CBSE NCERT Class IX (9th) | Social Studies | Geography
Chapter : Natural Vegetation and Wildlife
Biodiversity - Natural Vegetation and Wildlife
A plant community that has grown naturally without human aid is called natural vegetation. Natural vegetation that has been left undisturbed by humans for a long time is called virgin vegetation. Sacred groves are forests that have been protected for ages by traditional societies.
Virgin vegetation that is purely Indian is known as endemic or indigenous species. Plants that have come from outside India are termed exotic plants like some species of orchids.
Biodiversity in a region typically refers to its flora as well as fauna. Flora refers to the plants of a particular region or period. Fauna is the collective term for the species of animals in a particular region or period.
Biodiversity is caused by relief, climate and ecosystem in a region.
Relief in a region includes the land and the soil type found there. Different types of soils provide the basis for different types of vegetation.
Climate refers to three aspects of a region, the temperature, the photoperiod or duration of sunlight, and precipitation. These aspects, along with the soil and land type, determine the type and extent of vegetation.
As the temperatures rises, the type of vegetation slowly changes. The factors that determine the duration of sunlight are: The latitude of a region, The altitude of a region, and The duration of the day.
Areas of heavy rainfall typically have more dense vegetation as compared to areas of less rainfall.
Forests and Ecosystem
Forests are important as they are renewable resources that affect our environment in a variety of ways. They control climate, soil erosion and pollution. Forests support a variety of industries, helping provide livelihood for many communities.
There are very few areas left in India where the vegetation can be called natural in the true sense of the word like the Himalayas, the hilly region of Central India and the marusthali, parts of the desert. According to the Environment Atlas of India, June 2001, the actual forest cover in India in 2001 was only 20.55%.
A number of factors have caused extensive modification of vegetation and depletion of forest cover:
- Growing demand for cultivated land,
- The development of industries and mining,
- Urbanisation, and
- Over-grazing of pastures.
The Van Mahotsav is a forest festival started in 1950 by K. M. Munshi with the purpose to create enthusiasm among the masses for forest conservation and planting trees. Vegetation varies across areas because plants grow in distinct groups of communities, where each community belongs to an area with similar climatic conditions.
Together, the flora, the fauna and the physical environment of an area form an ecosystem. Human beings have a huge impact on an ecosystem. They utilize the vegetation and wild life, for food, medicine, and a variety of other purposes. When the utilization of these resources is not regulated, ecological imbalance can result.
A very large ecosystem on land with distinct types of vegetation and animal life is called a biome. An ecosystem can be as large as a desert and as small as a puddle. A biome is much bigger than an ecosystem.
Biomes are identified on the basis of plants. Mountains, deserts, grasslands, oceans and wetlands are all examples of biomes.
Types of Vegetation
The major types of vegetation in India are tropical evergreen forests, tropical deciduous forests, tropical thorn and scrubs forests, montane forests and mangrove forests.
Tropical evergreen forests are characterized by heavy rainfall and a warm climate. The commercially important trees grown in this area are ebony, mahogany, rosewood, rubber and cinchona. These forests also have a variety of animals like elephants, monkey, lemur and deer and various birds, bats, sloth, scorpions and snails.
Tropical deciduous forest makes up most of the forest area in India. These forests depend on the monsoon, and are also known as monsoon forests. Rainfall in these areas ranges from 70 to 200 cm. The areas that receive between 100 and 200 cm rains are known as moist deciduous, like along the foothills of the Himalayas, Jharkhand, western Orissa, Chhattisgarh, and the eastern slopes of the Western Ghats. Commercially important trees here include teak, bamboo, sal, shisham, sandalwood, khair, kusum, arjun and mulberry.
The areas that receive between 70 and 100 cm rainfall are classified as dry deciduous forests like the plains of Bihar and Uttar Pradesh. These are sparsely populated with the teak, sal, peepal and neem trees. The animals found here are elephants, lions, tigers and deer with variety of birds, lizards, snakes and tortoises.
Unlike evergreen and deciduous forests, the vegetation in thorn forests and scrubs is restricted to thorn plants and scrubs due to scanty rainfall. The rainfall is below 70 cm like the semi-arid areas of Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Uttar Pradesh and Haryana.
The stems of these plants are fleshy to conserve water for a longer period. The leaves are like thorns to minimise evaporation. Trees like the acacias, palms, euphorbias and cacti are common here with animals like rabbits, foxes, wolves, tigers, lions, horses and camels.
Montane forests are found in mountainous regions primarily in Jammu and Kashmir and Arunachal Pradesh. These are very different in their make-up from other types of forests, as the temperature and soil conditions are different on different altitudes.
The animals found here are the Kashmir stag, spotted deer, wild sheep, jack rabbit, Tibetan antelope, yak and snow leopard.
A tree-line is the edge of the habitat, beyond which there is no vegetation due to severe weather conditions.
The mangrove forests are usually found in coastal areas. Mangroves are a variety of plants and trees with their roots submerged in water. Dense mangrove forests are found in the deltas of the Ganga, the Mahanadi, the Godavari, the Krishna, and the Kaveri. Wild animals such as the Royal Bengal Tiger, crocodile, gharial, turtle and snake are found here.
Wildlife and Conservation of Flora and Fauna
India has a rich biodiversity and is home to around 1.6 million or nearly 8% of all the species of flora and fauna found in the world. India is also home to over 86,000 species of fauna including birds, insects, and land and water animals.
Besides being the only country to have both lions and tigers in its forests, India is one of the few countries that have a habitat to support large land animals like the elephant.
The Himalayas harbour some large land animals like the yak and the shaggy-horned wild ox found in the freezing high altitudes of Ladakh. Some rare species of wild animals include the snow leopard, the red panda, the ibex and the Himalayan brown bear.
The wildlife in the Indian rivers, lakes and coastal areas is equally rich with various species of reptiles like crocodiles and gharials, water snakes and turtles. There are over 940 different species of fish in India.
In order to preserve world biodiversity, and our natural heritage, fourteen biosphere reserves have been set up in the country.
Four have been included in the world network of biosphere reserves. They are the Sunderban in West Bengal, the Nanda Devi in Uttaranchal, the Gulf of Mannar in Tamil Nadu, and the Nilgiris spanning across Kerala, Karnataka and Tamil Nadu.
The government also provides financial and technical support for many of the Botanical Gardens, since 1992. To protect wildlife, the Government of India has introduced Project Tiger, Project Rhino and Project Great Indian Bustard.
In addition, there are 89 national parks, and 490 wildlife sanctuaries and zoological gardens in India to take care of our flora and fauna.
As per IUCN specifications, the species of flora and fauna can be classified as normal, extinct, endangered, vulnerable, rare or endemic.
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