faster in summer. Hence, the southern slopes of Himalayas are covered with thick vegetation as compared to the northern slopes.

c. Precipitation: Areas of heavy rainfall have more dense vegetation as compared to other areas of less rainfall. Therefore, the western slopes of the Western Ghats covered with thick forests and not the eastern slopes.

Q.21. What steps are taken by the government to conserve flora and fauna of India?

Ans. 1. Fourteen biosphere reserves have been set up in the country to protect flora and fauna. Four out of these namely the sundarbans, Gulf of Mannar, The Nilgiris and the Nanda Devi have been included in the world network of Biosphere reserves.

2. Financial and technical assistance is provided to many Botanical Gardens by the government since 1992.

3. Project Tiger, Project Rhino and many other eco-developmental projects have been introduced.

4. 89 National Parks, 49 Wildlife Sanctuaries and zoological gardens are set up to take care of Natural heritage.

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