India is situated on the middle of “Afro tropical, Euro- Asian and Indo Malayan region”. India is one of the 12 mega biodiversity country of world. The 12 mega diversity region of world are Mexico, Coulombia, Medagaskar, Ikwador, Cameroon, Peru, Brazil, Jaira, China, Malaysia, Indonesia and India. India represents 62% endemic species. Most of these spots are located in the tropics:
(i) Brazil represents 1/5 of World biodiversity with 50,000 plant species, 5,000 vertebrates, 10 – 15 million insects and millions of micro organism.
(ii) India is said to represent 8% of the recorded species with 47000 plant species and 81000 animals.
The country is divided into 10 bio-geographical regions:
Trans-Himalayan, Indian desert, Semi arid, Western Ghats, Deccan Peninsula, Gangetic plains, NF India, Island and Costs. Clarks (1898) recognized 11 botanical regions from India while Hooker 1909 divided into 9. Chatterjee 1939 into 10 and Razi 1955 in 21 regions
The Indian sub continent is characterized with a variety of climate type and flora of the country in also correspondingly of different types in its different parts. The country has been divided into following nine floristic (Botanical) regions:
1. Western Himalaya:
Kumaun to Kashmir with an annual rainfall of 200 cm. Altitudinal these are following three zones of vegetation corresponding to three climatic belts.
(i) Sub montane Zone:
This extends upto 1500 metres altitude and comprises mostly of Siwalik ranges. The forests are tropical and subtropical having trees like Shorea robusta, Dalbergia sissoo, Cedrela toona, Ficus glomerata, Eugenia jambolana, Acacia catechu, Butea monospema (dhak), Zizyphus and thorny succulent euphorbias on slopes.
(ii) Temperate Zone:
Above submontane zone extend montane temperate forests upto 3500 m. They are dominated by plant species like Quercus, Acer, Ulmus, Rhododendron, Betula, Salix, Cornus, Populus, Pinus, Cedrus, Picea and Taxus.
(iii) Alpine Zone:
Between 3500 – 4500 m and characterized by alpine forest vegetation with scrub and meadow e.g. Abies, Betula, Junipers, Rhododendrons.
2. Eastern Himalaya:
It includes regions of Sikkim and NEFA and is characterized by more rainfall, less snow and high temperature. This is divided into 3 zones.
(i) Tropical zone:
Up to 1800 m, this zone has tropical semi-evergreen or moist deciduous forest. These forests comprise the plants Shorea robusta, Acacia catechu, Dalbergia sissoo, Terminalia, Albizia, Dendrocalamus etc.
(ii) Temperate zone:
1800 m – 3800 m and has typical montane temperature forests like oaks, Michelia, Quercus, Pyrus, Synplocos, Eugenia and Conifers like Juniperus, Cryptomeria, Abies, Pinus, Larix, Tsuga, Salix, Rhododerdron, Arundinaria.
(iii) Alpine zone:
Beyond the temperate zone extends alpine zone up to 5000 m. e.g. Juniperus, Rhododendron.
3. Indus plain:
Arid and semi arid zone of Punjab, Rajasthan, Kutch, Gujarat and Delhi. The rainfall is less than 70 cm. The vegetation is tropical thorny forest in semi arid zone and typically desert in the arid region as Xerophytic e.g. Acacia nilotica, Salvadora, Capparis.. Zizypus, Calotropis, Saccharum, Euphorbia.
4. Gangetic Plains:
Uttar Pradesh, Bihar, Bengal and part of Orissa and is characterized by moderate amount of rainfall and most fertile (alluvial) soils. Vegetation is chiefly tropical moist and deciduous and dry deciduous forest type.
The common plants of this zone are Dalbergia sissoo, Acacia nilotica, Saccharum munja, Terminalia arjuna, Acacia catechu (Khair), Azadirachta indica (Neem), Ficus religiosa (Pipal), and weeds, grasses like Xanthium, Argemone, Amaranthus. In Gangetic delta (Bengal south) mangrove vegetation is common.
5. Central India:
It comprises Madhya Pradesh, parts of Orissa and Gujarat. The rainfall is 150 – 200 cm. and its vegetation is thorny, mixed deciduous and teak type. The chief plants are Tectona grandis, Madhuca, Butea, Dalbergia, Terminalia, Zizypus, Acacia, Mangifera etc.
6. Malabar (West Coast):
This region include western coast of India from Gujarat to comorin with heavy rainfall. The forests are tropical evergreen in extreme west, semi evergreen towards interior subtropical or montane temperate evergreen forests in Nilgiris and mangroves near Bombay and Kerala Coast.
7. Deccan Plateau:
This region extends all over Peninsular India (Andhra Pradesh, Tamil Nadu and Karnataka) and has rainfall up to 100 cm. Its central hilly plateau has tropical dry deciduous forests of Bowsellia scrrata, Tectona grandis while the low eastern dry coromondal coast has tropical dry evergreen forests of Santatum albums, Cedrela toona, e.g. Acacia, Prosopsis, Euphorbia, Capparis, Phyllanthus etc.
This region is characterized by heavy rainfall (200 to 1000 cm). The vegetation is either dense evergreen forests or subtropical. The evergreen forests include trees like Dipterocarpus macrocarpa, Shorea robusta, Ficus elastica etc grasses like Saccharum sp. Themeda sp.
Insectivorous plants as Nepenthes sp. and also Epiplytes (ferns and orchids). In the northern cooler region wet hill forests include plants like Alnus, Betula, Rhododendron, Magnolia etc.
Mangrove and beech forest at its coasts and evergreen forests of tall trees in the interior. Important plant species of this island are Rhizophara, Calophyllum Lagerostroemia etc.
Forest and Wild Life Institute of India divided India into 10 zoo-geographical regions:-
Ladhak (J & K) and Himanchal Pradesh (Lahul) total area 1, 86,200 sq. km. at a height of 4500 – 6000 m. The species are Tibetan Ass, Wild Yak, and Palas Cat etc.
2. Himalaya North Eastern, Western, Central and Eastern:
In Himalaya at a medium height and covered 2, 36,300 sq. km with 56 protected area and represent endangered species.
3. Desert (Kutch – Gujrat Thar Rajasthan):
Represent very sensitive ecosystem and covered 2, 50,000 sq. km. and 89 sq. km is protected. It represents Wild ass, desert cat, fox, sauns bird and hanshabar (duck).
4. Semi Arid Zone:
Represent Punjab, Gujarat, Rajasthan, spread among 5,08,000 sq. km. Sariska and Ranthombore reserve park is situated on them with 11675 sq. km. as safe and 52 protected areas. Gir lion is famous all over the world.
5. Western Ghat and Coastal Plain:
Maharashtra, Kerala, Karnataka represents 1, 59,000 sq. km. with 15955 sq. km. as protected area and 44 parks/, sanctuary.
6. Deccan Peninsula :
Deccan plateau, South Central part, North Eastern part, Chota Nagpur and Central high lands represents 43% of Indian land (14, 21,000 sq. km.). 115 protected parks/ sanctuary are spread on 4610 sq. km. with many animals.
7. Gangetic Plain:
Spread over 3, 59,400 sq. km. and represent 25 protected sites. This is an agriculture site.
8. Marine Coasts:
Represent Eastern & Western Coast, Sunder bans sanctuaries of (Leopard) is situated on this area with highest number of leopard in India.
9. North East Zone:
Brahmaputra valley and Assam. Represent high biodiversity zone in 1880 sq. km. 17 protected areas are situated.
10. Indian Islands (Andaman, Nicobar & Lakshadweep):
384 islands represents 225 animal’s species, out of this 50% are endemic. 101 protected areas on 708 sq. km.