After reading this article you will learn about: 1. Introduction to Biodiversity 2. India as Mega Diversity Nation 3. Our Common Plants 4. Our Common Animals 5. Endangered Plants and Animals.
Introduction to Biodiversity:
India is one of the world’s most biologically and culturally diverse countries. It is also one of the poorest in terms of per capita income.
The existence of mass poverty on an enormous scale lies upon two important facts: first that the country exports natural products that command high prices in overseas markets, such as basmati rice and Darjeeling tea, as well as products like medicinal and aromatic plants that are major inputs in rapidly expanding industries; and second that India has achieved significant capabilities in industrial chemistry and the life sciences (Table 7.2).
India is one of the world’s ‘mega diversity’ countries. It is ranked ninth in the world in terms of higher plant species richness. At the ecosystem level, India is also well-endowed, with ten distinct biogeographic zones.
It also contains two of the world’s 25 biodiversity hotspots, because of their extraordinarily high levels of species-richness and endemicity, and threatened status.
India is considered to be the centre of origin for the following crop species pigeon pea, egg plant cucumber, possibly cotton and sesame. But for millennia, numerous other crop species have been introduced to India and adapted to localised conditions.
As a consequence of both the diversity of these conditions and of the various ethnic populations living in India, the country has become an important centre of diversity of a great many domesticated species, including various cereals, millets, legumes, vegetables, temperate and tropical fruits, fibre crops, medicinal and aromatic plants.
India’s biodiversity is threatened by the destruction and degradation of ecosystems and by over exploitation of species.
More specifically, the threats are inter alia due to the following:
1. Large-scale development projects such as mining and dam and road construction.
2. Conversion of biodiversity-rich ecosystems, such as tropical forests to farmlands and industrial and residential sites.
3. Poaching of wildlife and over-harvesting of forest products.
While there has been no comprehensive assessment of biodiversity loss, three of four mammal species have been lost since 1950, and so also 15-20 plant species have become extinct. By and large over ten per cent of India’s flowering plant species are threatened with extinction. Of particular seriousness is the loss of agro-biodiversity.
In one district of the state of Andhra Pradesh, Orissa and West Bengal, 95 percent of rice varieties previously cultivated are no longer found. Although the causes are various, this situation is primarily due to the replacement of low-input poly-cultural agricultural systems with higher-input monocultures.
India as Mega Diversity Nation:
India has tremendous biodiversity, genetic as well as of species and ecosystems. It contains over 7 per cent of the world’s biodiversity on 2.5 per cent of the Earth’s surface. This diversity can be attributed to the vast variety of landforms and climates resulting in habitats ranging from tropical to temperate, and from alpine to desert.
The number of plant species in India is estimated to be over 45,523 representing about 11.8 per cent of the world’s flora. These include over 17,500 flowering plants of which 4,950 species are endemic to the country.
It is estimated that 32% of Indian plants are endemic to the country and found nowhere else in the world. Among the plant species the flowering plants have a much higher degree of endemism, a third of these are not found elsewhere in the world.
Among amphibians found in India, 62% are unique to this country. Among lizards, of the 153 species recorded, 50% are endemic. High endemism has also been recorded for various groups of insects, marine worms, centipedes, mayflies and fresh water sponges.
India is also considered as one of the world’s eight centers of origin of cultivated plants. India has 51 species of cereals and millets, 104 species of fruits, 27 species of spices and condiments, 55 species of vegetables and pulses, 24 species of fiber crops, 12 species of soil seeds, and various wild strains of tea, coffee, tobacco and sugarcane.
Several hundred species of wild crop relatives are also distributed all over the country, especially in the western and eastern Himalayas, the Western Ghats and the Malabar Coast, north-eastern India, the Gangetic plain, and in the eastern part of the Deccan Plateau which is a major center for wild rice, Citrus Indica, the most primitive species of citrus plants, is found in the Tura hills in Meghalaya.
It is believed that the cultivated varieties of Citrus in India were perhaps developed from this endangered species.
India’s faunal wealth is equally diverse. The total number of animal species is estimated at 91,307, representing about 7.46 per cent of the world’s fauna. India’s known animal diversity includes about 8,61,696 insects, 21,723 fish, 240 amphibians, 460 reptiles, 1,232 birds and 397 mammals. In also includes about 86,413 invertebrates.
The ancient practice of domesticating animals has resulted in India’s diverse livestock, poultry and other animal breeds. India has 26 breeds of cattle, 40 breeds of sheep, 20 breeds of goats, 8 breeds of camels, 6 breeds of horses, 2 breeds of donkeys and 18 breeds poultry birds. India also contains vast microbial diversity.
Although exact numbers of viruses, microscopic algae and other microscopic organisms are not known. India has at least 850 species of bacteria and virus, also 12,500 of fungi.
1. During the last 200 million years, as part of the process of evolution 100 to 1,000 species became extinct every century. In recent centuries human activities have accelerated the extinction of species. Today the extinction rate is 1,000 to 10,000 times higher than the natural rate before human intervention.
2. More than 700 species of vertebrates, invertebrates and vascular plants have become extinct since AD 1600. Untold numbers probably become extinct without ever being identified or described.
3. Some of the habitats richest in biodiversity, such as tropical rainforests, are being destroyed because of human activities. The destruction of a habitat could lead to extinction of species that lived there and can live nowhere else.
4. During last few decades India has cut down at least 50 per cent of its forests, polluted over 70 per cent of its water bodies, built or cultivated over much of its grasslands, and degraded many coastal areas.
5. At least 10 per cent of India’s recorded wild flora (mainly flowering plants) and possibly a larger percentage of its wild fauna are threatened, although how many are on the verge of extinction, no one known.
Our globally accepted national ‘hot spots’ are in the forests of the North-East Himalaya and the Western Ghats, which are included in the world’s most bio-rich areas. The Andaman and Nicobar Islands are extremely rich in species and many subspecies of different animals and birds have evolved.
Among the endemic species i.e., those species found only in India, a large proportion are concentrated in these areas. The Andaman and Nicobar Islands alone have as many as 2000 species of flowering plants and 120 species of ferns. Out of 135 genera of land mammals in India, 85 (63%) are found in the north-east.
The North Eastern States have 1,500 endemic plant species. A major proportion of amphibian and reptile species, especially snakes, are concentrated in the Western Ghats, which is also a habitat for 1,500 endemic plant species. Coral reefs in Indian waters surround the Andaman and Nicobar Islands, Lakshadweep Islands, the Gulf areas of Gujarat and Tamil Nadu. They are nearly as rich in species as tropical evergreen forests.
Our Common Plants:
India is one of the countries with great diversity of plants. Many of these have been domesticated as crops of various kinds, fruit trees, ornamentals and also medicinal plants. They have different growth forms as trees, shrubs, herbs and climbers.
The common plants around the settlement areas as follows:
In hills, coastal areas, swamps and deserts, plants are quite different. Many plants brought from other countries are planted in forestry practices. They are called “exotic plants”. In wild habitats species diversity is much more than plantation, crop fields and village orchards.
Our Common Animals:
In our country, animal variation is extremely high. Most of the higher vertebrates one can find in forests or similar wild habitats and in Zoo gardens. India is one of the country rich in mammals, birds, reptiles, butterflies and diverse marine life forms.
Among the mammals Sambar, Chital, Swamp deer, Barking deer, Black buck, Chinkara, Rhinoceros, Leopard, Asiatic Elephant, Jackal, Fox, Wolf, Royal Bengal tiger, bonnet macque, rhesus macaque, langur are most common forms.
Identically the common birds were hornbills, parakeets, barbets, bulbuls, flycatchers, flamingo and pelicans. Common reptiles were represented by Monitor lizard, Water monitor, Russell’s viper, Tortoise, Charials and house lizards. Bull frog, tree frog and toads were quite common amphibians. India have wide varieties of grasshopper, battles, ants, bees and butterflies.
The marine fauna of India is also fairly very high in number. They represents almost all categories of animals. Crabs, shrimps, fishes, whale, sharks and dolphins are also very common faunal forms of marine habitats.
Endangered Plants and Animals:
Due to rapid habitat loss, and over exploitation in particular large number of epiphytes, herbs, climbers disappear from their native regions over the years. Many orchids, tree, ferns, medicinal herbs of hills, cycads were considered as major endangered plant species.
Identically large number of mammals, birds, reptiles, corals and fishes were demarked as threatened in our country. A good number of conservation sites were declared for protection of such endangered plants and animals.
It includes countrywide 28 tiger project sites, several crocodile conservation programme, Elephant conservation sites and various bird conservation sites. International Union for Conservation of Nature (IUCN) categorized different threatened species of the World for better recognition and subsequent action plan for their conservation (Table 7.3).
As on today, a good number of plant and animal species considered to be extinct from the planet earth due to various natural and anthropogenic activities. The approximate numbers of extinct species of major categories are given in Table 7.4.
Over the years of exploration made by Botanical Survey of India and Zoological Survey of India indicate the fact that many Indian species of plants and animals are said to be threatened in their habitats. An estimated number is shown in the Table 7.5.
On the basis of survey carried out by Botanical Survey of India and also by Zoological Survey of India, the Red data book with respect to endangered plants and animals were already published. Some endangered plants and animals species in India are shown in Table 7.6 and 7.7.