PATTERN OF BIODIVERSITY
Biodiversity varies with the change of altitude and latitude.
Thus the diversity of animals and plants is not uniform throughout the world and shows uneven patterns.
There 2 specific patterns of biodiversity
1. Latitudinal pattern The species diversity is the maximum at equator and decrease as move towards poles.
2. Altitudinal Gradient The impact of altitude is significant on type of biodiversity. Mostly the increasing altitude leads to decrease in only biodiversity as only some species can adapt the conditions prevailing at high altitude.
Following graph gives the clear idea this relationship
3. Species -Area relationship
The German naturalist and geographer, Alexander Von Humboldt, while exploring SouthAmerican jungles, observed that species - richness increased with increasing explored area, but only up to a limit.
This relationship between species richness and explored area is a rectangular hyperbola described by the equation - S = C Az
Where
S is species richness
C is Y-intercept A is area and z is the slope to the line ( regression coefficient). .
On logarithmic scale, the relationship is a straight line, described by the equation - Log S=Log C+Z log A
Ecologist have discovered that value of ‘Z’ always lies in the range of 0.1 to 0.2, irrespective of the taxonomic group (angiosperms, fish or bird), or the region /geographical area.
But if we consider a large area (i.e., whole continent) , the Z-value in the range of 0.6 to 1.2)
RELATIONSHIP BETWEEN SPECIES DIVERSITY AND ECOSYSTEM
Most of the ecologists believe that
Loss of BiodiversityThere is continuous loss of the earth' treasure of species. For example, the colonization of tropical pacific Islands by human has led to extinction of more than 2000 species of native birds.
The Red list of lUCN documented the extinction of 784 species in last 500 years. The last 20 years witnessed the disappearance of 27 species.
Some important examples of recent extinctions are
Dodu (Mauritius), Quagga (Africa), Thylacine (Australia). Steller Sea-cow (Russia), and subspecies of Tiger, like bali, javan and caspian.
The ecologists now warn that-in next l00 years about 50% of all the species on earth will be wiped out. The loss in biodiversity of a region leads to
1. Lowered resistance to environmental changes
2. Decline in the plant production
3, Increased variability in certain ecosystem, pest disease cycles and water use etc.
Causes of loss of Biodiversity
The accelerated rate of species-extinction is largely due to human activities. There are 4-major causes, called ‘The Evil Quartet’, for the loss of biodiversity -
l. Habitat loss and fragmentation
2. Overexploitation
3. Invasion of Alien or exotic species
4. Co-extinctions
The tropical rain forest is the example of the habitat loss where forest covering has been reduced from 14% of land surface to 6%.
The Amazon rain forest, called ‘The Lungs of the Planet ', which harbors millions of species, is being cleared for cultivating soybean or developing grasslands for raising cattle. The pollution is also the factor for degradation of habitat.
When large habitats are broken into small fragments due to various human activities, the population of migratory animals, mammals and birds, that require a large territory, are adversely affected.
For example –
Process of extinction of biodiversity
1. Natural extinction -
With the change of environmental conditions some species have disappeared and the more adaptive species have appeared. This extinction is slow and is called ‘Background extinction’.
2. Mass extinction –
lt is extinction of large number of species due to natural calamities/catastrophes. The extinction of Dinosaurs is one such example.
3. Anthropogenic extinction -
It is the disappearance of species due to human activities. This man-made extinction represents a severe depletion of biodiversity in terms of time. The current rate of extinction is thousand times higher than the background extinction.
If the current rate of losses continues the earth may lose up to 50% of the species by the end of 2 l “Century.
Susceptilibility to extinction -
The species with the following features are more susceptible (vulnerable) to extinction than the other species.
l. Larger body size (eg. Elephant, Bengal Tiger and Lion etc.)
2. Smaller population with low reproductive rate (eg. Blue whale and Giant panda)
3. Fixed habitat or migratory routes (eg. Whooping cranes and Blue whales).
4. Feeding at higher trophic level in the food chain, (eg. Bengal tiger and Bald Eagle).
5. Narrow range of distribution (eg. Island species and woodland caribou).
Conservation of Biodiversity:
Biodiversity is being depleted by the loss of habitat, fragmentation of habitat, over exploitation of resources, human sponsored ecosystems, climatic changes, pollution invasive exotic spices, diseases, shifting cultivation, poaching of wild life etc.
Since the human beings are enjoying all the benefits from biodiversity, they should take proper care for the preservation of biodiversity in all its form and good health for the future generation i.e., the human being should prevent the degradation and destruction of the habitats thereby maintaining the biodiversity at its optimum level.
Conservation of biodiversity is protection, upliftment and scientific management of biodiversity so as to maintain it at its threshold level and derive sustainable benefits for the present and future generation. In other words, conservation of bio-diversity is the proper management of the biosphere by human beings in such a way that it gives maximum benefits for the present generation and also develops its potential so as to meet the needs of the future generations.
Mainly the conservation of biodiversity has three basic objectives:
(a) To maintain essential ecological processes and life supporting systems.
(b) To preserve the diversity of species.
(c) To make sustainable utilisation of species and ecosystems.
Strategies for Conservation of Biodiversity:The following strategies should be undertaken in order to conserve biodiversity:
(1) All the possible varieties (old or new) of food, forage and timber plants, live stock, agriculture animals and microbes should be conserved.
(2) All the economically important organisms in protected areas should be identified and conserved.
(3) Critical habitats for each species should be identified and safeguarded.
(4) Priority should be given to preserve unique ecosystems.
(5) There should be sustainable utilisation of resources.
(6) International trade in wild life should be highly regulated.
(7) The poaching and hunting of wildlife should be prevented as far as practicable.
(8) Care should be taken for the development of reserves and protected areas.
(9) Efforts should be made to reduce the level of pollutants in the environment.
(10) Public awareness should be created regarding biodiversity and its importance for the living organisms.
(11) Priority should be given in wildlife conservation programme to endangered species over vulnerable species and to vulnerable species over rare species.
(12) The habitats of migratory birds should be protected by bilateral and multilateral agreement.
(13) The over exploitation of useful products of wild life should be prevented.
(14) The useful animals, plants and their wild relatives should be protected both in their natural habitat (in-situ) and in zoological botanical gardens (ex-situ)
(15) Efforts should be made for setting up of National parks and wild life sanctuaries to safeguard the genetic diversity and their continuing evolution.
(16) Environmental laws should be strictly followed.
- The species diversity Is maximum in plants (low altitude) and equator (low latitude).
Thus the diversity of animals and plants is not uniform throughout the world and shows uneven patterns.
There 2 specific patterns of biodiversity
1. Latitudinal pattern The species diversity is the maximum at equator and decrease as move towards poles.
- The tropical diversity is highest between latitudinal ranges of 23.5°N to 23.5"S.
For Example - · Columbia (near) equator, has about 1400 species of birds,
- · while New York (41◦N) and Greenland (71°N) have 105 and 56 species only.
- · A forest of tropical regions, like Ecuador, has ten times more species of vascular plants as in the forest of temperate region, like mid-west USA.
- · Amazon rain forest of, S. America, has the greatest biodiversity on earth, And has about 30.000 species of fishes, 1300 species of birds, about 400 each of amphibians, Reptiles and mammals, and 1,25,000 species of invertebrates. There are about 2 million species of insects and about 40,000 species of plants.
2. Altitudinal Gradient The impact of altitude is significant on type of biodiversity. Mostly the increasing altitude leads to decrease in only biodiversity as only some species can adapt the conditions prevailing at high altitude.
Following graph gives the clear idea this relationship
3. Species -Area relationship
The German naturalist and geographer, Alexander Von Humboldt, while exploring SouthAmerican jungles, observed that species - richness increased with increasing explored area, but only up to a limit.
This relationship between species richness and explored area is a rectangular hyperbola described by the equation - S = C Az
Where
S is species richness
C is Y-intercept A is area and z is the slope to the line ( regression coefficient). .
On logarithmic scale, the relationship is a straight line, described by the equation - Log S=Log C+Z log A
Ecologist have discovered that value of ‘Z’ always lies in the range of 0.1 to 0.2, irrespective of the taxonomic group (angiosperms, fish or bird), or the region /geographical area.
But if we consider a large area (i.e., whole continent) , the Z-value in the range of 0.6 to 1.2)
RELATIONSHIP BETWEEN SPECIES DIVERSITY AND ECOSYSTEM
Most of the ecologists believe that
- The communities with more species are more stable than those with lesser species.
- The stable community means lesser variations in productivity from year to year.
- The community with more species, is more resistant to occasional (natural or man-made) disturbances.
- Such communities are resistant to invasions by alien or exotic species.
Loss of BiodiversityThere is continuous loss of the earth' treasure of species. For example, the colonization of tropical pacific Islands by human has led to extinction of more than 2000 species of native birds.
The Red list of lUCN documented the extinction of 784 species in last 500 years. The last 20 years witnessed the disappearance of 27 species.
Some important examples of recent extinctions are
Dodu (Mauritius), Quagga (Africa), Thylacine (Australia). Steller Sea-cow (Russia), and subspecies of Tiger, like bali, javan and caspian.
- Presently, more than 15,500 species world-wide are facing the threat of extinction.
- This includes 32% of amphibian species, 23% of mammalian species and l2% of birds’ species.
- About 31% of the gymnosperms species are also facing the extinction. The amphibians are however,more vulnerable in such cases.
The ecologists now warn that-in next l00 years about 50% of all the species on earth will be wiped out. The loss in biodiversity of a region leads to
1. Lowered resistance to environmental changes
2. Decline in the plant production
3, Increased variability in certain ecosystem, pest disease cycles and water use etc.
Causes of loss of Biodiversity
The accelerated rate of species-extinction is largely due to human activities. There are 4-major causes, called ‘The Evil Quartet’, for the loss of biodiversity -
l. Habitat loss and fragmentation
2. Overexploitation
3. Invasion of Alien or exotic species
4. Co-extinctions
- Habitat loss and fragmentation
The tropical rain forest is the example of the habitat loss where forest covering has been reduced from 14% of land surface to 6%.
The Amazon rain forest, called ‘The Lungs of the Planet ', which harbors millions of species, is being cleared for cultivating soybean or developing grasslands for raising cattle. The pollution is also the factor for degradation of habitat.
When large habitats are broken into small fragments due to various human activities, the population of migratory animals, mammals and birds, that require a large territory, are adversely affected.
- Overexploitation
- ecology, overexploitation describes one of the five main activities threatening global biodiversity. Overexploitation can lead to resource destruction, including extinctions. Many marine fishes are also being over harvested. Over fishing from a water body, or over harvesting a product is
- Invasion of Alien or exotic species
For example –
- Introduction of Nile perch into lake Victoria (E. Africa) led to the extinction of more than 200 species of Cichlid fish in the lake
- Introduction of weed species, like Carrot grass (Parrhenium), Lantana and water hyacinth (Eicchornia) has posed threat to the native species and damage to environment.
- The illegal introduction of African cat fish (Clarias gariepinus) for aquaculture purposes into the river has threatened indigenous cat fishes.
- Co-extinctions
Process of extinction of biodiversity
1. Natural extinction -
With the change of environmental conditions some species have disappeared and the more adaptive species have appeared. This extinction is slow and is called ‘Background extinction’.
2. Mass extinction –
lt is extinction of large number of species due to natural calamities/catastrophes. The extinction of Dinosaurs is one such example.
3. Anthropogenic extinction -
It is the disappearance of species due to human activities. This man-made extinction represents a severe depletion of biodiversity in terms of time. The current rate of extinction is thousand times higher than the background extinction.
If the current rate of losses continues the earth may lose up to 50% of the species by the end of 2 l “Century.
Susceptilibility to extinction -
The species with the following features are more susceptible (vulnerable) to extinction than the other species.
l. Larger body size (eg. Elephant, Bengal Tiger and Lion etc.)
2. Smaller population with low reproductive rate (eg. Blue whale and Giant panda)
3. Fixed habitat or migratory routes (eg. Whooping cranes and Blue whales).
4. Feeding at higher trophic level in the food chain, (eg. Bengal tiger and Bald Eagle).
5. Narrow range of distribution (eg. Island species and woodland caribou).
Conservation of Biodiversity:
Biodiversity is being depleted by the loss of habitat, fragmentation of habitat, over exploitation of resources, human sponsored ecosystems, climatic changes, pollution invasive exotic spices, diseases, shifting cultivation, poaching of wild life etc.
Since the human beings are enjoying all the benefits from biodiversity, they should take proper care for the preservation of biodiversity in all its form and good health for the future generation i.e., the human being should prevent the degradation and destruction of the habitats thereby maintaining the biodiversity at its optimum level.
Conservation of biodiversity is protection, upliftment and scientific management of biodiversity so as to maintain it at its threshold level and derive sustainable benefits for the present and future generation. In other words, conservation of bio-diversity is the proper management of the biosphere by human beings in such a way that it gives maximum benefits for the present generation and also develops its potential so as to meet the needs of the future generations.
Mainly the conservation of biodiversity has three basic objectives:
(a) To maintain essential ecological processes and life supporting systems.
(b) To preserve the diversity of species.
(c) To make sustainable utilisation of species and ecosystems.
Strategies for Conservation of Biodiversity:The following strategies should be undertaken in order to conserve biodiversity:
(1) All the possible varieties (old or new) of food, forage and timber plants, live stock, agriculture animals and microbes should be conserved.
(2) All the economically important organisms in protected areas should be identified and conserved.
(3) Critical habitats for each species should be identified and safeguarded.
(4) Priority should be given to preserve unique ecosystems.
(5) There should be sustainable utilisation of resources.
(6) International trade in wild life should be highly regulated.
(7) The poaching and hunting of wildlife should be prevented as far as practicable.
(8) Care should be taken for the development of reserves and protected areas.
(9) Efforts should be made to reduce the level of pollutants in the environment.
(10) Public awareness should be created regarding biodiversity and its importance for the living organisms.
(11) Priority should be given in wildlife conservation programme to endangered species over vulnerable species and to vulnerable species over rare species.
(12) The habitats of migratory birds should be protected by bilateral and multilateral agreement.
(13) The over exploitation of useful products of wild life should be prevented.
(14) The useful animals, plants and their wild relatives should be protected both in their natural habitat (in-situ) and in zoological botanical gardens (ex-situ)
(15) Efforts should be made for setting up of National parks and wild life sanctuaries to safeguard the genetic diversity and their continuing evolution.
(16) Environmental laws should be strictly followed.
In-situ conservation is on site conservation or the conservation of genetic resources in natural populations of plant or animal species, such as forest genetic resources in natural populations of tree species.
It is the process of protecting an endangered plant or animal species in its natural habitat, either by protecting or cleaning up the habitat itself, or by defending the species from predators.
About 4% of the total geographical area of the country is used for in situ conservation. The following methods are presently used for in situ conservation.
It is the process of protecting an endangered plant or animal species in its natural habitat, either by protecting or cleaning up the habitat itself, or by defending the species from predators.
About 4% of the total geographical area of the country is used for in situ conservation. The following methods are presently used for in situ conservation.
Ex-Situ Conservation:Ex-situ conservation is the preservation of components of biological diversity outside their natural habitats. This involves conservation of genetic resources, as well as wild and cultivated or species, and draws on a diverse body of techniques and facilities. Such strategies include establishment of botanical gardens, zoos, conservation strands and gene, pollen seed, seedling, tissue culture and DNA banks.
i. Seed gene bank:
These are cold storages where seeds are kept under controlled temperature and humidity for storage and this is easiest way to store the germ plasma of plants at low temperature. Seeds preserved under controlled conditions (minus temperature) remain viable for long durations of time.
ii. Gene bank:
Genetic variability also is preserved by gene bank under normal growing conditions. These are cold storages where germ plam are kept under controlled temperature and humidity for storage; this is an important way of preserving the genetic resources.
iii. Cryopreservation:
This is the newest application of technology for preservation of biotic parts. This type of conservation is done at very low temperature (196°C) in liquid nitrogen. The metabolic activities of the organisms are suspended under low temperature, which are later used for research purposes.
iv. Tissue culture bank:
Cryopreservation of disease free meristems is very helpful. Long term culture of excised roots and shoots are maintained. Meristem culture is very popular in plant propagation as it’s a virus and disease free method of multiplication.
v. Long term captive breeding:
The method involves capture, maintenance and captive breeding on long term basis of individuals of the endangered species which have lost their habitat permanently or certain highly unfavorable conditions are present in their habitat.
vi. Botanical gardens:
A botanical garden is a place where flowers, fruits and vegetables are grown. The botanical gardens provide beauty and calm environment. Most of them have started keeping exotic plants for educational and research purposes.
vii. Animal Translocation:
Release of animals in a new locality which come from anywhere else.
Translocation is carried in following cases:
1. When a species on which an animal is dependent becomes rare.
2. When a species is endemic or restricted to a particular area.
3. Due to habit destruction and unfavorable environment conditions.
4. Increase in population in an area.
viii. Zoological Gardens:
In zoos wild animals are maintained in captivity and conservation of wild animals (rare, endangered species). The oldest zoo, the Schonbrumm zoo which exists today also, was established in VIENNA in 1759.
In India, the 1st zoo came into existence at BARRACKPORE in 1800. In world there are about 800 zoos. Such zoos have about 3000 species of vertebrates. Some zoos have undertaken captive breeding programmes.
Advantages of ex-situ preservation:
1. It is useful for declining population of species.
2. Endangered animals on the verge of extinction are successfully breeded.
3. Threatened species are breeded in captivity and then released in the natural habitats.
4. Ex-situ centres offer the possibilities of observing wild animals, which is otherwise not possible.
5. It is extremely useful for conducting research and scientific work on different species.
i. Seed gene bank:
These are cold storages where seeds are kept under controlled temperature and humidity for storage and this is easiest way to store the germ plasma of plants at low temperature. Seeds preserved under controlled conditions (minus temperature) remain viable for long durations of time.
ii. Gene bank:
Genetic variability also is preserved by gene bank under normal growing conditions. These are cold storages where germ plam are kept under controlled temperature and humidity for storage; this is an important way of preserving the genetic resources.
iii. Cryopreservation:
This is the newest application of technology for preservation of biotic parts. This type of conservation is done at very low temperature (196°C) in liquid nitrogen. The metabolic activities of the organisms are suspended under low temperature, which are later used for research purposes.
iv. Tissue culture bank:
Cryopreservation of disease free meristems is very helpful. Long term culture of excised roots and shoots are maintained. Meristem culture is very popular in plant propagation as it’s a virus and disease free method of multiplication.
v. Long term captive breeding:
The method involves capture, maintenance and captive breeding on long term basis of individuals of the endangered species which have lost their habitat permanently or certain highly unfavorable conditions are present in their habitat.
vi. Botanical gardens:
A botanical garden is a place where flowers, fruits and vegetables are grown. The botanical gardens provide beauty and calm environment. Most of them have started keeping exotic plants for educational and research purposes.
vii. Animal Translocation:
Release of animals in a new locality which come from anywhere else.
Translocation is carried in following cases:
1. When a species on which an animal is dependent becomes rare.
2. When a species is endemic or restricted to a particular area.
3. Due to habit destruction and unfavorable environment conditions.
4. Increase in population in an area.
viii. Zoological Gardens:
In zoos wild animals are maintained in captivity and conservation of wild animals (rare, endangered species). The oldest zoo, the Schonbrumm zoo which exists today also, was established in VIENNA in 1759.
In India, the 1st zoo came into existence at BARRACKPORE in 1800. In world there are about 800 zoos. Such zoos have about 3000 species of vertebrates. Some zoos have undertaken captive breeding programmes.
Advantages of ex-situ preservation:
1. It is useful for declining population of species.
2. Endangered animals on the verge of extinction are successfully breeded.
3. Threatened species are breeded in captivity and then released in the natural habitats.
4. Ex-situ centres offer the possibilities of observing wild animals, which is otherwise not possible.
5. It is extremely useful for conducting research and scientific work on different species.