1) Human population growth, industrialization and changes in the land use patterns: Around 1.8 million species of plants and animals are known to science. The actual number of species have been existing is >10—1.8millions. Though new species have been continually identified, the rate of extinction is very high (10-20,000 species per year i.e., 1000 to 10,000 times faster rate). Human actions are expected to exterminate 25% of worlds species in next 20-30 years. The mega extinction spasm is related to human population growth, industrialization and changes in the land use patterns in India. The reasons are:
i Forests and grasslands are changed to agricultural land. Encroachments are being repeatedly legalized.
ii Natural wetlands are drained to establish crop lands leading to loss of aquatic species.
iii Mangroves have been cleared for fuel wood and prawn farming, which has led to decrease in the habitat essential for breeding of marine fish.
iv Grasslands are changed to other forms, degraded by overgrazing. Loss to cattle, goat and sheep.
v Natural forests are being deforested for timber and replanted for teak, sal etc. Such monoculture does not support biodiversity as in forests which has closed canopy and rich undergrowth. Excess collection of fire wood by lopping of branches of trees canopy is opened up altering the local biodiversity.
vi Foraging cattle retard regeneration of forest as young seedlings are trampled. vii Ever increasing population gradually decrease buffer zones and forested areas. A prime example is Gir national park, the last bastion of Asiatic lion with a meter gauge railway line, state expressway and 3 temples.
viii Repeated fires by local grazers to increase growth of grass ultimately reduce regeneration of grasses. ix Introductions of exotic weeds eg. lantana bushes, Eupatorium shrubs and congress grass are invading at the expense of indigenous undergrowth species. Following traditional farming techniques like slash and burn in Himalayas, and rab, lopping of tree branches for making wood ash fertilizer in Western ghats are now leading to loss of biodiversity.
x Over harvesting of fish by large trawling boats is leading to depletion of fish stocks. Marine turtles caught in the net are massacred of the coast of Orissa. The rare whale shark, a highly endangered species, is being killed off the coast of Gujarat. 2) Poaching: Specific threats to certain animals are related to large economic benefits. The skin and bones from tigers, ivory from elephants, horns from rhinos and perfume from the musk deer are extensively used abroad. Bears are killed for their gall bladders. Corals and shells are also collected for export or sold on the beaches of Chennai, Kanyakumari and the Andaman and Nicobar islands. Tortoises, exotic birds and other small animals are packed into tiny containers and smuggled abroad for the pet trade. A variety of wild plants with real or sometimes, dubious medicinal values are being overharvested. The commonly collected plants include Rauwolfia, Nux vomica, Datura, etc. The garden plants collected for illegal trade include orchids, ferns and mosses.
3) Man wild life conflicts: Conflicting situations with wild life starts causing immense damage and danger to man. Ex: In Sambalpur, Orissa 195 humans are killed in last 5 years by elephants and in retaliation villagers killed 98 elephants and badly injured more than 30 elephants. Similarly incidents with tigers, leopards etc. are in news.Shrinking forest cover, human encroachment, ill and weak animals, lack of food (one adult elephant needs 200 kg green fodder and 150 kg of clean water) for animals, protecting villagers by putting electric fence are the main reasons for such happenings. As the compensation by government. is not enough, conflicts occur between forest department and villagers. Endangered & endemic species in India
Several species of plants and animals have been endangered due to human activities. The Species whose existence is in danger by human activities are called Man-wild life harmony
Man- wild life conflicts endangered species. These endangered species have been categorized into four viz, 1) Vulnerable 2) Rare 3) Intermediate 4) Threatened. Endangered species which are on verge of extinction are called threatened species. Most of the endangered species are found today only in protected areas (PAs). Some eg of the species being Tiger, rhino, elephant; bird species include Siberian crane, great Indian bustard, Florican, vultures; reptiles and amphibians. Habitat loss caused by human activity is causing threat to plants species like orchids. Over harvesting as ingredients in medical products or cosmotics is also threatening species. To protect endangered species India has created a wildlife protection act. Under this plants and animals are characterized according to thereat to their survival.
The species which are unique to a locality/region are called endemic species. Some species are found only in India and are thus endemic (restricted to our country). Some have very localized distribution and are considered highly endemic. Some species of this category being Indian wild ass, angular kashmiri stag, golden langur, pigmyhog. Conservation of biodiversity: is of two types i.e., In situ and Ex situ In situ conservation: Conserving a species in its own environment by creating national parks and wildlife sanctuaries.
Habit is protected with all the other spp that in it in nature Biodiversity at all levels can be best preserved in situ by setting aside wildness as protected areas (in national parks and wildlife sanctuaries) with distinctive ecosystem included in the network. Such net work preserve the total diversity of life of the region. Biologists view point is to deal with areas which are 1) Species rich 2) Rare /threatened/endangered species / endemic species are found should be given imp as there spp would easily become extinct due to human activity. For eg. Elephants utilize open grasslands after the rains (when it is nutritious) but move into forest to feed on foliage in dry season. Hence a PA for elephant must be large to include a diverse habitat that supports a complete complement of interlinked species.
India has 589 PAs of which 89 are national parks and 500 are wildlife sanctuaries. Over 100 PAs are created in Andaman and Nicobar to preserve the special island ecosystem. The great Himalayan national park is the largest sanctuaries in the ecosystem and is the home of snow leopard. Dachigam sanctuary for hangul or kashmiri stag; Kaziranga national park for animals like elephant, guar, wild boar and swamp deer, and birds like ducks geese, pelicans and storks; Manas sanctuary forGolden langur, pigmy hog and wild boar are some of the examples worth mentioning under in situ conservation. Ex situ conservation: Conserving the species outside the natural habitat in a carefully controlled situation, such as botanical garden for plants or zoological parks for animals, expertise exists to multiply species under artificially managed condition. Gemplasm is preserved in a gene bank for future need, this is taken up for expensive endangered /extinct species. Care is taken to avoid inbreeding such that weak offspring would not develop. Breeding programmes in zoos provide animal needs including enclosures that simulate their wild habitat. Modern zoos function is to breed endangered species as a conservation. Successful examples are
1. Madras crocodile trust bank has successfully bred the 3 crocodiles. Here crocodiles lay two clutches of eggs in one year year instead of one in wild . 2. Guchali zoo has bred pigmy hog
3. Delhi zoo has bred the rare Manipur brow antlered deer.
The successful breeding programme also to aims at reintroduction of the species into wild habitat, with simultaneous removal of problems like poaching disturbances and man made influences.
Conservation of cultivars and livestock breeds:
Fifty years ago nearly 30,000 rice var. were grown in India now only a few of these are cultivated. The new varieties being developed use the germplasm of these original types. But if all these traditional types vanish, it would be difficult to develop new disease resistant varieties for future. Use of varieties from gene banks have been expensive and risky. Farmers need to be encouraged to grow traditional varieties. This is a concern for future of mankind. Gene banks have at present 34,000 creeds and 2200 pulses). Traditional breeds/ varieties have to be encouraged for genetic variability. In contrast men interested in cash returns in short time wouldnt appreciate the benefits of growing indigenous varieties.
Biological Diversity act 2002:
Biological diversity is a national asset of a country, hence the conservation of biodiversity assumes greater significance. The first attempt to bring the biodiversity into the legal frame work was made by way of the biodiversity bill 2000 which was passed by the Lok sabha on 2nd December 2002 and by Rajya Sabha on the December 2002. Objectives of the act:
1. To conserve the Biological Diversity
2. Sustainable use of the components of biodiversity
3. Fair and equitable sharing of benefits arising out of the use of the B.D A national biodiversity authority has been established by the Biodiversity Act 2002 to regulate act implementing rules 2004 has been operationalised since coming in to force. Act: Regulating access well as pushing the officially sponsored documentation of biological resources and traditional practices through peoples diversity registers at the local and data bases at the national levels, respectively. It further probes the extent to which the principles of conservation have realized.