Biodiversity

Biodiversity is the natural wealth of Earth. The Convention of Biological Diversity (CBD), 1992 defined biodiversity as the variability among living organisms from all sources including inter alia (among others) terrestrial, marine and other aquatic ecosystems and other ecological complexes of which they are a part of.

The term biodiversity was given by Walter G Rosen in 1985. Biodiversity consists of differences between genetic composition of individuals of a population of animal or plant species or communities and system in which they occur.

Levels of Biodiversity

Genetic Diversity

Represents heritable variations within and between populations of organisms.

Refers to the variations or changes present in the sequences of four base pairs - adenine, thymine, guanine, and cytosine that constitute the DNA.

Provides a mechanism for a population to adapt to their ever-changing environment.

Due to variations, there are better chances that individuals will be genetically adapted to survive in the local environment, eventually producing future generations with these traits.

Can be seen as appearance of difference among individuals of the same species. This happens due to variations at the genetic level.

For e.g., the number of genes is 13,000 in Drosophila, 32,000-50,000 in Oryza sativa and 35,000-45,000 in Homo sapiens.

Species Diversity

Total number of species of living organisms present in a particular region. Functionally, a species can be a strong interactor or a keystone species.

Strong Interactor species are those species whose disappearance would have a significant regression at least on one other species.

Keystone species are those strong interactors whose removal would have a significant effect on the entire ecosystem. They have a dominant influence over the structure of the ecosystem.

Quantitative Assessment of species diversity depends upon the species richness and species evenness.

Species Richness: The total number of different species present in a particular area.

Species Evenness: It is the measure of relative abundance of different species making up the richness of an area.

Ecosystem Diversity

Whittaker (1972) described three terms for measuring biodiversity in ecosystems over geo-graphical scales:

Alpha diversity refers to the diversity within a particular area or ecosystem, and is usually expressed by the number of species (i.e., species richness) in that ecosystem.

Change in species diversity between ecosystems is referred to as beta diversity. We count the total number of species that are unique to each of the ecosystems.

Gamma diversity is a measure of the overall diversity for the different ecosystems within a region or biome.

India - A Megabiodiversity Region

India falls within the region between the Tropic of Cancer and the Equator which receives ample rainfall and remains warm and humid which makes it full of biodiversity. India has four major regions of biodiversity i.e. Himalayas, Gangetic Plains, Southern Peninsula (Deccan Plateau + Western and Eastern Ghats), and Andaman & Nicobar and Lakshadweep island chains.

Among these regions, Himalayas, Andaman & Nicobar Islands and Western Ghats gained a lot of attention worldwide as they have rich bio-heritage. The Western Ghats are also known as the 'endemic crown'. Silent Valley National Park in Palakkad, Kerala has the most number of endemic species. There are 17 countries where biodiversity is at its peak due to favorable climatic conditions.

Biogeographic Zones of India

The scientific study of the geographic distribution of flora and fauna is called biogeography. There are ten bio-geographic zones in India.

Trans-Himalayan Zone

This region includes high altitude, cold desert in Ladakh and Lahaul-Spiti. It is an extension of the Tibetan plateau. Trans-Himalayan zone is a good habitat for wild sheep and goat communities.

Flora: Pine, Deodar, Willow and Poplar.

Fauna: Wild Sheep, Snow Leopard, Black Naked Crane, Tibetan Sheep, Blue Sheep, Alpine Ibex, Tibetan Antelope.

Himalayan Zone

This is one of the richest zones of species diversity on account of presence of diverse habitats. It is the north-east boundary of India. The entire mountain belt runs from Kashmir in the north-west to Assam in the north-east.

Flora: Pine, Oak, Sal, Dhak, Dwarf Bamboo, Junipers.

Fauna: Musk Deer, Brown Bear, Mountain Sheep, Red Panda, Markhor.

Desert Zone

This is comprised of the sand desert of Western Rajasthan and the saline deserts of Gujarat.

Flora: Acacia, Zizyphus, Date Palm, Khejri.

Fauna: Desert Cat, Desert Fox, Blackbuck, Chinkara, Indian Wolf, Lesser Flamingo, Great Indian Bustard

Semi-Arid Zone

It includes 15% of the country's landmass.

Flora: Acacia, Zizyphus, Peepal, B. pendula.

Fauna: Great Indian Bustard, Blackbuck, Chausingha, Chinkara, Spotted Deer, Asiatic Lion, Tiger.

Western Ghats

This includes the mountainous region that runs across the western coast of India. About 30% of plant biodiversity and 60% of animal biodiversity of India can be seen in this region. It accounts about 5.8% of the country's land-mass. It begins from the western extremity of Satpura in South Gujrat and runs along Malabar coast of Kerala.

Flora: Teak, Shisham, Tuna, Bahera.

Fauna: Tiger, Elephant, Gaur, Frogs, Snake, Sloth Bear, Panther.

Deccan Peninsular Zone

This region covers the South and South-Central plateau or river Tapti with mostly deciduous trees. This semi-arid, triangular plateau south of the Narmada valley is the largest biogeographic zone of India and covers 42% of the country's landmass.

Flora: Sal, Teak, Arjun, Palash, Pine, Albizia.

Fauna: Tiger, Sloth Bear, Gaur, Cheetal, Wild Buffalo, Sambar.

North-Eastern Zone

This region comprises non-Himalayan hill ranges of the north-eastern India having a wide variety of vegetation. It includes about 17% of total forest area and about 30% of the total number of plant species are found in this region.

Flora: Bamboo, Sal, Jackfruit, Chestnut, Castor.

Fauna: Rhinoceros, Swap Deer, Hoolock Gibbon, Golden Langur, Pygmy Hog, Hispid Hare and water fowls.

Coastal Zone

The coasts are present in Gujrat, Goa, Kerala, Tamil Nadu, Andhra Pradesh, Odisha and West Bengal. These are distributed across both the western and eastern parts of the country. These areas support a great number of species in mangroves, swamps and coral reefs having high conservation value.

Flora: Coconut, Banana, Cashew.

Fauna: Sea Cow, Marine Turtle, Estuarine Crocodile, Crabs, Lobsters, Oysters, Puffer Fish, Jelly Fish, Mudskippers.

Island Zone

This zone includes Andaman-Nicobar and Lakshadweep group of islands. It has about 372 big and small islands. Among these, only 5 islands are inhabited.

Flora: Palm, Coconut, Cardamom, Cloves, Jackfruit.

Fauna: Crab-eating Macaque Tree Shrew, Sea Cow, Hornbill, Nicobar Pigeon, Hawksbill Turtle, Olive Ridley Turtle.

Biodiversity Hotspots

Hotspots are pockets of nature that contain various species which also includes many rare and endangered species which are found nowhere else on the planet and have been threatened to a significant degree by human actions.

The concept of hotspot was given by Norman Myer. Myer described hotspot as a geographical area which is highly diverse in species, rich in endemic, rare and endangered species but found at small areas and are facing a significant threat of habitat loss. Previously, Myer marked 25 hotspots which are now 36 in number. Out of these 36 hotspots, 4 are in India.

Endangered and Endemic Species of India

Endemic Species of India

Endemic species are those species which are found in a particular area and nowhere else in the world. They may be local endemics, national endemics, or geographical endemics. There may be various reasons for a species to be endemic to a particular area, for example, island isolation, particular life cycles, feeding or breeding ground isolation, habitat preferences, etc. Some examples of endemic species are (a) Asiatic lion found in and around Gir National Park, Gujrat, (b) Lemur found in Madagascar, (c) Pygmy Hog found in Jorhat, Assam, (d) Indian purple frog found in Western Ghats, India, etc. Many endemic species are currently facing a huge risk of extinction, primarily because of habitat loss. Most of the endemic species in India are found in Himalayas, North Eastern region, Western Ghats, and Andaman-Nicobar Islands. Among these regions, Himalayas and Western Ghats are home to 60% of total endemic species found in India.

Endangered Species of India

They are those species which also face risk of extinction but comparatively less than critically endangered species. For example, Royal Bengal Tiger, Asian Elephant, Golden Langur and Blue Whale.

Biological Invasion

The process by which species breach geographical barriers and extend their range is called as biological invasion. The invasive species breach the natural barriers like large rivers, mountains and deserts. They are competitive in their non-habitats as they are subjected to less predator disturbance. These species have high reproduction rate, high dispersal rate, long longevity, high genetic variability, wide range of diet, etc. All exotic species are not invasive species. Invasive species causes harm to human beings, ecology and environment. Some examples of invasive species are as follows:

Nile Perch is an exotic predatory fish introduced into Lake Victoria threatens the entire ecosystem of the lake by eliminating several native species of small Cichlid fish.

Water Hyacinth (Jalkumbhi) clogs the rivers and lakes and threatens the survival of many aquatic species in lakes, rivers and flood plains of India.

Lantana camara (Wild sage) has invaded many forest lands and strongly compete with native species.

Acacia farnesiana (Bilati Babool)

Parthenium hysterophorus (Congress grass)

IUCN Red List Criteria

International Union for Conservation of Nature and Natural Resources Red List system was initiated in 1963 and since then, evaluation of conservation status of species and subspecies is continuing on a global scale. The Red List provides information to international agencies such as Convention on Biological Diversity (CBD) and Convention on International Trade in Endangered Species of wild fauna and flora (CITES).

The Red List is the most comprehensive inventory of the global conservation status of plant and animal species. Some important endangered species in India are as follows:

Flora: Orchids, many medicinal plants, pitcher plant, sandalwood.

Reptiles: Gharial, green turtle, tortoise, python.

Birds: Great Indian Bustard, peacock, pelican, Great Indian Hornbill, Siberian crane.

Mammals: Indian wolf, Red fox, Red panda, tiger, leopard, hyena, desert cat and sea cow.

Values of Biodiversity

Economic Values

Economic values of biodiversity can be studied on terms of consumptive use value and productive use value. Consumptive use of biodiversity refers to the provision of food including cereals, milk, meat, and other crops that help sustain the local population, provision of medicines derived from plants like A. belladona, Thuja, Cinchona, Periwinkle, Isabgol and fungi like Penicillium, and provision of timber, fuelwood and fodder to the local people for direct use. Productive use of biodiversity refers to the possibilities of manufacturing marketable goods like furniture, drugs and pharmaceuticals, improved varieties of crops, rare ornamental species from bio-rich areas.

Ecological Values

Biodiversity is essential for preserving ecological processes, such as, nutrient cycling and fixation, genesis of soil or soil formation, maintaining balance between ecosystems, local flood reduction, waste disposal, air and water purification, solar energy absorption, control of disease-carrying organisms, suppression of pests, maintaining soil fertility and controlling soil erosion.

Social Values

People value biodiversity as a part of their livelihood as well as through cultural and religious sentiments. Indian civilization has over several generations preserved nature through local traditions. This has been an important part of the ancient philosophy of many of our cultures. We have in our country, a large number of sacred groves or deorais preserved by tribal people in several states. Sacred groves around ancient sacred sites and temples act as gene banks of wild plants. A particular species or community of organisms may have emotional value for a group of people who feel that their identity is inextricably linked to the natural components of the environment that shaped their culture.

Ethical Values

Ethical values related to biodiversity conservation are based on the importance of protecting all forms of life. All forms of life have the right to exist on the planet i.e. live and let live. There are several moral and ethical values which are associated with the sanctity of all forms of life. There is also a psychological need for access to wildlife.

Aesthetic Values

It refers to the appreciation of biodiversity for its creativity, beauty, pleasure and excitement when a person visits around such regions. Apart from utilization of wildlife for consumptive use or productive use, biodiversity hotspots can be very good tourist spots. A new concept, i.e., ecotourism, developed due to the aesthetic values of biodiversity. Ecotourism is defined as responsible travel to natural areas that conserve the environment, sustains the wellbeing of the local people and enriches interpretation of and education about biodiversity.

Informational Values

Keeping future possibilities open for their use is called informational value. It is impossible to predict which of our species or traditional varieties of crops and domestic animals will be of great use in the future. To continue to improve cultivars and domestic livestock,we need to return to wild varieties of crop plants and animals. The hunt for various species under the scope of biotechnology, is already underway for finding solutions to various environmental problems. The zebra fish has recently proved to be an especially useful model for understanding the molecular genetics of neural development.

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