Units of biodiversity may range from the genetic level within a species to the biota in a specific region and may extend up to the large diversity found in different biomes.
- Genetic diversity
It is the basic source of biodiversity. The genes found in organisms can form an enormous number of combinations, each of which shows some variability. Genes are the basic units of hereditary information transmitted from one generation to another. When the genes within the same species show different properties due to new combinations, it is called genetic variability. For example, all rice varieties belong to the species Oryza sativa, but thousands of wild and cultivated varieties of rice show variations at the genetic level and differ in their color, size, shape, aroma, and nutrient content of the grain. This is the genetic diversity of rice.
- Species diversity
It is the variability found within the population of a species or between different species of a community. It represents the species richness and their abundance in a community in a broad spectrum. There are two popular indices of measuring species diversity known as the Shannon-Wiener index and Simpson index. The estimates of actual numbers vary widely due to incomplete and indirect data. The current estimates given by Wilson in 1992 put the total number of living species between 10 million to 50 million. Till now only about 1.5 million living and 300,000 fossil species have been described and given scientific names. A large fraction of these species may become extinct even before they get discovered and enlisted.
- Ecosystem diversity
This is the diversity of ecological complexity showing variations in ecological niches, trophic structure, food-webs, nutrient cycling, etc. The ecosystems also show variations for physical parameters like moisture, temperature, altitude, precipitation, etc. Thus, there occurs tremendous diversity within the ecosystems, along these gradients. We may consider diversity in the forest ecosystem, which is supposed to have mainly a dominance of trees. But, while considering a tropical rainforest, a tropical deciduous forest, a temperate deciduous forest, and a boreal forest, the variations observed are just too many and they are mainly due to variations in the mentioned physical factors. The ecosystem diversity is of great value that must be kept intact. This diversity has risen and developed over millions of years of evolution. If we destroy this diversity, it would disrupt the ecological balance. We cannot even replace the diversity of one ecosystem with that of another. Coniferous trees of boreal forests cannot take up the function of the trees of tropical deciduous forest lands and vice versa, because ecosystem diversity has evolved to the prevailing environmental conditions with a well-regulated ecological balance.
The climate and topography changes in different parts of the country and these variations have induced enormous variability in flora and fauna. India has a rich heritage of biological diversity and occupies the tenth position among the plant-rich nations of the world. We must study the distribution, evolution, dispersal, and environmental relationship of plants and animals in time and space. Biogeography which includes phytogeography and zoogeography deals with these aspects of plants and animals. To gain insight into the distribution and environmental interactions of flora and fauna of our country, it has been classified into ten biogeographic zones. Each of these zones has its characteristic climate, soil, topography, and biodiversity.
The value of biodiversity in terms of its commercial utility, ecological services, social and aesthetic value is enormous. We get benefits from other organisms in so many ways. Many times, we realize and appreciate the value of the organism only after it is lost from this earth. A very small, insignificant, useless looking organism may play a crucial role in the ecological balance of the ecosystem or maybe a potential source of some invaluable drug for dreaded diseases like cancer or AIDS. The multiple uses of biodiversity or biodiversity value have been classified by McNeely et al in 1990 as follows:
1 Consumptive use value:
These are direct use values where the biodiversity product can be harvested and consumed directly ex. fuel, food, drugs, fiber, etc.
Food: A large number of wild plants are consumed by human beings as food. About 80,000 plant species from the wild have been reported as edible. About 90% of food crops have been domesticated from wild tropical plants. Even today, our agricultural scientists use the existing wild species of plants that are closely related to our crop plants to develop new hardy strains. Wild relatives usually possess better tolerance and hardiness. A large number of wild animals are also our sources of food.
Drugs and medicines: About 75% of the world’s population relies upon plants or plant extracts for making medicines. The wonder drug Penicillin which is used as an antibiotic is derived from a fungus called Penicillium. Likewise, we get Tetracyclin from a bacterium. Quinine, the cure for malaria is obtained from the bark of the Cinchona tree, while Digitalin is obtained from foxglove (Digitalis) which is an effective cure for heart ailments. Recently, vincristine, two anticancer drugs, have been obtained from the Periwinkle (Catharanthus) plant, which possesses anticancer alkaloids. A large number of marine animals are supposed to possess anti-cancer properties that are yet to be explored systematically.
Fuel: Our forests have been used for ages to fuelwood. The fossil fuels coal, petroleum, and natural gas are also products of fossilized biodiversity. Firewood collected by individuals is not marketed but is directly consumed by tribal and local villagers.
2 Productive use values:
These are the commercially usable values where the products are marketed and sold. It may include lumber or wild gene resources. These can be traded for use by scientists for introducing desirable traits in the crops and domesticated animals. Some examples are the animal products like tusks of elephants, musk from musk deer, silk from silk-worm, wool from sheep, fir of many animals, lac from lac insects, etc, all of which are traded in the market. Many industries depend upon the productive use values of biodiversity e.g.- the paper and pulp industry, Plywood industry, Railway sleeper industry, Silk industry, textile industry, ivory-works, leather industry, pearl industry, etc.
Despite the international ban on trade in products from endangered species, smuggling of fur, hide horns, tusks, live specimens, etc. worth millions of dollars are traded every year. Developing countries in Asia, Africa, and Latin America are the richest biodiversity centers and wildlife products are smuggled and marketed in large quantities to some rich western countries and also to China and Hong Kong where the export of cat skins and snake skins fetches a booming business.
3 Social Value:
These are the values associated with the social life, customs, religion, and psycho-spiritual aspects of the people. In India, many of the plants are considered holy and sacred such as Tulsi (holy basil), Peepal, Mango, Lotus, Bael, etc. The leaves, fruits, or flowers of these plants are used in worship or the plant itself is worshipped. The tribal people are very closely linked with the wildlife in the forests. Their social life, songs, dances, and customs are closely woven around the wildlife. Many animals like Cow, Snake, Bull, Peacock, Owl, etc. also have a significant place in our psycho-spiritual arena and thus hold special social importance. Thus, biodiversity has distinct social value, attached to different societies.
4 Ethical value:
Ethical values are also sometimes known as existence values. It is based on ethical principles like all life must be preserved. It is based on the concept of Live and Let Live. If we want the human race to survive, then we must protect all biodiversity, because biodiversity is valuable. Ethical value means that we may or may not use a species, but knowing the very fact that this species is out there in nature gives us pleasure. We all feel sorry when we learn that passenger pigeon or dodo is no more on this earth. We are not deriving anything directly from Kangaroo, Zebra or Giraffe, but we all strongly feel that these species should exist in nature. This means, there is an ethical value or existence value attached to each species.
5 Aesthetic value:
Great aesthetic value is attached to biodiversity. No one likes to visit vast stretches of barren lands with no signs of visible life. People spend a lot of time and money visiting wilderness areas where they can enjoy the aesthetic value of biodiversity. This type of tourism is now known as eco-tourism. The Willingness to pay concept on such eco-tourism gives us even a monetary estimate for the aesthetic value of biodiversity. Ecotourism is estimated to generate about 12 billion dollars of revenue annually, which roughly gives the aesthetic value of biodiversity.
6 Option values:
These values include the potentials of biodiversity that are presently unknown and need to be explored. There is a possibility that we may find a cure for AIDS or cancer existing within the depths of a marine ecosystem, or a tropical rainforest. Thus, the option value is the value of knowing that biological resources are existing on this biosphere that may one day prove to be an effective option for something important in the future. Thus, the option value of biodiversity suggests that any species may prove to be a gift for us someday. Biodiversity is like the precious gifts of nature presented to us. We should work towards not losing these gifts even before unwrapping them. The option value also includes the option to visit areas where a variety of flora and fauna, or specifically some endemic, rare, or endangered species exist.
7 Ecosystem service value:
Recently, a use-value related to self-maintenance of the ecosystem which is non-consumptive along with various important ecosystem services has been recognized. It refers to the services provided by ecosystems like prevention of soil erosion and floods, maintaining soil fertility, cycling of nutrients, fixation of nitrogen, cycling of water, their role as carbon sinks, pollutant absorption, and reduction of the threat of global warming, etc. Different categories of biodiversity value indicate that ecosystem, species, and genetic diversity all have enormous potential and a decline in biodiversity will lead to huge economic, ecological, and socio-cultural losses.
Extinction or elimination of a species is a natural process of evolution. The earth has experienced mass extinctions in the geologic period. During evolution, species have died out and have been replaced by others. However, the rate of loss of species in the geologic past has been a slow process, keeping in view the vast period going back to 444 million years. The process of extinction has rapidly increased in the recent years of human civilization. In this century, the human impact has been so severe that thousands of species and varieties are becoming extinct annually. One of the estimates by the noted ecologist, E.O. Wilson puts the figure of extinction at 10,000 species per year or 27 per day. This startling figure raises an alarm regarding the serious threat to biodiversity. Over the last 150 years, the rate of extinction has escalated more dramatically. If the present trend continues, we would lose 1/3rd to 2/3rd of our current biodiversity by the middle of the twenty-first century.
Let us consider some of the major causes and issues related to threats to biodiversity.
Destruction and loss of natural habitat are some of the largest causes of biodiversity loss. Billions of hectares of forests and grasslands have been cleared over the past 10,000 years for utilizing them as agricultural lands, pastures, settlement areas, or development projects. These natural forests and grasslands were the natural homes of thousands of species that perished due to the loss of their natural habitat. The wetlands have suffered severe damage thinking them to be useless ecosystems. The unique rich biodiversity of the wetlands, estuaries, and mangroves are under serious threat today. The wetlands are getting destroyed due to draining, filling, and pollution resulting in huge biodiversity loss.
Sometimes the loss of habitat is in instalments so that the habitat is divided into small and scattered patches, a phenomenon is known as habitat fragmentation. There are many wildlife species such as bears and large cats that require large territories to survive. They get badly threatened as they breed only in the interiors of the forests. Due to habitat fragmentation, many songbirds are vanishing.
There has been a rapid disappearance of tropical forests in our country also, at a rate of about 0.6% per year. With the current rate of loss of forest habitat, it is estimated that 20-25% of the global flora would be lost within a few years. The large-scale destruction of the fragile breeding and feeding grounds of our oceanic fish and other species as a result of human intervention poses a serious threat to marine biodiversity.
Poaching
Illegal trading of wildlife products by killing prohibited endangered animals i.e. poaching is another threat to wildlife. Despite the international ban on trade in products from endangered species, the smuggling of wildlife items like furs, hides, horns, tusks, live specimens, and herbal products worth millions of dollars per year continues. The developing nations in Asia, Latin America, and Africa are the richest source of biodiversity and have an enormous wealth of wildlife.
The trading of such wildlife products is highly profiting for the poachers who just hunt down this prohibited wildlife and smuggle it to other countries mediated through a mafia. Elephant tusks are sold for as high as $ 100 per kg; the leopard fur coat is sold at $ 100,000 in Japan while bird catchers can fetch up to $ 10,000 for a rare hyacinth macaw, a beautiful coloured bird, from Brazil. The worse part of the story is that for every live animal that gets into the market, about 50 additional animals are caught and killed.
If you care about rare plants, fish, or birds, please make sure that you are not going for the endangered species or the wild-caught species. Doing so will help in the further decline of these species. Also, do not purchase a fur coat, purse or bag, or items made of crocodile skin or python skin. You will certainly help in preserving biodiversity by doing so.
Man-wildlife conflicts
We have discussed the need to preserve and protect our wildlife. However, sometimes we come across situations of conflict when wildlife starts causing immense harm and danger to man, and in such situations, it becomes very difficult for the forest department to pacify the affected villagers and gain local support for wildlife conservation.
Instances of man-animal conflicts keep on coming to the limelight from several states in our country. In Sambalpur, Orissa 195 humans were killed in the last 5 years by elephants. In retaliation, the villagers killed 98 elephants and badly injured 30 elephants. Several instances of killing elephants in the border regions of the Kote-Chamarajanagar belt in Mysore have been reported recently. The man-elephant conflict in this region has arisen because of the massive damage done by the elephants to the farmer’s ‘cotton and sugarcane crops. The agonized villagers electrocute the elephants and sometimes hide explosives in the sugarcane fields, which explode as the elephants intrude into their fields. More killings are done by locals than by poachers. Recently, in early 2004, a man-eating tiger was reported to kill 16 Nepalese people and a four-year-old inside the Royal Chitwan National Park, 240 km South-west of Kathmandu. The Park renowned for its wildlife conservation effort has become a zone of terror for the locals. At times, such situations were also reported from the border regions of Corbett, Dudhwa, Palamau, and Ranthambore National Parks in our country as well. Very recently in June 2004, two men were killed by leopards in Powai, Mumbai. A total of 14 persons were killed during 19 attacks since January by the leopards from the Sanjay Gandhi National Park, Mumbai which has created a panic among the residents.
Causes of Man-animal conflicts:
The root causes of these conflicts are
(i) Dwindling habitats of tigers, elephants, rhinos, and bears due to shrinking forest cover compels them to move outside the forest and attack the field or sometimes even humans. Human encroachment into the forest areas can cause a conflict between man and the wildlife as it becomes an issue of survival of both.
(ii) Usually the ill, weak, and injured animals tend to attack man. Also, the female tigress attacks the human if she feels that her new-born cubs are in danger. But the biggest problem is that if the tiger tastes human-flesh once then it does not eat any other animal. At the same time, it is very difficult to trace and cull the man-eating tiger and during this process, many innocent tigers are also killed.
(iii) Earlier, forest departments used to cultivate paddy, sugarcane, etc. within the sanctuaries when the favorite staple food of elephants i.e. bamboo leaves were not available. Now due to a lack of such practices, the animals move out of the forest in search of food. It may be noted that one adult elephant needs 2 quintals of green fodder and 150 kg of clean water daily and if it is not available, the animal strays out.
(iv) Many times, the villagers put electric wiring around their ripe crop fields for protection. The elephants get injured, suffer in pain, and turn violent.
(v) Earlier, wild-life corridors were there through which the wild animals used to migrate seasonally in groups to other areas. Due to the development of human settlements in these corridors, the path of wildlife has been disrupted and the animals attack the settlements.
(vi) The cash compensation paid by the government in place of the damage caused to the farmer's’crop is not enough. In Mysore, a farmer gets a compensation of Rs. 400/- per quintal of expected yield while the market price is Rs. 2400/- per quintal. The agonized farmer, therefore, gets revengeful and kills the wild animals.
Remedial Measures to Curb the Conflict
(i) Tiger Conservation Project (TCP) has made provisions for making available vehicles, tranquilizer guns, binoculars, and radio sets, etc. to tactfully deal with any imminent danger.
(ii) Crop compensation and cattle compensation schemes of the adequate amount must be started, along with substantial cash compensation for loss of human life.
(iii) Solar powered fencing should be provided along with electric current proof trenches to prevent the animals from straying into fields.
(iv) Cropping pattern should be changed near the forest borders and adequate fodder, fruit and water should be made available for the elephants within forest zones.
(v) Wildlife corridors should be provided for mass migration of big animals during unfavorable periods. About 300 km2 area is required for elephant corridors for their seasonal migration.
(vi) In the Similipal Sanctuary of Orissa, there is a ritual where wild animals are hunted during the months of April-May for which forest is burnt to flush out the animals. Due to massive hunting by people, there is a decline in the prey of tigers and they start coming out of the forest in search of prey. Now there is a WWF-TCP initiative to curb this ritual of Akhand Shikar in Orissa.
In India, nearly 450 plant species have been identified in the categories of endangered, threatened, or rare. The existence of about 150 mammals and 150 species of birds is estimated to be threatened while an unknown number of species of insects are endangered. A few species of endangered reptiles, birds, mammals, and plants are given below:
(a) Reptiles: Gharial, green sea turtle, tortoise, python.
(b) Birds: Great Indian bustard, Peacock, Pelican, Great Indian Hornbill, Siberian White Crane
(cIarnivorous mammals: Indian wolf, red fox, Sloth bear, red panda, tiger, leopard, striped hyena, Indian lion, golden cat, desert cat, dugong.
(d) Primates: Hoolock gibbon, lion-tailed macaque, Nilgiri langur, Capped monkey, golden monkey.
(eIlants: A large number of species of orchids, Rhododendrons, medicinal plants like Rauvolfia serpentina, the sandalwood tree Santalum, Cycas beddonei, etc.
The Zoological Survey of India reported that Cheetah, Pink-headed duck, and mountain quail have already become extinct from India.
- A species is said to be extinct when it is not seen in the wild for 50 years at a stretch e.g. Dodo, the passenger pigeon.
- A species is said to be endangered when its number has been reduced to a critical level or whose habitats, have been drastically reduced and if such a species is not protected and conserved, it is in immediate danger of extinction.
- A species is said to be in a vulnerable category if its population is facing continuous decline due to overexploitation or habitat destruction. Such a species is still abundant but under a serious threat of becoming endangered if causal factors are not checked.
- Species that are not endangered or vulnerable at present, but are at a risk are categorized as rare species. These taxa are usually localized within restricted areas i.e. they are usually endemic. Sometimes they are thinly scattered over a more extensive area.
India has two biodiversity hot spots and thus possesses a large number of endemic species. Our country is host to almost 47,000 species of plants. Out of these, 7000 are endemic. Thus, the Indian subcontinent has about 62% endemic flora, restricted mainly to the Himalayas, Khasi Hills, and the Western Ghats. Some of the important endemic flora include orchids and species like Sapria himalayana, Uvaria lurida, Nepenthes khasiana, Pedicularis perroter, etc.
A large number out of a total of 81,000 species of animals in our country is endemic. The western ghats are particularly rich in amphibians (frogs, toads, etc.) and reptiles (lizards, crocodiles, etc.). About 62% of amphibians and 50% of lizards are endemic to the Western Ghats. Different species of monitor lizards (Varanus), reticulated python and Indian Salamander, and Viviparous toad Nectophryne are some important endemic species of our country.
The enormous value of biodiversity due to their genetic, commercial, medical, aesthetic, ecological, and optional importance emphasizes the need to conserve biodiversity. Gradually we are coming to realize that wildlife is not just a game to be hunted’, rather it is a ‘gift of nature’ to be nurtured and enjoyed. Several measures are now being taken the world over to conserve biodiversity including plants and wildlife.
There are two approaches to biodiversity conservation:
(a) In situ conservation (within habitat): This is achieved by the protection of wild flora and fauna in nature itself. ex. Biosphere Reserves, Sanctuaries, Reserve Forests, National parks, etc.
(b) Ex situ conservation (outside habitats) This is done by the establishment of gene banks, seed banks, zoos, botanical gardens, culture collections, etc.
In Situ Conservation
At present we have 7 major Biosphere reserves, 80 National Parks, 420 wildlife sanctuaries, and 120 Botanical gardens in our country covering 4% of the geographic area.
The Biosphere Reserves conserve some representative ecosystems as a whole for long-term in situ conservation. In India, we have Nanda Devi (U.P.), Nokrek (Meghalaya), Manas (Assam), Sunderbans (West Bengal), Gulf of Mannar (Tamil Nadu), Nilgiri (Karnataka, Kerala, Tamil Nadu), Great Nicobars, and Similipal (Orrisa) biosphere Reserves. Within the Biosphere reserves, we may have one or more National Parks. For example, Nilgiri Biosphere Reserve has two National Parks viz. Bandipur and Nagarhole National Park.
A National Park is an area dedicated to the conservation of wildlife along with its environment. It is also meant for enjoyment through tourism but without impairing the environment. Grazing of domestic animals, all private rights, and forestry activities are prohibited within a National Park. Each National Park usually aims at conservation specifically of some particular species of wildlife along with others.
Name of National Park | State | Important Wildlife |
Kaziranga | Assam | One-horned Rhino |
Gir National Park | Gujarat | Indian Lion |
Dachigam | J & K | Hangul |
Bandipur | Karnataka | Elephant |
Periyar | Kerala | Elephant, Tiger |
Kanha | M.P. | Tiger |
Corbett | U.P. | Tiger |
Dudwa | U.P. | Tiger |
Ranthambore | Rajasthan | Tiger |
Sariska | Rajasthan | Tiger |
Some important National parks in India
Wildlife sanctuaries are also protected areas where killing, hunting, shooting, or capturing of wildlife is prohibited except under the control of the highest authority. However, private ownership rights and forestry operations are permitted to an extent that they do not affect the wildlife adversely.
Name of Sanctuary | State | Major Wild Life |
Ghana Bird Sanctuary | Rajasthan | 300 species of birds (including migratory) |
Hazaribagh Sanctuary | Bihar | Tiger, Leopard |
Sultanpur Bird Sanctuary | Haryana | Migratory birds |
Nal Sarovar Bird Sanctuary | Gujarat | Waterbirds |
Abohar Wildlife Sanctuary | Punjab | Blackbuck |
Mudumalai Wildlife Sanctuary | Tamil Nadu | Tiger, elephant, Leopard |
Vedanthangal Bird Sanctuary | Tamil Nadu | Waterbirds |
Jaldapara Wild Life Sanctuary | W. Bengal | Rhinoceros, elephant, Tiger |
Wild Ass Sanctuary | Gujarat | Wild ass, wolf, nilgai, chinkara |
Some Important Wildlife Sanctuaries of India
For plants, there is one gene sanctuary for Citrus (Lemon family) and one for the pitcher plant (an insect-eating plant) in Northeast India. For the protection and conservation of certain animals, specific projects have been undertaken in our country e.g. Project Tiger, Gir Lion Project, Crocodile Breeding Project, Project Elephant, Snow Leopard Project, etc.
Ex-situ Conservation:
This type of conservation is mainly done for the conservation of crop varieties, the wild relatives of crops, and all the local varieties with the main objective of conserving the total genetic variability of the crop species for future crop improvement or afforestation programs. In India, we have the following important gene bank/seed bank facilities:
(i) National Bureau of Plant Genetic Resources (NBPGR) is located in New Delhi. Here agricultural and horticultural crops and their wild relatives are preserved by cryopreservation of seeds, pollen, etc. by using liquid nitrogen at a temperature as low as -196°C. Varieties of rice, pearl millet, Brassica, turnip, radish, tomato, onion, carrot, chili, tobacco, poppy, etc. have successfully been preserved in liquid nitrogen for several years without losing seed viability.
(ii) National Bureau of Animal Genetic Resources (NBAGR) located at Karnal, Haryana preserves the semen of domesticated bovine animals.
(iii) National Facility for Plant Tissue Culture Repository (NFPTCR) for the development of a facility for the conservation of varieties of crop plants/trees by tissue culture. This facility has been created within the NBPGR.
The G-15 countries have also resolved to set up a network of gene banks for the conservation of various varieties of aromatic and medicinal plants for which India is the networking co-ordinator country.
Following the 1992 Earth Summit at Rio de Janeiro, it became evident that there is a growing need to know and scientifically name, the huge number of species that are still unknown on this earth. Roughly 1.5 million species are known to date which is perhaps 15% or maybe just 2% of the actual number. Tropical deforestation alone is reducing biodiversity by half a percent every year. Mapping the biodiversity has, therefore, been rightly recognized as an emergency task to plan its conservation and practical utilization in a judicious manner.
Terrestrial biodiversity of the earth is best described as biomes, which are the largest ecological units present in different geographic areas and are named after the dominant vegetation ex. the tropical rainforests, tallgrass prairies, savannas, desert, tundra, etc. The tropical rainforests are inhabited by teeming millions of species of plants, birds, amphibians, insects as well as mammals. They are the earth’s largest storehouse of biodiversity. Many of these species have developed over time in highly specialized niches and that makes them more vulnerable to extinction when their natural home or niche is destroyed. About 50 to 80% of global biodiversity lies in these rainforests. More than one-fourth of the world’s prescription drugs are extracted from plants growing in tropical forests. Out of the 3000 plants identified by the National Cancer Research Institute as sources of cancer-fighting chemicals, 70% come from tropical rain forests. Very recently, extract from one of the creeping vines in the rainforests at Cameroon has proved effective in the inhibition of replication of the AIDS virus. It is interesting to note that the common Neem tree, so popular in tropical India, known for its medicinal properties has now come into the limelight even in the western temperate countries.
There are an estimated 1,25,000 flowering plant species in tropical forests. However, till now we know only 1-3% of these species. Needless to say, we must try in every way to protect our tropical rainforests. In India, The Silent Valley in Kerala is the only place where tropical rain forests occur. You may recall the case of the Silent Valley Hydroelectric Project, which was abandoned mainly because it had put to risk our only tropical rain forest biodiversity. Temperate forests have much less biodiversity, but there is much better documentation of the species. We have roughly 1,70,000 flowering plants, 30,000 vertebrates, and about 2,50,000 other groups of species all over the world that have been described. There is a stupendous task of describing the remaining species which may range anywhere from 8 million to 100 million.
Taxonomic group | Number |
Bacteria & Cyanobacteria | 5,000 |
Protozoans (Single called animals) | 31,000 |
Algae | 27,000 |
Fungi (Molds, Mushrooms) | 45,000 |
Higher Plants | 2,50,000 |
Sponges | 5,000 |
Jellyfish, Corals, etc. | 10,000 |
Flatworms, roundworms, earthworms | 36,000 |
Snails, Clams, Slugs, etc | 70,000 |
Insects | 7,50,000 |
Mites, Ticks, Croaks, shrimps | 1,20,000 |
Fish and Sharks | 22,000 |
Amphibians | 4,000 |
Reptiles | 5,000 |
Birds | 9,000 |
Mammals | 4,000 |
Total | 1,400,000 |
Living species estimates
(World Resource Institute, 1999)
It is interesting to know that marine diversity is even much higher than terrestrial biodiversity and ironically, they are still less known and described. Estuaries, coastal waters, and oceans are biologically diverse and the diversity is just dazzling. Sea is the cradle of every known animal phylum. Out of the 35 existing phyla of multicellular animals, 34 are marine and 16 of these are exclusively marine.
Every country is characterized by its biodiversity depending mainly on its climate. India has a rich biological diversity of flora and fauna. Overall six percent of the global species are found in India. It is estimated that India ranks 10th among the plant-rich countries of the world, 11th in terms of the number of endemic species of higher vertebrates, and 6th among the centers of diversity and origin of crops. In India, the total number of living species identified is 150,000. Out of a total of 25 biodiversity hot-spots in the world, India possesses two, one of which is in the north-east region and one in the western ghats. India is also one of the 12 mega-biodiversity countries in the world.
Key takeaway
- Biodiversity refers to the variety and variability among all groups of living organisms and the ecosystem complexes in which they occur.
- The various levels of biodiversity are Genetic biodiversity, Species biodiversity, and Ecosystem biodiversity.
- The value of biodiversity in terms of its commercial utility, ecological services, social and aesthetic value is enormous. The biodiversity values have been classified as Consumptive use-value, Productive use-value, Social value, Ethical value, Aesthetic value, Option value, and Ecosystem service value.
- The major causes and issues related to threats to biodiversity are loss of habitat, poaching, and man-wildlife conflict.
- The enormous value of biodiversity due to their genetic, commercial, medical, aesthetic, ecological, and optional importance emphasizes the need to conserve biodiversity. There are two ways to conserve biodiversity: Ex-situ and In-situ.
References:
1. A.K. De, Environmental Chemistry, Wiley Eastern Ltd.
2. E.P. Odum, Fundamentals of Ecology, W.B. Sunders Co., USA.
3. M.N. Rao and A.K. Datta, Waste Water Treatment, Oxford and IBK Publications.
4. Benny Joseph, Environmental Studies, Tata McGraw Hill, 2005.
5. V.K. Sharma, Disaster Management, National Centre for Disaster Management, IIPE,1999.
