Environmental Studies

 Important Notes

Part 21

• Our country 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 as ferns,
  algae and fungi. India also has 89,000 species
  of animals as well as a 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
  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.
• 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.
• The term flora is used to denote plants of
  a particular region or period. Similarly, the
  species of animals are referred to as fauna.
• 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.
• The soils also vary over space. 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.
• 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.
• 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 other areas of less rainfall.
• 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 wild life.
  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 no more natural in the real sense. Except in
  some inaccessible regions 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.
• 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. When
  the vegetation is altered, the animal life also
  changes. 
• All the plants and animals in an area
  are interdependent and interrelated to each
  other in their physical environment, thus, forming an ecosystem. 
• Human beings are
  also an integral part of the ecosystem. They utilise the vegetation and
  wild life. The greed of human beings leads to
  over utilisation of these resources. They cut
  the trees and kill the animals creating
  ecological imbalance. As a result some of the
  plants and animals have reached the verge
  of extinction. 
• A very large ecosystem
  on land having distinct types of vegetation and
  animal life is called a biome. The biomes are
  identified on the basis of plants.

 

 

 

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 metres 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. There
  is no definite time for trees to shed their leaves.
  As such, these forests appear green all the year
  round. 
• 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 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 and
  dry deciduous. The former 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. There are open stretches
  in which Teak, Sal, Peepal, Neem grow. A large
  part of this region has been cleared for
  cultivation and some parts are used for grazing. 
• 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. As such, there is a succession of
  natural vegetation belts in the same order as
  we see from the tropical to the tundra region.
  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. 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.
  At high altitudes, generally more than 3,600
  metres 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. However, they
  get progressively stunted as they approach
  the snow-line. Ultimately through shrubs and
  scrubs, they merge into the Alpine
  grasslands. 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. 
• 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. 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. In the Ganga-Brahamaputra delta, sundari trees are
  found, which provide durable hard timber.
  Palm, coconut, keora, agar, 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.

 

MEDICINAL PLANTS 

India is known for its herbs and spices from ancient times. Some 2,000 plants have been described in Ayurveda
and atleast 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.

 

• Like its flora, India is also rich in its fauna. It
  has more than 89,000 of animal species. The
  country has more than 1200 species of birds.
  They constitute 13% of the world’s total. There
  are 2500 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. 
• Indian bison, nilgai (blue bull),
  chousingha (four horned antelope), gazel and ferent 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. Leopards too are
  members of the cat family. They are
  important among animals of prey.
• The Gir Forest is the
  last remaining habitat
  of the Asiatic lion.
• The Himalayas harbour a hardy range of
  animals, which survive in extreme cold.
  Ladhak’s freezing high altitudes are a home to
  yak, the shaggy horned wild ox weighing
  around one tonne, the Tibetan antelope, the
  bharal (blue sheep), wild sheep, and the kiang
  (Tibetan wild ass). 
• Furthermore, the ibex, bear,
  snow-leopard and very rare red panda are
  found in certain pockets.
  In the rivers, lakes and coastal areas,
  turtles, crocodiles and gharials are found. The latter is the only representative of a variety of
  crocodile, found in the world today. 
• Bird life in India is colourful. Peacocks,
  peasants, ducks, parakeets, cranes and
  pigeons are some of the birds inhabiting the
  forests and wetlands of the country. 
• We have selected our crops from a bio-diverse environment i.e. from the reserve of
  edible plants. We also experimented and
  selected many medicinal plants. The animals
  were selected from large stock provided by
  nature as milch animal. They also provided
  us draught power, transportation, meat,
  eggs. The fish provide nutritive food. Many
  insects help in pollination of crops and fruit
  trees and exert biological control on such
  insects, which are harmful. Every species has
  a role to play in the ecosystem. Hence,
  conservation is essential. As has been
  mentioned earlier due to excessive
  exploitation of the plants and animal
  resources by human beings, the ecosystem has been disturbed. About 1,300 plant
  species are endangered and 20 species are
  extinct. Quite a few animal species are also
  endangered and some have become extinct. 
• 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 inhabitation, are also
  responsible for the imbalance.

 

To protect the flora and fauna of the
county, the government has taken many steps. 

(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 Biosphese reserves. 

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

(iii) Project Tiger, Project Rhino, Project Great
Indian Bustard and many other eco-developmental projects have been
introduced. 

(iv) 89 National Parks, 49 Wildlife sanctuaries
and Zoological gardens are set up to take
care of Natural heritage. 

 

All of us must realise the importance of the
natural ecosystem for our own survival. It
is possible if indiscriminate destruction of
natural environment is put to an
immediate end.

 

 

 

Fourteen Bio-reserves 

• Sunderbans 

• Simlipal 

• Gulf of Mannar 

• Dihang-Dibang 

• The Nilgiris 

• Dibru Saikhowa 

• Nanda Devi 

• Agasthyamalai 

• Nokrek 

• Kanchenjunga 

• Great Nicobar 

• Pachmari 

• Manas 

• Achanakmar-Amarkantak

 

Migratory Birds 

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

 

 

 

Questions and Answers

 

Ques 1 To which one of the following types of vegetation does rubber belong to? 

(a) Tundra 

(b) Himalayan 

(c) Tidal 

(d) Tropical Evergreen

Ans- (d) Tropical Evergreen

 

Ques 2 Cinchona trees are found in the areas of rainfall more than 

(a) 100 cm 

(b) 70 cm 

(c) 50 cm 

(d) less than 50 cm 

Ans- (a) 100 cm

 

Ques 3 In which of the following state is the Simlipal bio-reserve located? 

(a) Punjab 

(b) Delhi 

(c) Orissa 

(d) West Bengal 

Ans- (c) Orissa

 

Ques 4 Which one of the following bio-reserves of India is not included in the world
network of bioreserve? 

(a) Manas 

(b) Gulf of Mannar 

(c) Dihang-Dibang 

(d) Nanda devi

Ans- (a) Manas

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#NCERT Environmental Studies (EVS) important notes Part 20 for AEES, KVS, NVS, DSSSB, UPTET, REET, CTET, BTET, MPTET, HTET and All other Teaching Exams