INDIA AS A MEGA DIVERSITY NATION

The term megadiverse country refers to any nation that harbours the majority of Earth's species and high numbers of endemic species.The UNEP (United Nations Environment Programme) has recognised 17 Megadiversity Nations across the world. India is one among them due to its commendable diversity of organisms. 

India has 4 out of 34 globally identified  Biodiversity Hotspots (Himalaya, Western Ghats, Indo-Burma, and Srinlanka- Sundaland). India has wide range of habitats- The varied edaphic, climatic and topographic conditions and years of geological stability have resulted in a wide range of ecosystems and habitats such as forests, grasslands, wetlands, deserts, and coastal and marine ecosystems. Arid, semi- arid and desert regions occupy 38.8% of India's land mass with 682 species of which 6% is endemic. This area is also rich with cat type predators- Lion, Leopard and Tiger. The Great Indian Bustard is a threatened bird living in this habitat. 

The cold Himalayan region covers 5.8% of the geographical area. The cold desert also harbors endangered species such as snow leopard, yak and Asiatic ibex.  

India has a good collection of wetland habitats as well with about 4500 square kilometers of Mangrove ecosystem. The fish and bird diversity is high in such regions.  We have 783 fresh water fishes, of which 223 are endemic. India has good fish diversity and the country is one of the largest fish producers of the world. 

India has a lengthy coastal habitat of 7500 kilometers, with diverse habitats like estuaries, lagoons, backwaters, salt marshes and coral reefs. These habitats are also rich in species diversity.

India has diverse forest habitats, consisting of 23.5% of total land mass of which 75% are located in North East states India. India has 16 major forest types. The mountain ecosystem of India consists of forest ecosystems. Western Ghats and Eastern Himalayas are rich in diversity of species with 40% of endemism. 

Considering the major categories of life forms, India has the following diversity:

Animals

1. Protists- 2577 (out of 31,200 in the world)
2. Mollusca- 5070 (out of 81,000)
3. Arthropoda - 68300 ( out of 9,90,000)
4. Fishes- 2546 (out of 30,000)
5. Amphibia- 209 (out of 6200)
6. Reptiles- 456 (out of 8200)
7. Birds- 1232 (out of 9900)
8. Mammals- 390 (out of 5490)

Plants (As per 2007 data)

1. Algae- 6500 (out of 40,000)
2. Bryophytes - 2825 (out of 17000)
3. Pteridophytes- 1200 (out of 13000)
4. Gymnosperms- 48 (out of 980)
5. Angiosperms- 18000 (out of 2,50,000)

Microbes

1. Bacteria- 850 (out of 8500)
2. Fungi- 14500 (out of 72000)
3. Virus- 1200 (out of ????? not estimated) as per 2019 data
4. Lichens - 2000 (out of 35000)

 

GRASSLAND ECOSYSTEM

Grassland is an area where the vegetation is dominated by grasses, that is members of  families Poaceae and Cyperaceae etc. The vegetation is characterized by a continuous cover of grasses. Grasslands receive up to 150 cm rainfall per year. The temperature in this region varies from 15 to 35 degree Celsius. The dry season lasts for nearly 8 months,  making it the longest phase of a grass land. The grasses dominate in this region because rain fall is not sufficient to support the growth of trees and  other larger species. 

Grasslands are mainly categorized in to two:

1) Tropical grasslands

2) Temperate grasslands

Tropical grassland

Tropical grasslands are those distributed in the tropical countries of the earth. They are popularly known as Savannah. Fire is a frequent character of this grassland. The major species of the vegetation include grasses, Acacia and palms. These grasslands are well known through various television channels such as Discovery, National Geographic and Animal Planet. This habitat provides a lot of stories of predation and survival. 

The largest of savannah is located in Africa, especially central part of the continent such as Kenya, Tanzania etc. They are also found in Brazil. In India, the Banni Grassland Reserve is located in Gujarat. The soil in savannah is porous, which promotes rapid drainage of water, therefore only a thin layer of humus is present. 

Animals occurring in the tropical grasslands include, lion, cheetah, leopard, hyena., elephant, giraffe, rhinoceros, ant eaters and African mole rats.

Temperate grassland

Temperate grasslands are those distributed in the temperate zone of the earth. The temperature in the winter falls below minus 10 degrees, while summer is very hot reaching 35 degrees. Rainfall ranges between 25 to 100 cm in a year. Fire is very frequent, often initiated by lightening and therefore tall trees are unable to sustain.

Temperate grasslands are called in different names in different countries. For example, Prairies in North America, Steppes in Russia, Pampas in Argentina and Veldt in South Africa. Prairies are grasslands with tall grasses while steppes are grasslands with short grasses. The soil is deep, dark, and nutrient rich. The rotting roots of the grasses hold the soil and prevent erosion. 

The vegetation include tall grasses such as Andropogon gerardii, Panicum, Switch grass etc. The animals include Kangaroo in Australia, Pronghorn antelope in North America, Horses in Europe, gazelles, buffaloes, saiga antelope and many smaller animals.

Importance

1. Good centers of carbon sequestration. 

2. Grasslands begin the food chain in the ecosystem.

3. Helps for domestication of many helpful animals such as buffaloes, horses, ass and cow.

4. Prevents soil erosion.