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Chapter- 15
Biodiversity and Conservation
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Large and diverse communities of biota occupy distinct climatic zone forming ecosystems
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It is the shortened and combined version of two
words- “biological” and “diversity”
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They include the species of micro-organisms, algae, fungi, plants, animals, occurring on the
earth in various habitats and the ecological complexes and niches of which they are a part
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MAGNITUDE OF BIODIVERSITY
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India has approximately 45,000 species of plants and nearly twice as many species of animals
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Numerous species that are yet to be identified are believed inhabit tropics and coral reefs
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Inventories are nearly complete for most groups of organisms in the temperate areas
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50
million
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Among the animals, insects are the most numerous (about 70%) with present estimate of 7 out of 10 animals
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With that information the
magnitude of biodiversity will further increase
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Genetic diversity
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It is the diversity in the number and type of genes as well as chromosomes present in different species and the
variations in the genes and their alleles in the same species
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Variation in the genes of a species increase with increase in size and environmental parameters of the habitat
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It helps in speciation or evolution of new species
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However it is more susceptible to degradation and prone to mass scale destruction at the hands of fungal or
insect attacks
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Species diversity
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It is the diversity and variety in the number and richness of the species of a region
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Number of individuals of different species in a given area represents species evenness or species equitability
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Communities where one or more species have more individuals than other, show dominance or unevenness
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Odum et al (1960) calculate species diversity as number of species per thousand individuals while Menhinick
(1964) calculates it as number of species in relation to square root of total number of individuals
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α – diversity is dependent upon species richness
and evenness
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Variations are limited
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It is diversity which appears along a gradient of habitat within
geographical area
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(iii) Gamma diversity
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Ecosystem diversity is the variety of forms in the ecosystem due to diversity of niches, trophic levels and
ecological processes like nutrient recycling, food webs, energy flow, role of dominant species and various biotic
interactions
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The country has 10 biogeographical regions
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India has 89 national parks, 492 wild life sanctuaries, 14 biosphere reserves, 6 wetlands and 5 world heritage
sites
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Deccan peninsula is the largest biogeographical region and the Western ghat and north-east are regions richest
in biodiversity
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The richest regions are the Himalayas, Western Ghats
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Biodiversity is more in temperate areas but is maximum in tropical rain
forests
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This has allowed for stability in the environment allowing more species to
develop
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However, very harsh conditions prevail
for most of the year in arctic regions
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1 ha in tropical forests and 21-48 species 0
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Their number would 10/0
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(ii) Altitudinal gradient
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A decrease in species diversity occurs as we ascend high mountains due to drop in temperature and greater
seasonal variability
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• The relationship between species richness and area is a rectangular hyperbola for a wide variety of taxa whether
they are birds, bats, fresh water fishes or flowering plants
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• Here S is species richness, Z is slope of line or regression coefficient, C is y-intercept while A is area
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1-0
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However, when the species area relationship is considered for a very large area like whole continent, retrogression
coefficient or slope of the line comes to have Z value of 0
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2, e
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frugivorous birds and mammals of tropical
forests of different continents with a steeper line of 1
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IMPORTANCE OF BIODIVERSITY
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It can be seen that 85% of the
food output is produced by less than 20 species
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Utilisation of more and more food plants has to be made
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Source of fats and oils
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The major oil seed plants are soybean, coconut, cotton seed, peanut and sunflower, sesame, safflower, mustard
and oil palm
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Bitter colocynth,
jojoba seed
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Fibres
The major sources of fibre are cotton, jute, flax, hemp, sun hemp, rosella, coir and agave
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Rice has been made resistant to four main diseases by crossing it with wild species ( Oryza nivara) from India
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Drugs and medicines
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A number of drugs are based on plant products
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The same are now being synthesized chemically
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25% of all drugs are currently sourced from 120 species of plants
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It is
possible to manufacture innumerable synthetic products from plant chemicals
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Aesthetic value
of biodiversity can be utilized for ecotourism, bird watching, wildlife, pet keeping and gardening
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Cultural benefits
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Historically people have associated themselves with certain specific plants and animals
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Trees of Ficus religiosa (Peepal) and Prosopis cineraria (Khejri) are considered sacred
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Many birds are believed to be sacred
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Every country and state recognizes a particular plant and particular animal as symbol of national and state pride
and cultural heritage
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Ecosystem services
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To maintain and utilize products and services of various ecosystems and individual species biodiversity is
required
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Amazon rain forest are considered lungs of planet earth as they give out 28% of total oxygen
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It is also
important for pollination by insects and birds, nutrient cycling, conservation and purification of water, formation
and protection of soil etc
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THREATS TO BIODIVERSITY
The world is facing accelerated rate of species extinction, largely due to human interference
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It can come through destruction or fragmentation of natural habitat through filling wetlands, ploughing
grasslands, cutting down trees, burning a forest and clearing some area of vegetation
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Migrating animals would go astray and get killed
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Three subspecies of Tiger, dodo, stellar sea cow and passenger pigeon have become extinct in the last 500 years
due to overexploitation by humans
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iii) Alien species invasions:•
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Non-native or alien species are often introduced inadvertently for their economic and other uses
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Island ecosystems are the most vulnerable
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Water hyacinth (Eichhornia crassipes) was introduced with intent to reduce pollution in Indian waters
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This has resulted in death of several
aquatic plants and animals
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It has since then killed and
eliminated ecologically unique diversity of over 200 native species of small Cichlid fish
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Extinction of one will automatically cause extinction of other
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WILDLIFE CONSERVATION
Wildlife conservation is necessary for lot of reasons
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The different living organisms live in equilibrium
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ii) Commercial value of wildlife:
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We have a rich variety of wild life
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This is valuable source of foreign exchange
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iii) Biological studies: Naturalists, zoologists and behavior biologists can study the ecology, physiology and behavior of
the various forms of wildlife in their natural habitats
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iv) Sports and recreation:
The sport of hunting is restricted to a great extent because of the rapidly declining number of animals
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CONSERVATION OF BIODIVERSITY
Conservation of biodiversity is considered under three categoriesA
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Broadly utilitarian
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Food (cereals, pulses, fruits), firewood, fiber, construction material
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Products of medicinal importance
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Broadly utilitarian
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Amazonian forests alone produce nearly 20% of oxygen during photosynthesis
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Aesthetic pleasure we get from the biodiversity
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Each species and variety has an intrinsic value
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Conservation of Biodiversity:
There are two types of conservation strategies – in situ (on site) and ex situ (off site)
IN SITU CONSERVATION
It is conservation and protection of the whole ecosystem and its biodiversity at all levels in order to protect the
threatened species
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Hot spots
These are areas with high density of biodiversity or megadiversity
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Ecological hot spots are determined by four factors
(i) Number of species/ species diversity
(ii) Degree of endemism
(iii) Degree of threat to habitat due to its degradation and fragmentation
(iv) Degree of exploitation:
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Mayers (1988) initially identified 12 hot spots with 14% of plant species in an area of only 0
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Today the number of hotspots identified by ecologists is 34 covering an area less than 2% of land surface with
about 20% of human population living there
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Protected areas
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They are ecological / biogeographical area as where biological diversity along with natural and cultural resources
is protected, maintained and managed through legal or other effective measures
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Protected areas include national parks, sanctuaries and biosphere reserves
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Grazing, forestry
and habitat manipulation are not allowed
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1% of geographical area
Sanctuaries
They are tracts of land with or without lakes where wild animals / fauna can take refuge without being hunted
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allowed
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They are meant for preserving
genetic diversity in representative ecosystems of various natural biomass and unique biological communities
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Creation of biosphere reserve was initiated in 1975 under MAB programme of UNESCO
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In India, 17 biosphere reserve have been set up by now
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The area is undisturbed and legally protected ecosystem
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Limited human activity is allowed like resource use, strategies research and
education
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Transition zone has different parts like forestry, agriculture, and tourism and restoration region
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Importance of biosphere reserves includes:
i) Restoration – Biosphere reserve help in restoration of degraded ecosystems and habitat
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iii) Development – They ensure sustainable economic development by maintaining cultural, social and ecological
sanctity
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v) Education and Research – Each biosphere reserve supports education and research in various ecological aspects of
the ecosystem / biome
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MAB program
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Man and biosphere program is an international biological programme of UNESCO which was started in 1971 but
was introduced in India in 1986
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EX SITU CONSERVATION
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These are means of conservation of any desired species or variety away from their natural habitats
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They are live collections of wild and domesticated species in botanical gardens, zoos etc
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Many of them possess seed banks, tissue culture facilities and other ex-situ technologies
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Together they have about 3000 species of mammals, birds, reptiles and amphibians
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Captive breeding is resorted to in those cases where the number of surviving individuals is so small that there is
no realistic chance of in situ survival
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Offsite collection can also be used to restore depleted populations, reintroduce species in the wild and restore
degraded habitats
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(i) Seed banks: Seeds are of two types- orthodox and recalcitrant
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Seeds are allowed to germinate at intervals from plants and thus fresh seeds are developed for storage
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They can be stored for shorter duration after treatment with fungicides in room having air and normal oxygen
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(iii) Tissue culture: It is carried out through callus formation, embryoids, pollen grain culture and shoot tip culture for
those plants which are either seedless, have recalcitrant seed, variable seed progeny or where clone is to be maintained
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Shoot tip culture can be used to maintain virus free plants
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Banana, Potato
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The cryopreserved material is revived through special technique when required
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Convention on Biodiversity
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“The earth Summit” held in Rio de Janeiro in 1992 called upon all nations to take appropriate measures for
conservation of biodiversity and sustainable utilization of its benefits
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