Biodiversity
Biodiversity means the variability among living organisms from all sources including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part, this includes diversity within species, between species and of ecosystem (Convention on biological diversity, UNEP, 1992).
However, according to Global Biodiversity Strategy, WRI, IUCN & UNEP (1992) it is the totality of genes, species and ecosystem in region. Ambasht et al. (1994) states that Biodiversity is manifested at all levels of organisation, from cell to ecosystem and refers to variability of all kinds of living organisms inhabiting terrestrial, marine and fresh water ecosystem or in atmosphere.
While Hosetti (2002) described it as the library of life, which means a variety of all genes, species and ecosystems that are found on our planet. It includes all the species of microorganisms, plants and animals living in water, land and air.
Biodiversity in India
India has tremendous biodiversity, genetic as well as of species and ecosystems, with different types of habitat ranging from rain forests of north east to hot deserts of Rajasthan, it lies at the junction of three biogeographical provinces of Africa, temperate Eurasia and Oriental, as a result, it has biological heritage that qualifies it as one of the twelve (12) mega biodiversity nations of the world (Kothari, 1994).
India is seventh largest country in the world and Asia’s second largest nation with an area of 32, 87,263 sq. Km (Puri, 1994).
More than 45,000 species of plants and 65000 species of animals have been recorded from the Indian subcontinent representing about 7% and 6.5% of the world’s flora and fauna respectively (Hosetti and Caplan, 2001).
According to Agrawal (2002), there are about 372 species of mammals, 1228 species of birds, 446 species of reptiles, 204 species of amphibians, 2546 species of fishes and a large number of invertebrate.
Benefits of biodiversity
Biodiversity gives us a framework for managing renewable natural resources, whether it is in view of conserving biodiversity or putting terrestrial or aquatic resources to use. In our daily lives, we are in contact with and choose different levels of biodiversity as regards our food, leisure activities and work (Kour, 2001).
It plays a number of vital environmental and developmental roles that are not accorded economic value but are crucial to human future (Khan, 1998).
Birds are most useful to humans as destroyers of harmful insects and as consumers of weed seeds. Predatory birds such as hawk, eagle, and owl are essential because they keep down the populations of rats, mice, and other rodents that would otherwise devour valuable food crops. They also pollinate many species of flowering plants. Seeds that pass undigested through the bodies of birds fall to the ground and introduce plants into new areas. The feathers of the ostrich, pheasant, goose, and other species are used for decoration. Eiderdown, duck, goose and chicken feathers are used to stuff pillows, quilts, and outdoor clothing. As per Anthes (2010) Turkeys may turn out to be a great research model for cancer.
One of the most interesting aspects of biodiversity is the way in which it collectively provides us with “Free Services”. In Chesapeake Bay (US) the Oyster plays a very crucial role in water purification. Today, the Oyster population of Bay filters a volume of water equal to that of the entire bay about once a year. Before various factors, most human driven, led to the decline of the Oyster population, it filtered a volume equal to the entire bay about once a week (Lovejoy, 1994).
Domestication of Wild mammals has helped to provide a source of protein for ever-increasing human populations and provided means of transportation and heavy work as well. Today, domesticated strains of the house mouse, European rabbit, guinea pig, hamster, gerbil, and other species provide much-needed laboratory subjects for the study of human-related physiology, psychology, and a variety of diseases from dental caries to cancer.
Wild mammals are a major source of food in some parts of the world.
A South American Pit Viper might seem to be of little relevance to people living in other areas, yet studies on venom of these vipers lead to the discovery of the Angiotensin system that regulates blood pressure in human beings. Once that system was known it became possible to drive a molecule that alters blood pressure and is preferred prescription drug for hypertension.
Threats to biodiversity
Human activities are causing major impacts on natural environments at local and global scales, producing changes to the number, identity and relative density of species in assemblages (Vitousek et al., 1997; Tilman and Lehman, 2001).
These human activities threaten the existence of many organisms by destroying their habitat or directly affecting their survival and reproduction success (Green and Hirons, 1991) and lead to many types of environmental changes which influence the processes that can both augment or erode diversity (Sagar et al., 2003).
Mankind has always used and ultimately has become widely dependent on various aspects of diversity. For millennia the balance between human and other biota was sustainable, for although there is evidence of some human induced extension in times long past the impact of people on the environment had only rather limited irreversible effects. That however, has changed in 20th century as a result of a combination and interaction of industrialisation, rising living standards, consumption impacts and even increasing human population. As a consequence, biodiversity began to be lost as our utilisation of genetic and other resources was no longer sustainable and species began to disappear at rates estimated to be up to 50 species per day (Myer, 1993).
One of the greatest threats to species biodiversity and ecosystem function may result from the high density and rapid growth of the human population (Wakermagel et al., 2002 and Rosser and Mainka, 2002).
The growth and expansion of pre-human and human populations has long displaced other species and led to their extinction, starting in the Pliocene and accelerating in the Holocene (Klein, 2000, Alroy, 2001 and McKee, 2001, 2003).
Demographic and social changes place more people in direct contact with wildlife, as human population grows, settlements expand into and around protected areas as well as in urban and sub-urban areas (IUCN, World Park Congress, 2003).
Forests are vanishing at the rate of 17 million ha/year an area about half the size of Finland and population is being added at the rate of 92 million people roughly equal to adding another Mexico each year (Postel, 1992).
At least 10% of 1, 34,000 species of plants and animals are threatened with extinction and a few have already vanished for ever (Kothari, 2001).
In spite of the fact that India is one of the mega biodiversity centres of the world, there have been recorded a decrease in the number of species. Some of the species have already become extinct; some are endangered while some others are vulnerable.
Not only in India, but all over the world there has been a drastic decline of wild life species. At present some 3956 species are endangered, 3647 species are vulnerable and 7,240 are considered rare (Wilson, 1988).
There are four main threats for drastic decline of wildlife such as:
1. Habitat loss or habitat modification by deforestation, urbanization and agricultural development etc.
2. Over exploitation for food and commercial purposes.
3. Pollution caused by pesticides, radioactive wastes and wastes from industry.
4. Introduction of exotic species, which threatened the natural flora and fauna by predation, competition or by altering natural habitat.
The rate of species loss by deforestation is about 1000 times greater than the naturally occurring background extinction rate that existed prior to the existence of human beings (Wilson, 1988.).
However the rate of natural extinction was perhaps one species every thousand year, but man’s intervention has speeded up extinction rates.
Between 1600 and 1950 AD the rate of extinction went up to one species every 10 years while currently, it is perhaps one species every year (Agrawal, 2000 & Hosetti, 2002.).
To talk in terms of number of species, Majupuria (1990) stated that since 1600 AD about 120 species of mammals, 225 species of birds have become extinct and 650 species of birds and mammals are in danger of becoming extinct all over the world.
As far as India is concerned about 88 species of mammals, 55 species of birds, 1 species of amphibian and 23 species of reptiles have been categorised as endangered and listed in Schedule I of Wildlife (protection) Act 1972 amended upto 2002 (Saxena, 2003).
Loss of Earth’s Biological diversity is one of most pressing environmental and development issue. In 1992 the ‘Earth summit’ at Rio (Brazil) laid immense stress on biological diversity of our globe. A convention was signed at this summit which is known as “Convention on Biodiversity”. More than 160 countries have ratified the Convention on Biological Diversity (CBD), and therefore, as per the Article 6 of the CBD are expected to initiate inventory of various components of biodiversity and institute measures for in situ conservation and monitoring, particularly with the participation of local communities (Rawat, 2009).
It is not easy to record, describe or even count exact number of species. Life forms are so diverse that many years of specialized training are required to be able to recognise and describe them. The estimation of biodiversity is perhaps the greatest challenge for it would require millions of man days for painstaking work by highly trained biologists.
The preparation of a list of species is basic to the study of biodiversity, because a list indicates species diversity in a general sense (Bibby et al., 1992 and Bibby, 1998).
Conclusion
To conclude, biodiversity is sum total of all living organisms which are very vital for human existence, whose existence is threatened by various factors, mostly anthropogenic and therefore we must come forward to preserve and conserve it to sustain our own existence.
Bravo,keep it up Rahul
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