Top 6 Main Types of Natural Habitats ! Total Information !! Biological Sciencess !!!

Top 6 Main Types of Natural Habitats

Apart from the biogeographic classifications described above ecosystems can also be demarcated on the basis of purely geographical or geological features like mountains, islands, valleys, plateaux, oceans; on the basis of vegetative cover like forests, grasslands, mangroves and deserts; on the basis of climatic conditions like arid and semi-arid areas, permanently snow-bound areas, high rainfall areas; on the basis of soil characteristic and other such criteria.

In some descriptions the biomes/ecosystems are clubbed together into very general habitat classifications.

The main natural habitat types are

1. Forests

The forest cover of the country is placed at 633 397 sq km according to the forest survey of India assessment (1997). This presents 19.27% of India’s total geographical areas. India is endowed with diverse forest types ranging from the Tropical wet evergreen forests in North-Eastern to the Tropical thorn forests in the Central and Western India.

2. Grasslands

In India the spread of grassland and shrubland is put at 12% of the total landmass while the planning commission (1989) and Grasslands and Fodder research Institute, Jhansi gives an estimate of about 3.7 to 3.9%. The diversity of grasslands in India is high ranging from semi-arid pastures of the western part of the Deccan peninsula, the humid, semi-waterlogged tall
grassland of the Terai belt, the rolling shola grasslands of the western ghat hilltops, and the high-altitude alpine pastures of the Himalayas.

3. Wetlands

Wetlands cover 3% of the Indian landmass, or nearly 100 000 sq. Km. Wetlands in India harbor a vast variety of life forms that are a part of the complex food of these transitional ecosystems.
About 320 species of birds are associated with the Indian Wetlands. Apart from birds, the wetlands support a diverse population of plants and animals including 150 species of amphibians.

Wetlands are the habitat of some of the world’s endangered and threatened flora and fauna. The Western and Central flock of Siberian crane, one of the most endangered cranes in the world, uses Keoladeo as its winter site. The brown antlered deer (Cervus eldi eldi) or ‘sangai’ is found only in phumadis (floating landmasses) of Lok Tak Lake. Gahirmatha beach is a major breeding site of olive ridley turtles. Chilka is the habitat of many threatened species such as green sea turtle, Hawksbill turtle, dugong, and blackbuck.

4. Mangroves

Government of India estimated mangrove cover of 674 000 ha, which is about 7% of the world’s mangrove. Mangroves are salt-tolerant ecosystems in tropical and subtropical regions. These ecosystems are largely characterized by assemblage of unrelated tree genera that share the
common ability to grow in saline tidal zone. India harbours some of the best mangroves swamps in the world, located in the alluvial deltas of Ganga, Mahanadi, Godavari, Krishna, and Cauveri rivers and on the Andaman and Nicobar group of Islands. The largest stretch of mangroves in the country lies in the Sunderbans in West Bengal covering an area of about 4,200 sq. km.

The predominant mangroves species are Avicennia officinalis, Excoecaria agallocha, Heritiera fomes, Bruguiera parviflora, Ceriops decandra, Rhizophora mucronata and Xylocarpus granatum.
Mangroves also harbour a number of molluscs, polychaetes and honeybees. The Indian mangroves are host to 105 species of fish, 20 kinds of shellfish, and 229 crustacean species.

The Royal Bengal tiger is found in the Sunderban mangroves. Different species of monkeys, otters,deer, fishing cats, snakes and wild pigs are common. A total of 117 species of migratory and residential birds have been reported. The most common birds are flamingos, storks, sea eagles,
kites, kingfishers, sandpipers, bulbuls, and whistlers.

5. Coral reefs

Accurate estimates of coral reef extent in the world are not available. A rough estimate puts it at 600 000 sq Km (Smith 1978) out of which 60% occurs in the Indian Ocean region and most of it in south-east Asia. The coral reef cover in Indian waters is roughly estimated upto 19,000 sq.

Km (Wafar 1992). Indian reefs belong to the following categories:
1. PalkBay and Gulf of Mannar : Fringing
2. Gulf of Kachchh : Fringing, Patchy
3. Andaman and Nicobar Islands : Fringing
4. Lakshadeep Islands : Atolls
5. Central West coast : Patchy

The diversity of the Indian coral reefs is very impressive with about 200 coral species belonging to 71 genera. The richest being Andaman and Nicobar Islands which alone harbors 179 species.

6. Deserts

In India, deserts extend over about 2% of the landmass. Three kinds of deserts are noticeable in India:

1. The sand desert of western Rajasthan and neighbouring areas.
2. The vast salt desert of Gujarat
3. The high-altitude cold desert of Jammu and Kashmir and Himachal Pradesh.
Desert fauna in India is also quite diverse, with about 1200 sp. of animals reported from Thar region of which 440 are vertebrates and 755 are invertebrates. Desert fox, Desert cat, Houbara Bustard and some Sandgrouse species are restricted to the Thar area (Rodgers and Pawar 1988). In the remote part of Great Rann, Gujarat lies the nesting ground of Flamingoes and the only known population of Asiatic wild ass.

The cold deserts in India cover a vast area of 109 990 sq. Km, about 87,780 sq. km in
Laddakh (Jammu and Kashmir) and 22,210 sq. Km in Lahaul -Spiti (Himachal Pradesh). The diversity of the high altitude cold deserts has been studied only recently with many insect species being endemic.

Interestingly the cold desert harbors Kiang a close relative of the Indian wild ass found the Rann of Kachchh. Other distinctive animals include Snow leopard, Yak, Tibetan antelope, Ibex, Blue sheep, Tibetan gazelle, Woolly hare etc.

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