Need for Conservation of Biodiversity
* Various human activities such as over exploitation, fragmentation of habitats and the introduction of exotic species cause loss of species diversity.
* Currently, more than 15,500 species worldwide are on the verge of extinction.
* The reasons to conserve biodiversity are grouped into three categories: narrowly utilitarian, broadly utilitarian and ethical.
Patterns of Biodiversity
* Latitudinal gradient pattern is the most widely recognised pattern biodiversity in which there is an increase in the species richness from the poles towards the tropics.
* The tropical Amazonian rainforest in South America has the greatest biodiversity with at least two million insect species waiting to be discovered.
* According to Alexander Von Humboldt, within a region, species richness increases with the increasing explored area, but only up to a limit.
Introduction to Biodiversity
* Biodiversity refers to the sum total of diversity that exists at all levels of biological organisation.
* Biodiversity is mainly studied at three levels: genetic diversity, species diversity and ecosystem or ecological diversity.
* Genetic diversity refers to the genetic variations in a single species as well as between distinct species.
* Species diversity refers to the variety of species in a particular geographical area.
* Ecological diversity refers to the difference between ecosystem types and the diversity of habitats within each ecosystem.
* According to the IUCN, 2004, the total number of plant and animal species descried so far is a little more than 1.5 million.
* On earth, more than 70 per cent of all species recorded are animals while plants make up no more than 22 per cent.
* The distribution of species diversity on earth is uneven- the tropical regions are rich in species diversity while the polar regions have fewer species.
* India has about 45,000 species of plants and more than double the number of animal species and it also forms one of the 12 mega diversity countries of the world.
Biodiversity Conservation
* Biodiversity conservation can be done in two ways- In situ or on-site and Ex situ or off-site.
* In In situ conservation, endangered species are protected in their natural habitat so that the entire ecosystem is protected.
* Ex situ conservation methods include protective maintenance of threatened species in zoological parks, botanical gardens and seed and gene banks.
* There are 34 biodiversity hotspots in the world, of which three are in India.
* India has 14 biosphere reserves, 90 national parks and 448 wildlife sanctuaries.
Importance and Loss of Biodiversity
* Communities with more species tend to be more stable than those with fewer species.
* The importance of species diversity was explained by Paul Ehlrich with the help of an analogy- the ‘river popper hypothesis.’
* According to the IUCN Red List 2004, about 784 species have become extinct in the last 500 years, of which 27 species have been lost in the last two decades.
* Ever since life originated on earth, there have been five episodes of mass extinction of species and we are currently witnessing the Sixth Episode of Extinction.
* Currently, there are more than 15, 500 species worldwide that are on the verge of extinction.
* The four major causes of loss of biodiversity are: habitat loss and fragmentation, over-exploitation, alien species invasion and co-extinction.