Natural Vegetation and Wildlife Class 9 Notes - CBSE Geography PDF Download

                                     CH : NATURAL VEGETATION AND WILDLIFE

DIVERSITY OF INDIA:-

Our country India is one of the twelve mega bio-diversity countries of the world.

 With about 4700 plant species India occupies 10^th place the world and 4^th place in Asia in plant diversity.

 There are about 15000 flowering plants in India which accounts for 6 percent in the world total number of flowering plants.

 India has approximately 90,000 species of animal as well as a rich variety of aquatic animals.

Natural vegetation: It refers to a plant community which has grown naturally without human aids and has been left undisturbed by human for a  long time. This is termed as Virgin vegetation.

Flora: Plants of a particular region. , Fauna: Animal of a particular region.

Factors that affect Biodiversity of an area:-

A) RELIEF

(I)LAND: It 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 grasslands and woodlands develops and give shelter to a variety of wildlife.

(2)SOIL: The soil also varies over space. Different type of soil provides different types of vegetation. Sandy soil of deserts supports cactus and thorny bushes while marshy deltaic soils support mangroves and deltaic vegetations. The hill slopes with some depth of soil have conical trees.

CLIMATE

Temperature and Humidity: Temperature, humidity in air, precipitation and soil are the main factors which determine the character and extent of vegetation. An area with high temperature and high humidity supports evergreen forest, while an area with high temperature and low humidity supports thorny bushes. On the slopes of Himalaya, temperature affects the type of vegetation changing it from tropical to subtropical temperate and alpine vegetation.

Photoperiod (Sunlight): The duration of sunlight is called photoperiod. Photoperiod depends on latitude, altitude, season and duration of the day. Trees grow faster in summer because of longer photoperiod.

Precipitation: If an area gets heavy rainfall, it is suitable for the growth of dense vegetation. On the other hand, an area with scanty rainfall is suitable for thorny bushes. In India almost the entire rainfall is brought by advancing southwest monsoon (June -September) and retreating northeast monsoon.

Ecosystem: All the plants and animals in an area are interdependent and interrelated on each other in their physical environment make the ecosystem. The nature of plant to a large extent determines the animal life of that area.

* A very large ecosystem on land having different types of vegetation and animal life is called a biome. Biomes are identified on the basis of plants.

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Several factors due to which India’s natural vegetation has gone through many changes are:-

(i) Growing demands for cultivable land

(ii) Development of industries and mining.

(iii) Urbanization and over-gazing

TYPES OF VEGETATION

The following major types of vegetation may be identified in our country

(i) Tropical Rain Forests

(ii) Tropical Deciduous Forests

(iii) Tropical Thorn Forests and Scrubs

(iv) Montane Forests

(v) Mangrove Forests

Tropical Rain 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 meters or even above.

Since the region is warm and wet throughout the year, it has a luxuriant vegetation of all kinds – trees, shrubs, and creepers giving it a multilayered structure. These forests appear green all the year round. There is no definite time for trees to shed their leaves.

 Some of the commercially important trees of this forest are ebony, mahogany, rosewood, rubber and cinchona.

 The common animals found in these forests are elephants, monkey, lemur and deer. The one horned rhinoceros are found in the jungles of Assam and West Bengal. Besides these animals plenty of birds, bats, sloth, scorpions and snails are also found in these jungles.

Tropical Deciduous Forests

These are the most widespread forests of India. They are also called the monsoon forests.

They 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 and dry deciduous.

The moist deciduous forest is found in areas receiving rainfall between 200 and 100 cm. These forests exist, therefore, mostly in the eastern part of the country – northeastern states, along the foothills of the Himalayas, Jharkhand, West Orissa and Chhattisgarh, and on the eastern slopes of the Western Ghats. Teak is the most dominant species of this forest. Bamboos, sal, shisham, sandalwood, khair, kusum, arjun, mulberry are other commercially important species.

 The dry deciduous forests are found in areas having rainfall between 100 cm and 70 cm. These forests are found in the rainier parts of the peninsular plateau and the plains of Bihar and Uttar Pradesh. Its large part is cleared for cultivation.There are open stretches in which teak, sal, peepal, neem grows.

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.

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. The stems are succulent to conserve water. Leaves are mostly thick and small to minimize evaporation.

 These forests give way to thorn forests and scrubs in arid areas.

 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(cone-shaped) 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 altitude generally<3600m above sea level, temprate forest and grassland give way to Alpine vegetation.

The shrubs and scrubs are extensively used for gazing by nomadic tribes.

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.

At higher altitudes mosses and lichens form part of Tundra vegetation.

Mangrove Forests

The mangrove tidal forests are found in the areas of coasts influenced by tides. Mud and silt get accumutated on such coasts.

Dense mangroves are the common varieties with roots of the plants submerged under water.

 The deltas of the Ganga, the Mahanadi, the Krishana, the Godavari and the Kaveri are covered by such vegetation.

 Royal Bengal Tiger is the famous animal in these forests. Turtles, crocodiles, gharials and snakes are also found in these forests.

WILD LIFE

• India has approximately 90000 animal species
• .The country has about 2,000 species of bird. They constitute 13% of the world’s total.
• There are 2456 species of fish which accounts for nearly 12% of the world’s stock.
• It also shares between 5-8% 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. Indian bison, nilgai (blue bull), chousingha (four horned antelope), gazel and different species of deer are some other animals found in India. It also has several species of monkeys.
•  India is the only country in the world that has both tigers and lions.
• The natural habitat of the Indian lion is the Gir forest in Gujarat.
• Tigers are found in the forests of Madhya Pradesh, the Sundarbans of West Bengal and the Himalayan region
• Birds life in India is colourful. Peacock, Pheasants, ducks, cranes and pigeons are some of the birds inhabiting the forest and wetlands of our country.

ROLES PLAYED BY EVERY SPECIES ARE :-

They provide milch animal, draught power, transportation, meat and egg.

The fish  provide nutritive food(vitamin A & K).

Many insects helps in pollination and fruit trees and exert biological control on such insects, which are harmful.

Reptiles like snake kill pest that destroys the crop.

The steps taken by government to protect flora and fauna are:-

IMPORTANCE OF FOREST:-

(i) They are renewable resources and play a major role in enhancing the quality of environment.

(ii)They modify local climate, control soil erosion, regulate stream flow, support a variety of industries, provide livelihood to many communities and offer panoramic or scenic view for recreation.

(iii) It controls wind force, regulates temperature and causes rainfall.

(iv) It provides humus to the soil and shelter to the wildlife

STEP TAKEN BY GOVT. TO PROTECT FLORA AND FAUNA ARE:-

(i)The wildlife protection act was passed in 1972.

(ii)Fourteen biosphere reserves has been set up throughout the country. Four out of them are the sunder ban in the west Bengal, Nanda Devi in Uttrakhand, the gulf of mannar in Tamil Nadu, the nilgiris (Karnataka, Kerela and Tamil Nadu).

(iii)Financial and technical assistance is provided in many Botanical gardens since 1992.

(iv)Project Tiger, Project Rhino, Project (Great Indian Bustard, Red Panda, Leopard) and many other eco-development projects have been introduced.

(v)89 National Parks, 49 Wildlife Sanctuaries and zoological gardens are set up to take care of natural heritage(+1wildlife sanctuary)

Due to interference of human beings, about 1300 plant species are endangered and 20 species are extint.

Causes due to which some plants and animals are endangered are:-

• Hunting by greedy hunters.
• Pollution due to chemical and industrial waste and acid deposit
• Introduction of alien species 
• Reckless cutting of trees to bring more land under cultivation

 DO YOU KNOW?

• The Gir forest is the last remaining habitat of the Asiatic loin.
• According to the India state of forest report 2011, the forest cover in India is 21.05%.
• The virgin vegetation which are purely Indians are known as endemic or indigenous species but those which  had come from outside India  are known as exotic species.

                                                     MIGRATORY BIRDS

Some of the wetlands of India are popular with migratory birds. During winter, bird, such as Siberian crane come in large numbers. One such place favorable with birds is the Rann of Kachchh. At a place where desert merges with the sea, flamingo with their brilliant, pink plumage, come in thousand to build nest mounds from the salty mud and raise their young ones. It is one among many extraordinary sights.

MEDICINAL PLANTS

India is known for its herbs and spices from ancient times. Some 2,000 plants have been described in Ayurveda and at least 500 are in regular use. The World Conservation Union’s Red list has named 352 medicinal plants of which 52 are critically threatened and 49 endangered. The commonly used plants in India are:

Sarpagandha : Used to treat blood pressure; it is found only in India.

Jamun: The juice from ripe fruit is used to prepare vinegar which is carminative and diuretic, and has digestive properties. The powder of the seed is used for controlling diabetes.

Arjun: The fresh juice of leaves is a cure for earache. It is also used to regulate blood pressure.

Babool: Leaves are used as a cure for eye sores. Its gum is used as a tonic.

Neem: Has high antibiotic and antibacterial properties.

Tulsi Plant: Is used to cure cough and cold.

Kachnar: Is used to cure asthma and ulcers. The buds and roots are good for digestive problems.