This article throws light upon the top eleven types of biomes that exist in India. They are: 1. Tropical Rain Forest Biome 2. Tropical Deciduous Forest Biome 3. Temperate Forest Biome 4. Boreal Coniferous Forest Biome 5. Temperate Grassland Biome 6. Tundra Biomes 7. Temperate and Tropical Desert Biomes 8. Tropical Savanna and Grassland Biomes 9. Wetland Biomes 10. Freshwater Biomes 11. Marine Biome.
Type # 1. Tropical Rain Forest Biome:
In warm and wet climates of the tropics, this biome exits with most majestic and dense vegetation.
Species diversity and richness of life forms are maximum in this biome.
The species diversity is so high that often difficult to find two individuals of same species in close vicinity.
There are lots of full trees with epiphytic growth of mosses, ferns and orchids. The litter fall and their decomposition rate is very high in the forest. The forest is multitier with dense canopy cover.
Tropical rain forests are common in equatorial belt in Indonesia, Malaysia, Singapore, Hawaii, Amazonia, and also in Central Africa particularly in Zaire basin region. In India, the rainforests are confined to North-East in Assam, Meghalaya, Arunachal Pradesh, Mizoram and Manipur. Similarly rainforest also exits in South Western region of India, like Karnataka, Tamil Nadu and Kerala.
Over the years of extensive deforestation in tropics, the rainforest area rapidly disappeared and slowly converted into agricultural land. Rainforest is a natural forest which could not recover by man’s manipulation. Thus there is a great need for conservation of rainforest rather than creation of rainforest.
Type # 2. Tropical Deciduous Forest Biome:
In tropics, deciduous forest is very much prominent component, where forest shed their leaves before winter onset. New flush of leaves appear after 2-3 months. These forests are not so dense as that of rainforest. There are places, where the deciduous forest may be dry and thorny.
In India, deciduous forest biome is very much predominant in various parts. Tropical sal forest or sal with other deciduous species is quite common. Ground cover vegetation in deciduous forest is very significant.
Type # 3. Temperate Forest Biome:
In mid-altitude of mountains temperate forest biome exits. It extends up to tree line of upper elevation. In temperate region mostly broad leaved evergreen forest or needle leaved coniferous forest or a mixture of species prevailed. The climate have high humidity and thus having epiphytes, mosses, ferns and other lower groups of plants.
In Himalayas, the rich biodiversity is prevailed in temperate biomes. There are a good number of endemic species of various groups which prevail in this region. In many countries, plantation cups were introduced in temperate climate by removing natural forest cover and there by destroying the rich endemic germplasm.
Type # 4. Boreal Coniferous Forest Biome:
This is a specialised temperate coniferous forest biome found in high mountains of Canada and Alaska. The plant community have low statured forests mostly coniferous species with ectomycorrhizae in the roots. Soil is somewhat acidic (4.5 to 5.0 pH) due to decomposition of needle leave litter. Often these forest also called Taiga. Forest floor have swamps and pit bogs.
Type # 5. Temperate Grassland Biome:
It is well known that grasslands are the most extensive formations of vegetation types found all over the world and in all ranges of climates from mesic to xeric and from cold to warm conditions. The temperate grasslands are however extensive in the North America and are called as prairies.
They may be tall grass prairie, mid grass prairie and short grass prairie depending upon the height of the herbage portion. In many countries, the natural grassland is largely converted to grazing land or croplands. The temperate grassland is dominated by graminoids followed by sedges and forbs or the non-graminoids like dicot weeds.
Type # 6. Tundra Biomes:
These are extremely cold condition with alpine or subalpine habitats. Only herbs and dwarf shrubs are grown along with mosses, lichens and creepers. Because of extreme cold, the soil moisture is frozen at a depth of few centimeter from the top. This is called permafrost.
There are two kinds of tundra “Arctic tundra” in the extreme northern latitudes (north of 60ON latitudes) and alpine tundra on mountain tops even at lesser latitudes. The regions is snow covered for sometime in a year. Soils are rich in organic matter because of very slow decomposition rate.
Type # 7. Temperate and Tropical Desert Biomes:
These are two kinds of desert habitats cold desert and warm or hot desert. Rainfall is very scanty (less than 500 mm per annum) in hot desert, while frost and snow are common in cold desert. Cold desert often noticed in temperate to subalpine region, with grasses and succulents, where as hot desert found in tropics where thorny forest, scrubs and succulents are grown.
West Indian desert which is a part of Thar desert is very well known hot desert, while in the Siberian region cold desert prevails.
Type # 8. Tropical Savanna and Grassland Biomes:
In an estimate it is reported that grass covered biomes constitute about 42.57% area in Africa, 6-12% in Asia, over 50% in Australia and about 80% in South America. In tropics, the grasslands which is often called savanna are rich in grasses and sages interspersed by some shrubs and trees. But there are dried places where tall grasses dominate in ravine land with scattered trees.
Moreover the grassland of various countries are named in different ways:
In Central India, the tropical grassland constitute about four distinct associations viz.,:
(i) Schima- Dichanthium type,
(ii) Dichanthium-Cenchrus— Lasiurus type,
(iii) Phagaguitics—Saccharum—lmperata type and
(iv) Themeda-Arundinella type.
Type # 9. Wetland Biomes:
Wetland habitat constitutes the transition zone between terrestrial habitats and deep water bodies. These includes, swamps, paddy fields, riverine flood plain, lakes, coastal swamps and so on. These habitats support specialized vegetation cover with characteristic fauna and serve as the breeding grounds of many migratory birds.
These habitats constitute wetland biomes. In tropics wetland biome have rich flora and fauna. In many place such unique habitats are transformed for various man made activities and thus many species of flora and fauna became extinct from the native region.
Type # 10. Freshwater Biomes:
Freshwater biomes include open water systems such as lakes and rivers and as water-logged regions known as bogs, marshes and swamps. Bogs consists of impervious substrates where rainfall is high. They are dominated by the growing plants able to tolerate waterlogged and nutrient-poor conditions such as Sphagnum moss and insectivorous sundews.
Swamps are tree-dominated wetlands occurring in tropical, subtropical and temperate regions.
Freshwater contains dissolved gases, nutrients, trace metals and organic compounds as well as organic and inorganic particles. These chemical carbonate from rainwater which washes substances out of the atmospheric dust deposition and from the leaching of soils and rocks from the surrounding catchment areas.
Streams and rivers differ greatly, depending on their size. They also vary in their length from their source in upland areas to their mouth where the river meets the sea.
In general as the mouth of a river is approached:
(i) The speed of water flow decreases, the water becomes less turbulent and oxygen levels fall;
(ii) The volume of water increases having accumulated as the river passes through its catchment;
(iii) The energy of the river decreases, suspended material is deposited and the river bed becomes composed of finer particles and eventually silts;
(iv) The river bed becomes less steep because the larger volume of water erodes a broader channel;
(v) Human influences increase; many rivers flow through farmland and urban or industrial areas and receive agricultural run-off, treated sewage and other effluent which may raise the organic content of the river leading to eutrophication.
Streams are high in the catchment that are non-polluted, support caddis fly (Trichoptera) and blackfly (Simulium spp.) larvae feeding on fine organic particles. The water will be too turbulent and nuitrient poor for all but aquatic mosses, liverworts and algae.
Plankton communities, consisting of algae, photosynthetic bacteria, crustaceans and rotifers, can develop further downstream where the volume of moving water is increased and the current is reduced. Fish, reptiles, birds and mammals may be present.
As water flow continues to decrease, particularly at the edges of a growing channel, plankton communities become more complex and sediment is deposited, providing a roodng medium for larger aquatic plants (macrophytes) and a habitat for benthic organisms such as oligochaete worms, chironomid larvae and molluses.
Emergent plants, which grow up beyond the water’s surface provide physical habitat for invertebrates, fish and epiphytic algae, which in turn provide food for other orgamisms.
Type # 11. Marine Biome:
This is largest biomes of the world. It covers high saline coastal area to open sea area. In polar region it is mostly snow covered. The coastal shallow marine biomes are highly productive and divisible into tidal neitric and the continental shelfs. Away from the coast are the oceanic belts with upper surface euphotic zone (up to 200 m) and lower battyal (200 m to 2000 m deep) and bottom abyssal dark deep zone.
Life is abundant in euphotic zone. Marine biome is the principal food source of mankind today and tomorrow.
In marine environment huge deposit of petroleum, natural gases and minerals are recorded. But exploration of such resources leads to destruction of marine biome. Over the year, ocean is used as a dumping ground of hazardous substances of diverse categories.
Such activities are noted and regulated by strong international vigilance. Marine pollution for all sources needs to be curbed for protecting marine biomes, i.e. resources for 21st century.
The major climatic zones are depicted in Fig. 5.1.