CBSE Notes | Class 9 | Social Science | Geography Chapter 5 - Natural Vegetation and Wildlife
The chapter notes will introduce students to India's different bio-forms ranking it the 12th mega bio-diversity country in the world. In the chapter you will learn about various factors that affect vegetation and wildlife of a region, types of vegetation cover, threats to flora and fauna and steps being taken for conservation of biodiversity.
Natural Vegetation and Wildlife in India
India’s vastness, its variation in landforms and different climatic conditions make it one of the 17 mega-biodiverse countries in the world. India has two biodiversity hotspots:
1. The Western Ghats or Sahyadris
2. The Eastern Himalayas
According to a 2010 study, India ranks 10th in the world and 4th in Asia in plant diversity boasting around 47,000 different plant species. It is home to around 15,000 flowering plants accounting for around 6% of world’s total.
Indian animal diversity stands at 1,02,161 species, which is equivalent to 6.52% of all the species across the globe. It is also rich in fish diversity in its fresh and marine waters.
What is natural vegetation or virgin vegetation?
It refers to those plant species which grow naturally on their own undisturbed by any human aid or activity. Orchards, fruits and cultivated crops are thus not a part of natural vegetation.
What are endemic and exotic species?
Species of plants and animals which are found in their natural habitat and within a defined geographical location are called as endemic or indigenous species of the region.
Exotic species on the other hand are be found away from their natural habitat. They are usually invasive in character and non-native to the specific geographical location.
What is flora and fauna?
Flora denotes the plants of a particular region whereas Fauna denotes the animals of a particular region.
What factors are responsible for biodiversity?
1. Relief Features – such as land, soil type
2. Climate – such as temperature, precipitation and photoperiod.
Effect of Relief Features on Biodiversity
Land: Land has direct and indirect effects on natural vegetation. The vegetation types in mountainous, plateau, and plain areas, as well as dry and wet regions is different as it is influenced by the nature of the land. Agriculture is practised at the fertile level and the undulating and difficult terrains are locations where grassland and forests grow, providing habitat for a wide range of wildlife.
Soil : Soil types also vary geographically. Different kinds of soils support different kinds of vegetation. Cactus and prickly shrubs thrive in the desert's sandy soils, while mangroves and deltaic flora thrive in the delta's damp, marshy soils. Conical trees grow on hill slopes with some soil depth.
Effect of Climate on Biodiversity
Temperature : The character and 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 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 duration of sunlight varies according to latitude, altitude, season, and day length. Summer trees grow more quickly due to the longer duration of sunlight.
Precipitation : The advancing southwest monsoon (June to September) and retreating northeast monsoons bring almost all of India's rainfall. Areas with high rainfall have more dense vegetation than areas with low rainfall.
Importance of Forests
Forests are a renewable resource that contribute significantly to environmental quality. They influence the surrounding climate, prevent soil erosion, regulate stream flow, support a diverse range of industries, provide employment for a large number of towns, and give panoramic or picturesque views for pleasure.
Additionally, they regulate wind speed and temperature, and precipitation occurs as a result of their actions. It helps the soil retain humus and provides habitat for wildlife.
Changes in India’s Natural Vegetation
In huge regions of India, the vegetation cover is no longer natural. It has changed dramatically as a result of a variety of circumstances, including increased need for arable land, industrial expansion, and mining.
Except for some inaccessible locations such as the Himalayas, central India's hilly region, and the marusthali, the vegetation of the majority of areas has been modified, replaced, or degraded by human habitation in some areas. urbanisation and pasture overgrazing
What is an ecosystem?
An ecosystem is a community of plants and animals that interact with each other in a physical environment. . These plants and are interdependent and linked to one another, forming an ecosystem.
Plants can be grouped into various communities based on similar environmental conditions. The type of animals at a given location is mostly determined by the plants in that area. When the flora changes, the fauna changes as well
What impact do humans have on a region's ecology?
Humans are an important part of the environment. They take advantage of the natural environment and wildlife. The abuse of these resources is due to human greed. They destroy the ecosystem by clearing the forest and slaughtering the animals.
As a result, several plant and animal species are in danger of extinction.
What are Biomes?
A biome is essentially a large land area with a wide variety of plant and animal life. These biomes can be classified based on their vegetation types.
Types of Vegetation in India
1. Tropical Evergreen Forests
2. Tropical Deciduous Forests
3. Tropical Thorn Forests and Scrubs
4. Montane Forests
5. Mangrove Forests
1. Tropical Evergreen Forests
Precipitation : These forests are only able to survive in areas which receive a lot of rain. They thrive in areas with more than 200 cm of rain and a short dry season. The trees can grow to be 60 metres tall or even higher.
Areas : They are found on western side of Western Ghats and the North-Eastern Himalayas.
Vegetation Type : The region has a luxuriant vegetation of all kinds – trees, shrubs, and creepers – because it is warm and wet throughout the year, giving it a multilayered structure. Trees do not shed their leaves at a set time and as a result, these forests are green all year.
Tree Varieties in Evergreen Forests : Ebony, mahogany, rosewood, rubber, and cinchona are some of the forest's commercially valuable trees.
Animals in Evergreen Forests : Elephants, monkeys, lemurs, and deer are common animals in these forests. The Assam and West Bengal jungles are home to the one-horned rhinoceros. Birds, bats, sloths, scorpions, and snails can also be found in these jungles.
2. Tropical Deciduous Forests
These are India's most widely distributed forests. They're also known as monsoon forests, and they're found all over the region where rainfall ranges from 200 to 70 cm. In the dry summer, these forest-type trees shed their leaves for about six to eight weeks.
They can be further divided on basis of precipitation:
Moist Deciduous (Receiving 100 cm – 200 cm of rainfall)
Areas : Northeastern states, along the foothills of the Himalayas, Jharkhand, West Orissa and Chhattisgarh, and on the eastern slopes of the Western Ghats.
Important Trees : Teak is the most dominant species of this forest. Bamboos, sal, shisham, sandalwood, khair, kusum, arjun, mulberry are other commercially important species.
Dry Deciduous (Receiving 70 cm – 100 cm of rainfall)
Areas : Rainier parts of the peninsular plateau and the plains of Bihar and Uttar Pradesh. A large part of these forests have been cleared for cultivation and grazing.
Important Trees : Teak, Sal, Peepal, Neem
Animals in Deciduous Forests : Lion, tiger, pig, deer and elephant. A huge variety of birds, lizards, snakes, and tortoises are also found here.
3. Thorn Forests and Scrubs
Precipitation : This type of natural vegetation is found in areas with less than 70 cm of rainfall.
Areas : They are found in semi-arid areas of Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Uttar Pradesh, and Haryana in the northwestern part of the country.
Vegetation Type : Thorny trees and shrubs are common in these areas. Trees are scattered throughout the area, with long roots that reach deep into the soil in search of moisture. To save water, the stems are succulent. To reduce evaporation, the leaves are mostly thick and small. In arid areas, these forests give way to thorn forests and scrubs.
Tree and Plant Variety: The main plant species are acacias, palms, euphorbias, and cacti.
Animals in Thorn Forest and Scrubs : Rats, mice, rabbits, fox, wolf, tiger, lion, wild ass, horses and camels.
4. Montane Forests
Precipitation : These type of forests are found at higher elevations receiving around 150 cm – 300 cm of rainfall.
Areas : These forests primarily cover the southern Himalayan slopes, as well as high-altitude areas in southern and north-east India.
Vegetation Type and Plant Variety: The change in natural vegetation in mountainous areas is accompanied by a decrease in temperature with increasing altitude. As a result, there is a natural vegetation belt succession in the same order as we see from tropical to tundra regions.
Based on altitude the vegetation type can be classified into 3 categories:
a) Wet Temperate Forests (1000 m – 2000 m): Evergreen broadleaf trees such as Oak and Chestnuts
b) Temperate Forests and Grasslands (1500 m – 3000 m) : Coniferous trees such as pine, deodar, silver fir, spruce and cedar. Grasslands can be found at higher elevations.
c) Alpine Forests and Grasslands (Above 3600 m) : Silver fir, junipers, pines, and birches are among the forest's most common trees. As they get closer to the snow line, however, they become shorter. They eventually merge into the Alpine grasslands through shrubs and scrubs which are used for grazing cattle by nomadic tribes such as Bakkarwals and Gujjars. At higher altitudes, mosses and lichens form part of tundra/alpine vegetation.
Animals in Montane Forests :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 are common animals found in these forests.
5. Mangrove Forests
Precipitation : Mangroves are found in coastal regions having well formed deltas. They are found in brackish waters and normally receive around 200 cm of rainfall.
Areas : They can be found along tide-influenced coasts having accumulation of mud and silt. Primarily found in deltaic regions of rivers Mahanadi, Godavari, Krishna, Kaveri, Ganga and Brahmaputra.
Vegetation Type : The most common types of mangroves are dense mangroves, which have their roots submerged in water. Sundari trees, which provide durable hard wood, can be found in the Ganga-Brahamaputra delta.
Tree and Plant Variety: Some parts of the delta also have palm, coconut, keora, and agar trees.
Animals in Thorn Forest and Scrubs : Turtles, crocodiles, gharials, snakes and the famous Royal Bengal Tiger which is endemic to Sunderban delta
Some Medicinal Plants of India
India has long been known for its herbs and spices. Ayurveda describes over 2,000 plants, of which 500 are used regularly. The Red List of the World Conservation Union lists 352 medicinal plants, 52 of which are critically endangered. Popular plants in India include:
Sarpagandha: An Indian herbal remedy for high blood pressure.
Jamun : The ripe fruit juice is used to make vinegar, which is carminative, diuretic, and digestive. The seed powder is used to treat diabetes.
Arjun: Leaf juice relieves earache. It also controls blood pressure.
Babool: Leaves treat eye sores. The gum is a tonic.
Neem: Rich in antibiotics and has antibacterial properties.
Tulsi Plant: Treats cough and cold.
Kachnar: Treats asthma and ulcers. The buds and roots help digestion.
Wildlife in India
India's fauna is as diverse as its flora. It has 90,000 animal species and 2,000 bird species making up 13% of the world's total diversity. There are around 2,500 fish species which make up nearly 13% of the world's stock. It also has 5% to 8% of the world's amphibians, reptiles, and mammals.
Some Important Animals in India
Elephants : Elephants are the most majestic mammals. They are found in Assam, Karnataka, and Kerala.
One Horned Rhinoceroses : They are extremely vulnerable to poaching for their horns and are found in terai and duar plains of Assam and West Bengal.
Wild Ass : They can be found in the Indian Wild Ass Sanctuary in Rann of Kuchh. They are near threatened.
Camels : Camels can be found in the Thar desert and are now mostly domesticated. Their population in wild has been declining and is a cause of concern.
Tigers: Tigers are found in the forests of Madhya Pradesh, Maharashtra, Karnataka, the Sundarbans of West Bengal and the foothiils of Himalayan region. India has the maximum number of tigers in the world.
Lions : Lions in India can be found in the their only natural habitat in India – the Gir Forests of Gujarat. India is the only country in the world to have both lions and tigers in wild.
Leopards and Panthers : They can be found close to tiger habitats in India along with other members of the cat family. The snow leopard can however be only found in the upper reaches of Himalayas.
Other animals found in India include Indian bison, nilgai (blue bull), chousingha (four horned antelope), gazel, and various species of deer. It also has a variety of monkeys.
Animals found in Himalayas : The Himalayas are home to hardy animals which can survive in extreme cold such as Yak (A shaggy horned wild ox weighing upto 1 tonne), Tibetan Antelope, Bharal (Blue Sheep), Wild Sheep, Kiang (Tibetan Wild Ass), Ibex, Bear, Snow Leopard and Red Panda (Endemic to Eastern Himalayas)
Animals found in Rivers, Lakes and Coastal Areas : Turtles, Gharials and Crocodiles
Birds found in India : India is rich in colourful birds which inhabit its forests and wetlands such as Peacocks, Pheasants, Ducks, Cranes, Parakeets and Pigeons.
Migratory birds flock to India's wetlands in large numbers. Birds such as the Siberian Crane flock in large numbers during the winter. The Rann of Kachchh is one such bird-friendly location. Thousands of flamingos, with their brilliant pink feathers flock to a spot where the desert meets the sea to build nest mounds out of the salty mud and raise their young. It is one of the country's many spectacular sights.
Why is conservation of species important?
Every species has a role to play in the ecosystem.
We chose our crops from a biodiverse environment, i.e. an edible plant reserve. We also experimented with and selected a variety of medicinal plants.
The animals were chosen from a large stock of milch animals provided by nature. They also supplied us with draught power, transportation, meat, and eggs.
The fish are a good source of nutrition.
Many insects aid in the pollination of crops and fruit trees and provide biological control over harmful insects.
Threats to Flora, Fauna and Ecosystems
Because of human overexploitation of plant and animal resources, the ecosystem has been disrupted. Around 1,300 plant species are threatened, and 20 are extinct. Many animal species are also threatened, and some have become extinct.
The main causes contributing to this imbalance and threat to nature are:
1. Commercial hunting by greedy hunters.
2. Pollution from chemical and industrial waste
3. Acid deposits
4. Introduction of alien species
5. Deforestation : Reckless cutting of forests to make land suitable for cultivation and human habitation
Steps by Government of India to protect Flora and Fauna of India
The Government of India has taken numerous steps to protect the country's flora and fauna.
1. Setting up of Biosphere Reserves : The country has 18 biosphere reserves to protect its flora and fauna. Here are 18 biosphere reserves in India:
Cold Desert, Himachal Pradesh
Nanda Devi, Uttrakhand
Dehang-Debang, Arunachal Pradesh
Panna, Madhya Pradesh
Pachmarhi, Madhya Pradesh
Achanakmar-Amarkantak, Madhya Pradesh-Chhattisgarh
Kachchh, Gujarat (Largest Area)
Sundarban, West Bengal
Seshachalam, Andhra Pradesh
Agasthyamala, Karnataka-Tamil Nadu-Kerala
Nilgiri, Tamil Nadu-Kerala (First to be Included)
Gulf of Mannar, Tamil Nadu
Great Nicobar, Andaman & Nicobar Island
The Sunderbans in West Bengal, Nanda Devi in Uttarakhand, the Gulf of Mannar in Tamil Nadu, and the Nilgiris (Kerala, Karnataka, and Tamil Nadu) are four of these reserves that have been added to the world network of biosphere reserves.
2. Providing Financial Assistance : Since 1992, the government has provided financial and technical assistance to a number of Botanical Gardens.
3. Special Projects : Project Tiger, Project Rhino, Project Great Indian Bustard, and a slew of other eco-developmental initiatives have been unveiled.
4. Setting up of National Parks, Wildlife Sanctuaries and Zoological Gardens : To protect natural heritage, 106 national parks, 566 wildlife sanctuaries, and several zoological gardens have been established and many are proposed to be included soon.