Phytogeographical zones of india
- 1. Phytogeographical zones of India S.Esakkiammal II M.Sc BOTANY DEPARTMENT OF PLANT SCIENCE, M.S UNIVERSITY
- 2. Phytogeography - Definitions: • Phytogeography (from Greek, phyto = "plant" and geografía = "geography" meaning also distribution) • Phytogeography is concerned with all aspects of plant distribution, from the controls on the distribution of individual species ranges to the factors that govern the composition of entire communities and floras.
- 3. • Phytogeography is defined by Good (1964) as ‘that branch of botany that deals with the spatial relationships of plants both in the present and the past’ • Phytogeographical areas are governed by the world’s climatic belts and Phytogeography is concerned with the floristics of the common pool resulting from historical factors; ecology is concerned with the segregation of species within the common pool by environmental factors (Wickens 1976). • According to D. Chattarjee (1962) A phytogeographical region is defined as an area of uniform climatic conditions and having a distinctly recognisable type of vegetation
- 4. Distribution of plants is mainly controlled by climatic factors. • Temperature, Altitude, Precipitation, Atm moisture, Light intensity and duration. • Type of soil. • Biotic factors play an important role in distribution and establishment of species. • The great area of Indian subcontinent has wide range of climate and corresponding diversity in the vegetation.
- 5. India has been divided into the following botanical zones by D. Chatterjee (1962) • (1) Western Himalayas, • (2) Eastern Himalayas, • (3) Indus plain, • (4) Gangetic plain, • (5) Central India, • (6) Deccan, • (7) Western coasts of Malabar, • (8) Assam, and • (9) Bay Islands of Andaman and Nicobar.
- 6. Flora of Western Himalaya: • This region comprises north and south Kashmir, part of Punjab and Kumaon region of Uttaranchal. • Average annual rainfall in the region is 100- 200 cm. The region is wet in outer southern ranges and slightly dry in the inner areas. • At high altitudes, snowfall occurs during winters. The region is subdivided into three zones.
- 7. • Salmalia malbaricum • Shorea robusta • Butea monosperma.
- 8. • Dalbergia sisso • Ficus glomeruta • Eugenia species
- 9. Submontane (lower, tropical and subtropical) zone: • This zone includes outer Himalayas i.e. regions of Siwalik Hills and adjoining areas from 300 to 1500 m altitude. • Average annual rainfall of the zone is around 100 cm. • The vegetation consists of subtropical dry evergreen, subtropical pine and tropical moist deciduous forests.
- 10. Temperate (montane) zone: • This zone extends in the western Himalayas between the altitudes 1500 and 3500 m. • The climate is wet between the altitudes 1500 and 1800 m and is drier at higher altitude. • The vegetation consists of wet forests, Himalayan moist and Himalayan dry temperate forests.
- 11. Alpine zone: • This zone extends between 3500 m and 5000 m altitudes. • The rainfall is very scanty and climate is very cool and dry. • The vegetation consists of alpine forests.
- 12. • The vegetation of this region consists of chiefly Acacia modesta, Euphorbia royleana, Olea, Bombax ceiba, Themada, Chrysopogon serrulatus, Bauhinia vahlii, Shorea robusta, Cassia fistula, Lagerstroemia parviflora, Murraya keonigii, Zanthoxylum alatum, Terminalia, Anogeissus latifolia, Toona ciliata, Zanthoxylum alatum, Adhatoda, Carissa, Rosa, Rubus, Syzygium, Crataegus, Diospyros, Emblica, Picea, Pinus wallichiana, Cedrus deodara, Rhamnus, Salix, Berberis, Smilax, Arundinaria, Fraxinus, Fragaria, Viola, Artemesia, Rheum, Sedum, Betula, Anemone, Saxifraga, Geranium, etc.
- 13. Flora of Eastern Himalayas: • Eastern Himalayas comprises of mountain ranges from Sikkim to Arunachal. • The climate is warmer and wetter than in western Himalayas. • Tree line and snow line are higher by about 300 m than in the western Himalayas. • It is botanically best known part of this region. More than 4,000 sp. of phanerogams belonging to 160 families and lower plants are found in this region.
- 14. • Terminelia • Stericulia • Anthocephalus cadamba • Bauhinia
- 15. • Michelia champaka • Cinnamomum sp. • Eugenia sp.
- 16. • Abies sp. • Juniperous • Tsuga sp.
- 18. This region is also divided into three zones. • Submontane (lower, tropical and subtropical) zone: This zone extends from the foothills up to the 1850 m altitude. The climate is nearly tropical and subtropical. The vegetation consists of subtropical broad-leaved forests, pine forests and wet temperate forests. • Temperate (montane) zone: The zone extends from 1850 m to 4000 m altitude, about 500 m higher than in the western Himalayas. The vegetation consists of typical temperate forests with oaks and Rhododendron at lower and conifers at higher altitudes. • Alpine zone: This zone extends from 4000-5000 m altitude. The climate is very cool and dry. The vegetation consists of alpine forests.
- 19. Flora of Indus Plain: • The area comprises of Gujarat, Delhi, Rajasthan, Haryana and Punjab. • It is the dry region from plains to Mt. Abu; deserts and irrigated lands. Rainfall is very low in extremely dry areas. • The climate has very dry and hot summers alternating with dry and cold winters. • The annual rainfall is generally less than 70 cm and may be 10-15 cm in some areas. • Most of the region is desert today though it had dense forests about 2000 years ago that were destroyed due to biotic factors particularly extensive cattle grazing. • The vegetation today consists of tropical thorn forests and grasslands in some areas.
- 20. • Indus plain can be divided into 3 types of vegetation as tropical dry deciduous, tropical thorny and dry shrubs.
- 21. • Acacia arabica • Prosopis sp. • Salvodora sp. • Zizyphus zuzuba • Mangifera sp.
- 22. Flora of Gangetic Plain: • The area extends from east Delhi to Sundarbans of Bengal passing through Bihar, Orissa and U.P. It includes dry deciduous (Scrub) and Moist deciduous vegetation. Sometimes the Indus region and Gangetic region, because of similar type of vegetation, is called as Indo Gangetic plain. • Average annual rainfall ranges from 50 cm to 150 cm from east to west. • The Gangetic plain divided into upper Gangetic plain, Lower Gangetic plain and Sundarbans.
- 23. • Dry deciduous forests are common • Capparis, Dalbergia, Acacia species are very common.
- 24. Lower Gangetic plain: • The vegetation is dominated by Shorea robusta, Artocarpus, Lagerstroemia, Ptersopermum, Bombax, Ehertia, Adhatoda, Murraya koenigii, Pogosternon, Aegle marmelos, Holoptelea, Areca, Borassus, Pagostemon etc.
- 25. Upper Gangetic plain: • The vegetation is dominated by Acacia nilotica, Balanites, Jatropha, Flacourtia, Capparis decidua, Butea monosperma, Madhuca, Zizyphus, Dalbergia, Phoenix, Nyctanthes, Woodfordia, Adhatoda, Terminalia, Prosopis, Tinospora, Vitis, Cocculus, Ixora, Carissa, Hemidesmus and many types of grass.
- 26. Sunderbans • The largest mangrove forest of the world is of sunderbans covering and area of over 15,000 sq. km. • The area has sea creepers and swampy islands. • The main vegetation includes Typha elephantine (elephant grass), Pharagmites karka (reed), Pandanus, Alpina, Ipomoea biloba, Bruguiera con ugata, Kandelia. candel, Heritiera, Ceriops, Aviecnnia officinalis, Aegiceras, Sonneratia, Nipa fruiticons, Pheonix paludosa, Cocos nucifera, Rhizophora mucronata, Acanthus illicifolius, Panicum repens, Sueda maritima, Salicornia, Allophylus, Tamarix, Hygrophila, Derris etc.
- 27. Central India • This region comprises part of Orissa, Madhya Pradesh, Vindhyan region and Gujrat. • The areas are mostly hilly with some places at 500-700 m altitude. • The average annual rainfall is 100- 170 cm. • Biotic disturbances are very common in this region resulting in degradation of forests into thorny forests in the open area. • The vegetation consists of tropical moist deciduous forests, chiefly Sal forests in areas of annual rainfall above 150 cm and mixed deciduous forest in areas of 125-150 cm annual rainfall. Tropical thorn forests are found in the areas of annual rainfall below 125 cm.
- 28. Flora of Deccan: • Deccan includes entire peninsula South of Ganges and east of Malabar. • The region comprises southern Peninsular India from southern Madhya Pradesh up to Kanyakumari excluding the Western Ghats. • The average annual rainfall in the region is about 100 cm. • The vegetation consists of tropical dry evergreen, dry deciduous and swamp forests. • The important trees are Michelia champaca, Dillenia aurea, Chloroxylon swetenia, Cedrela toona, Santalum album, Pterocarpus sentalinus, Soyamida, and tree ferns etc.
- 29. • Deccan is characterized by presence of “black cotton soil”. Common planes of this soil are Hibiscus, Cassia auriculata, Acacia arabica, Parkinsonia aculeata, Calotropis procera, Zizyphus numularia, Jatropha grandiflora etc. • The vegetation of Coromandal subregion is same in Deccan except some estuarial and mangrove plants such as Brugiera, Ceriops, Avicinnia etc. Other plants are Mimusops, Garciia, Chloroxylon swietenia, Strychnos nux-vomica etc.
- 30. Flora of Malabar: • Area of Malabar includes Kerala, Maharashtra, Gujarat and Karnataka. Hill areas of western ghats are also included in this zone. • Generally, the plants are distributed into: (a) Temperate evergreen forests, (b) Subtropical evergreen forests, (c) Tropical evergreen forests, (d) Tropical semi- evergreen forests, (e) Tropical deciduous forests, and (f) Mangrove forests.
- 31. Flora of Assam: • The area includes Valleys of Brahmputra, Jaintia, Khasi and Garo hills, Mishmi hills, North Himalayas, Santosh River, Naga, Cachar and Mizo hills, Mizoram, Meghalaya, Nagaland, Manipur, Tripura and Assam region. • Good rainfall, dense vegetation is characteristic of this area. • The vegetation is richest in the world except Khasi hills region. • The vegetation consists of tropical evergreen and wet temperate forests in the lower plains while hilly tracts up to 1700 m altitude have subtropical pine forests
- 32. Assam
- 33. Andman and Nicobar • This region includes Andman and Nicobar Islands. The climate of the region is warm and humid with very high temperature and annual rainfall. The vegetation consists of littoral mangrove, evergreen, semi- evergreen and deciduous forests.