Biodiversity is the part of nature which includes the difference in genes among the individuals of a species, the variety and richness of all the plant and animal species at different scales in space, locally in a region, in the country and the world and various types of ecosystems, both terrestrial and aquatic within a defined area. Biodiversity deals with the degree of natureâ€™s variety in the biosphere.
Types of biodiversity
Genetic diversity -Â the genetic variability within a species.
Species diversity -Â the variety of species within a community
Ecosystem diversity -Â the organisation of species in an area into distinctive plant and animal communities.
Some areas are more rich in species than others. Natural undisturbed tropical forests have a much greater species richness than plantations. A natural forest ecosystem provides a large number of non-wood products that local people depend on such as fruit, fuel wood, fodder, fiber, gum, resin and medicines. Timber plantations do not provide the large variety of goods that are essential for local consumption. In the long-term the economic sustainable returns from non-wood forest products is said to be greater than the returns from felling a forest for its timber. Thus the value of a natural forest, with all its species richness is much greater than a plantation. At present conservation scientists have been able to identify and categorise about 1.75 million species on earth. However, many new species are being identified, especially in the flowering plants and insects. Areas that are rich in species diversity are called â€˜hotspotsâ€™ of diversity. India is among the worldâ€™s 15 nations that are exceptionally rich in species diversity.
There are a large variety of different ecosystems on earth, which have their own complement of distinctive inter linked species based on the differences in the habitat. Ecosystem diversity can be described for a specific geographical region, or a political entity such as a country, a State or a taluka. Distinctive ecosystems include landscapes such as forests, grasslands, deserts, mountains, etc., as well as aquatic ecosystems such as rivers, lakes, and the sea. Each region also has man-modified areas such as farmland or grazing pastures. An ecosystems is referred to as â€˜naturalâ€™ when it is relatively undisturbed by human activities, or â€˜modifiedâ€™ when it is changed to other types of uses, such as farmland or urban areas. Ecosystems are most natural in wilderness areas. If natural ecosystems are overused or misused their productivity eventually decreases and they are then said to be degraded. India is exceptionally rich in ecosystem diversity.
AÂ biodiversity hotspotÂ is aÂ biogeographicÂ region with a significant reservoir ofÂ biodiversityÂ that is under threat from humans. To qualify as a biodiversity hotspot on Myers 2000 edition of the hotspot-map, a region must meet two strict criteria:
1. it must contain at least 0.5% or 1,500 species ofÂ vascular plantsÂ asÂ endemics, and
2. it has to have lost at least 70% of its primary vegetation.
Around the world, at least 25 areas qualify under this definition, with nine others possible candidates. These sites vascular support nearly 60% of the world's plant, bird, mammal, reptile, and amphibian species, with a very high share of endemic species. Three regions that satisfy these criteria exist in India and are described below. For a more detailed information about these hotspots, go to theBiodiversityhotspots.org homepage
The Western Ghats and Sri Lanka
TheÂ Lion tailed macaqueÂ is a flagship species of the Western Ghats