“Biodiversity” can be defined as “all life forms that occur on earth and includes species subspecies, races and populations.”
‘Biodiversity’ or ‘Biological diversity’ refers to all living organisms with their manifold variety and interaction among themselves.
Country like India with only 2.4% of the world’s land area has great habitat diversity and high species diversity. India has 45,364 species of plants (includes bacteria, algae, fungi, lichens, bryophytes and higher plants). Similarly, a total of 89,315 species of animals are known and described from India.
Of these 68,389 species (nearly 75%) belong to the phylum, Arthropoda. Robert May estimated that more than 1 lakh species of plants and 3 lakh species of animals are yet to be discovered and described from India. India has attained the status of mega-diversity nation along with eleven other countries of the world. Loss of the ‘species’ endangers our own existence and the existence of the environment in which we live. The loss of biodiversity occurs in small quantities and gradually assumes dangerous level.
Species once lost cannot be replaced. This irreversibility is most important factor which concerns us. The loss of one species threatens the existence of others. It is believed that several ancient civilizations were exterminated due to loss of biodiversity. So, survival of man is also under severe threat due to immense loss of biodiversity.
Three Levels of Bio-Diversity:
(a) Ecosystem Diversity:
It relates to varieties of ecosystems seen on this earth like; savannas, rain forests, oceans, lakes, marshes, deserts and all other environments where species evolve and live.
Ecosystem diversity is of 3 types:
α, β and γ (Whittaker, 1965).
(i) Alpha diversity (a-diversity or diversity within a community):
It is the diversity of organism, within a community i.e., the number of species in the given community or habitat.
(ii) Beta diversity (β diversity or diversity between community):
It is the diversity observed due to species composition of communities along altitudinal gradient or moisture gradient or any other environmental gradient. It occurs due to replacement of species. More dissimilarities between species there will be more beta diversity.
(iii) Gamma diversity (γ-diversity or diversity among communities):
It refers to diversity of organisms among communities in the geographical regions.
(b) Species Diversity:
It refers to the variety of living organisms present on this earth. Although only 1.7 million organisms have so far been identified, it is believed that the total number is likely to be between 10 to 50 million.
(c) Genetic Diversity:
It relates the genetic variations seen in the species which is related to shape, size, colour, flavour, disease resistance, structural and functional characters etc. Besides these, the cultural diversity is related to thousands of different cultures seen in the human society. Cultural diversity interacts with biodiversity. Agricultural practices, religious beliefs and social structures have positive or negative impacts on biodiversity.
Hot Spot of Biodiversity:
Hot spots are areas with high density of biodiversity or mega diversity.
Hot spots are generally determined based on four factors:
(i) Number of species/species diversity
(ii) Degree of endemism (species restricted to a particular area or region)
(iii) Degree of threat to the habitat due to its degradation and fragmentation
(iv) Degree of exploitation
The number of hot spots in the world is 34 covering an area less than 2% of land surface with about 20% of human population living there. There are 15 hot spots in tropical forests, 5 in mediterranean type forests and 9 in island. India has 3 hot spots – India-Burma, Himalaya and Western Ghats – Sri Lanka. India is considered as a country of mega-diversity with 2.4% of land area and having 8.1% of global diversity.
Conservation of Biodiversity:
1. From time immemorial, Indians are worshipping plants and animals and protect them from extinction.
2. Emperor Ashoka, in 3rd century B.C., had set up hospitals and reserves for wild animals and birds. It is world’s first recorded information on measures taken for conservation of biodiversity.
3. In recent years, many popular movements were taken up for preservation of biodiversity in India. For example; CHIPKO movement in Tehri-Garhwal region in 1973 by famous environmentalist, Sunderlal Bahuguna, APPIKO movement in Western Ghats in 1983 etc. worth mentioning.
4. Due to religious beliefs, large number of sacred groves is set up by people, which help in the preservation of flora and fauna.
5. In the recent times, the need for conservation of biodiversity was better understood. It helps in preservation of the entire flora and fauna, instead of identifying and conserving few threatened species from extinction.
6. Several conventions and agreements on conservation of biodiversity were taken up.
(a) In 1970, UNESCO held the first convention on “Man and Biosphere”.
(b) Ramsar convention on “Wetlands and Water fowl habitat was held in 1991.”
(c) CITES (1973) for endangered species.
(d) FAO (1983) for genetic resource matrials.
7. “Earth Summit” was held at Rio de Jeneiro (Brazil) in June 1992.
(i) 155 nations of the world signed the “Convention on Biological Diversity.”
(ii) It was ratified by India in 1994.
(iii) A Biological diversity Bill was passed by Indian parliament in 2000.
(iv) The National Biodiversity Strategy and Action Plan was launched in January 2000 by Ministry of Environment and Forest, Govt. of India.
(v) It was estimated that 90% of the world’s total biodiversity lies in Southern nations and India harbours 6.5% of world’s flora and fauna.
(vi) Due to changes in the habitat, nearly 1/3rd of the total 1.5 million species, are likely to become extinct within next few decades.
(vii) In India, conservation of Biodiversity is under serious consideration. Several Acts, Boards, Institutes and Reservers have been instituted for its preservation such as; Indian Board of Wild Life (1991), the Wile life (protection) Act, 1991, The forest (conservation) Act, 1980, Establishment of National parks, Sanctuaries, Projects for Individual animals (like : Tiger, Crocodile, Turtle etc.), Biosphere reserves etc.; National Bureau of Plant Genetic Resources, New Delhi, N.B. of Animal Genetic Resources, Karnal, N.B. of Fish Genetic Resources, Lucknow and Wild Life Institute of India etc.
An integrated approach is necessary for conserving the global biodiversity. Establishment of nature reserves, biospheres, sanctuaries will help to conserve it. An international concensus on establishing global gene bank, microbiological resource centres and marine parks should be established to conserve the biodiversity for future generations.