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.

DESERT ECOSYSTEM

Desert is a terrestrial ecosystem which receives very little, lesser than 25cm per year, rainfall or precipitation. Deserts cover as much as one fifth of the earth's land surface and forms one of the major ecosystems on earth. 

Examples : Namib desert, South Africa. 

                    Atacama desert, South America

                    Sahara desert, Africa

                    Thar desert, India - Pakistan

The word comes from a Latin word desertum which means 'to abandon'.

Desertification is an ongoing process, though we don't realize it on a real time basis. We can sense the rise in atmospheric temperature, lack of rain etc., which will gradually lead to the formation of new deserts. Ancient civilizations of Greece, Mesopotamian and Mayan were demolished by the process of desertification.

Life is difficult in desert habitats, challenged with dehydration, lack of drinking water, extreme heat and sweat, lack of biodiversity which leads to lack of food material etc. Many of the organisms which survive on the deserts have specific adaptations for its survival. The camel has a bump on its back for storage of fat (NOT WATER) and they can live many days without eating anything. Their nose is adapted to prevent sand entering while sand storms. webbed feet to prevent sinking in to the sand and long eye lashes for preventing sand entering eyes.

Deserts can be classified in to two types;

1) Hot Deserts

2) Cold Deserts

Hot Deserts

Hot deserts are places with very high temperature as high as 50 degree Celsius in the day and freezing cool in the night. The soils are nutrient poor. They are found around latitude 20-30 degrees north and south of the equator. They occupy nearly 20% of the earth's surface. 

Exaples include Sahara, Atacama of Chile, Kalahari of Africa and Simpson of Australia.

The plants of the hot desert include succulents such as cactus, annuals, desert shrubs such as Fonquieria splendens. The cactus can store water. Many plants have volatile chemicals to prevent herbivores.

Animals include ants, birds, rodents, lizards, snakes, small mammals etc. Examples - Horned viper, Addax antelope, Ostrich, Camel, Golden Jackal etc.

Cold Deserts

The day time temperature in cold deserts can be around 2-4 degree Celsius, though it can raise upto 26 degrees in summer. In winter, the temperature is as low as minus 26 degrees. Precipitation is less than 25 cm per year. They show the formation of ice coated regions during winter. 

Examples-  Gobi desert, Mongolia; Great basin desert, North America; Patagonian desert, Argentina.

Succulents are absent in cold deserts, as they are susceptible to freezing. Many species have spines and shed leaves. Examples- Artemesia, Sagebrush etc

Animals live in burrows to escape the cold weather. Examples- Jack rabbit, Pocket mice, Kit fox and Coyote.

Importance

1. Deserts account for one sixth of world's population.

2. They cover one fifth of land mass.

3. Formation of minerals via dehydration- example Gypsum, borates, nitrates.

4. Carbon sequestration- The cyanobacteria in deserts store CO2 from air.

ETHNOBOTANICAL ASPECTS OF PLANTS- RAUVOLFIA SERPENTINA

Rauvolfia serpentina, known in multiple common names- Sarpagandhi, Sarpagandha, Indian Snakeroot, Devil Pepper etc- is one of the ancient plant widely used by humans since ages. 

Scientific Name: Rauvolfia serpentina (L.) Benth. ex Kurz.

Family: Apocynaceae

Habitat: Moist shady places near forests of India, Srilanka and Indonesia. 

There are nearly 100 species of  the genus Rauvolfia, a member of the milkweed family Apocynaceae. These plants are characterised by the presence of milky latex in stem and leaves. 

Morphology: The plants are sub-shrubs, with watery latex. Simple leaves with whorled (3-4 leaves) phyllotaxy. Cymose inflorescence. Petals white and fruits are crimson red.

Uses: 

The plant is widely used in modern medicine, ayurvedic, unani  and folk medicine as well. 

1. It is used in treating hypertension, eg. BP Care & Cure made by German's company.

2. It is used for insomnia, i.e., is lack of sleep. 

3. Used for central nervous system diseases.

4. Used as a tranquilizer, in case of anxiety related issues, for example Alprazolam tablets and Zolfresh tablets.

5. Root extract is used for intestinal disorders, such as dysentery and diarrhea. 

6. Used in treating hysteria and schizophrenia. 

Constituents:

The constituent is Reserpine. In addition, a lot of other secondary metabolites are present in Rauvolfia- Ajmalicine, Ajamaline, Chandrine, Renoxidine, Serpentine and tetraphyllicine. 

ETHNOMEDICINAL PLANTS- INDIGOFERA TICTORIA നീലയമരി

Indigofera , belonging to family Fabaceae, is a popular plant used by humans since ages for extraction of the blue dye Indigo. The plant is believed to be used in Egyptian mummies before 4000 years.   The dye is obtained from its leaves. 

Morphology: Indigo is an erect, profusely branched herb which grows up to 2 meters. Leaves are pinnately compound, 9-13 leaflets opposite, elliptic, base and apex rounded. Inflorescence is raceme, flowers reddish, standard, wing and keel petals present, fruit is a pod, maximum 12 seeds are found in a pod.

Habitat: Widely cultivated.

Uses:

1. Main source of Indigo dye, which is called 'King of dyes'

2. It is used aa green manure in coffee plantations.

3. It is used as tooth brush.

4. Leaf extract is used to cure burns and wounds of horses, cattle and sheep.

5. Root is used for tooth ache.

6. Antidote for snake bite, scorpion bite etc.

7. Tanzanians use it for syphilis and gonorrhoea. 

ETHNOBOTANICAL ASPECTS OF PLANTS- PONGAMIA PINNATA

Pongamia pinnata, also known as Indian beech tree or Pongam oil tree, is commonly seen in mangrove forests and deciduous forests of the Indo-Malayan region. It is a fast growing medium sized tree which is evergreen by nature. In Malayalam, it is called 'Ungu'. 

Morphology: Evergreen trees reaching up to 20 meter height. Leaves are imparipinnate, alternate arrangement, 5-7 leaflets are present, pubescent, ovate, acuminate apex, leaf margin entire, calyx 5, petals 5, stamens 10, monadelphous, ovary inferior with single chamber, fruit is a pod, reniform seeds.

Habitat: Deciduous and mangrove forests.

Uses:

1. Potential source of biodiesel.

2. Traditional medicine for bronchitis, whooping cough and rheumatism.

3. Used in itches and skin diseases.

4. Bark used for piles when bleeding.

5. Used as remedy for diabetes.

6. Roots used for cleaning gum and ulcer.