Importance of biodiversity

Biodiversity is important for the sustenance and well being of Human race. Biotic resources provide food, fruit, seed, fodder, medicines and a host of other goods and services. Biodiversity also has enormous social and cultural importance. Living organisms provide many ecological services free of cost that are responsible for maintaining ecosystem health.

Thus biodiversity is essential for the maintenance and sustainable utilisation of goods and services from ecological system as well as from individual species.

Protection of water resources: Natural vegetation cover helps in maintaining hydrological cycles, regulating and stabilizing water run-off and acting as a buffer against extreme events such as floods and droughts. Vegetation removal results in siltation of dams and waterways. Wetlands and forests act as water purifying systems, while mangroves trap silt thereby reducing impacts on marine ecosystems.

Soil protection: Biological diversity helps in the conservation of soil and retention of moisture and nutrients. Clearing large areas of vegetation cover has been often seen to accelerate soil erosion, reduce its productivity and often result in flash floods.

Nutrient storage and cycling: Ecosystem performs the vital function of recycling nutrients found in the atmosphere as well as in the soil. Plants are able to take up nutrients, and these nutrients then can form the basis of food chains, to be used by a wide range of life forms. Nutrients in the soil, in turn, is replenished by dead or waste matter which is transformed by micro-organisms; this may then feed others such as earthworms which also mix and aerate the soil and make nutrients more readily available.

Pollution reduction: Ecosystems play an important role in maintenance of gaseous composition of the atmosphere, breakdown of wastes and removal of pollutants. Some ecosystems, especially wetlands have the ability to breaking down and absorb pollutants. Natural and artificial wetlands are being used to filter effluents to remove nutrients, heavy metals, suspended solids; reduce the biological oxygen demand and destroy harmful micro-organisms. Excessive quantities of pollutants, however, can be detrimental to the integrity of ecosystems and their biota.

Climate stability: Vegetation influences climate at macro as well as micro levels. Growing evidence suggests that undisturbed forests help to maintain the rainfall in the vicinity by recycling water vapor at a steady rate back into the atmosphere. Vegetation also exerts moderating influence on micro climate. Cooling effect of vegetation is a common experience which makes living comfortable. Some organisms are dependent on such microclimates for their existence.

Maintenance of ecological processes: Different species of birds and predators help to control insect pests thus reduce the need and cost of artificial control measures. Birds and nectar–loving insects which roost and breed in natural habitats are important pollinating agents of crop and wild plants. Some habitats protect crucial life stages of wildlife populations such as spawning areas in mangroves and wetlands.

Recreation: Forests, wildlife, national parks and sanctuaries, garden and aquaria have high entertainment and recreation value. Ecotourism, photography, painting, film making and literary activities are closely related.

Cultural values: Plants and animals are important part of the cultural life of humans. Human cultures have co-evolved with their environment and biological diversity can be impart a distinct cultural identity to different communities. The natural environment serves the inspirational, aesthetic, spiritual and educational needs of the people, of all cultures. In a majority of Indian villages and towns, plants like Tulsi (Ocimum sanctum), Peepal (Ficus religiosa), Khejri (Prosopis cineraria) are planted and considered sacred and worshipped.

India is uniquely rich in all aspects of biodiversity including ecosystem, species and genetic biodiversity. For any one country in the world, it has perhaps the largest array of environmental situations by virtue of its tropical location, varied physical features and climate types.

India has the widest variety of ecosystems. With only 2.4 per cent of the land area, India accounts for 7-8 per cent of the recorded species of the world. More than 45000 species of plants and 81,000 species of animals are found in India. India is also one of the eight primary centers of origin of cultivated plants and has a rich agricultural biodiversity.

The trans-Himalayan region with its sparse vegetation has the richest wild sheep and goat community in the world. The snow leopard (Panthera uncia) and Black-necked Crane (Grus nigricollis) are found here. The Great Indian Bustard (Ardeotis nigriceps) which is highly endangered bird, is found in (Gujrat) region, rich in extensive grasslands.

North-east India is one of the richest regions of biodiversity in the country. It is especially rich in orchids, bamboos, ferns, citrus, banana, mango and jute. India is also rich in coral reefs. Major reef formations in Indian seas occur in the Gulf of Mannar, Palk Bay, Gulf of Kutch, the Andaman and Nicobar Islands and the Lakshadweep.

CAUSES OF BIODIVERSITY DEPLETION

Loss of species is a serious cause of concern for human survival. It has been observed that 79 species of mammals, 44 of birds, 15 of reptiles and 3 of amphibians are threatened. Nearly 1500 species of plants are endangered in India. The threat to survival or loss may be caused in the following three ways:

• Direct ways: Deforestation, hunting, poaching, commercial exploitation.
• Indirect ways: Loss or modification of the natural habitats, introduction of exotic species, pollution, etc.
• Natural causes - Climate change.

Among these causes, habitat destruction and over-exploitation is the main.

Habitat (natural home) destruction may result from clearing and burning forests, draining and filling of wetlands, converting natural areas for agricultural to industrial areas, human settlements, mines, building of roads and other developmental projects. All these disturb the natural habitats of organisms which either kill the species or cause disturbance of interactions among species.

Fragmentation of large forest tracts (eg. the corridores) affects the species occupying the deeper part of the forest and are first to disappear. Apart from the direct loss of species during the development activities, the new environment is unsuitable for the species to survive. Over exploitation reduces the size of the population of a species and may push it towards extinction.

Introduction of exotic species: Seeds catch on people’s clothes. Mice, rats and birds hitch-hike on ships. When such species land in new places, they breed extra fast due to absence of any enemy and often wipe out the native species already present there. Exotic species may wipe out the native ones. A few examples are-

(i) Parthenium hysterophorus (Congress grass- a tropical American weed) has invaded-- many of the vacant areas in cities, towns and villages in India leading to removal of the local plants and the dependent animals.

(ii) Nile perch, an exotic predatory fish introduced into Lake Victoria (South Africa) threatened the entire ecosystem of the lake by eliminating several native species of the small Cichlid fish that were endemic to this freshwater aquatic system.

(iii) Water hyacinth clogs lakes and riversides and threatens the survival of many aquatic species. This is common in Indian plains.

(iv) Lantana camara (an American weed) has invaded many forest lands in various parts of India and wiped out the native grass species.

Pollution: Air pollution, acid rain destroys forests. Water pollution kills fishes and other aquatic plants and animals. Toxic and hazardous substances drained into waterways kill aquatic life. Oil spills kill coastal birds, plants and other marine animals. Plastic trash entangles wildlife. It is easy to see how pollution is a big threat to biodiversit

The World Conservation Union (IUCN) (formerly known as International Union for the Conservation of Nature and Natural Resources, IUCN) has recognised eight Red List categories according to the conservation status of species.

The IUCN Threat Categories

Extinct: A taxon is extinct when there is no reasonable doubt that the last individual has died.

Extinct in the wild: A taxon is extinct in the wild when exhaustive surveys in known and/or expected habitats have failed to record an individual.

Critically Endangered: A taxon is critically endangered when it is facing high risk of extinction in the wild.

Endangered: A taxon is endangered when it is not critically endangered but is facing a very high risk of extinction in the wild in near future.

Vulnerable: A taxon is vulnerable when it is not critically endangered or endangered but is facing high risk of extinction in the wild in the medium term future.

Lower risk: A taxon is lower risk when it has been evaluated and does not satisfy the criteria for critically endangered, endangered or vulnerable. Data deficient: A taxon is data deficient when there is inadequate information to make any direct or indirect assessment of its risk of extinction.

Not evaluated: A taxon is not evaluated when it has not yet been assessed against the above criteria.

Threatened species:

The IUCN Red list is an authentic source of information for this purpose. The 2000 Red List is the latest available. It uses a set of criteria, relevant to all species and all regions of the world, to evaluate the extinction risk of species. The 2000 Red list contains assessment of more than 18, 000 species; 11,000 of which are threatened (5,485 animals and 5611 plants). Out of these, 1,939 are listed as critically endangered (925 animals, and 1,014 plants).According to the Red List, in India, 44 plant species are critically endangered., 113 endangered and 87 vulnerable. Amongst animals, 18 are critically endangered, 54 endangered and 143 vulnerable.