ENVIRONMENTAL STUDIES Effective from Academic Session … › docs › EVS SEMESTER III(UNIT-1TO4)2016.pdf · 1.5 Environmental overexploitation and sustainable development. Unit

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ENVIRONMENTAL STUDIES

Effective from Academic Session 2015 and onwards

UNIVERSITY OF KASHMIR

COURSE MATERIAL

Compiled & Prepared by

Dr. Mubashir Jeelani

Department of Environmental Sciences, GDC Bemina Srinagar

According to the Syllabus-2016

2ND Year (Semester IIIrd )

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PRELIMINARY

Keeping in view the prevailing conditions in the valley and the huge loss to the academics of the

students there-from, the Higher Education Department of J&K along-with the University of

Kashmir has initiated the process of uploading instructional/study material in a bid to provide

partial respite to the distressed undergraduate students of the valley. This move has been initiated

with the view to compensate the academic loss by engaging the students through e-learning

process.

The study/course material of environmental studies Effective from Academic Session 2015 and onwards

and According to the Syllabus-2016 2ND Year (Semester IIIrd) for the academic session-2016 conforms to

the guidelines set in the meeting held at A.S. College Srinagar Kashmir on 06-10-2016. Emphasis has

been laid on the view that the entire syllabus gets covered, which lay a foundation for the learners to

enable them in learning the course.

As all the educational institutions including degree colleges across the Kashmir valley for the last

more than three months are closed, so emphasis has been laid on providing the students with e-

learning in full support to combat the loss created due to the unrest in the valley. In this back

drop,e-lectures have been prepared to engage the students in e-learning process. Although the

study material allows the learner to learn at his/her place but exploratory and hands-on activities,

discussions, opinions and experiments can’t be compensated by e-learning. This mode of

learning can’t be a substitute or alternative to class work.

Meanwhile the students are encouraged to seek further information from their teachers so that

active participation is fostered.

DATED: 25/10/2016 (Srinagar Kmr)

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Course Preparation Team

Unit-I:

Prof. Aijaz Qureshi (A/P)

Government Women’s College, M. A. Road Srinagar Kashmir

Unit-II:

Dr. Showkat Subhan (A/P)

Government Degree College Women’s Sopore Kashmir

Unit-III:

Dr. Pervez Ahmad (A/P)

Government Degree College Tangdhar Kashmir

Unit-IV:

Dr. Abdul Qayoom (A/P)

Government Degree College Pulwama Kashmir

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Syllabus for BA/B.Sc./B.Com./B.Sc.IT/BBA/BCA/B.Tech./B.Pharma/BBA-MBA/OC &

MIL 2nd Year (Semester-III)

Subject: Environmental Studies

Effective from Academic Session 2015 and onwards

Unit 1: Understanding Environment

1.1 Environment: Concept and importance.

1.2 Components of Environment: Physical, Biological and Social.

1.3 Concept of ecological balance in nature.

1.4 Environment and human health.

1.5 Environmental overexploitation and sustainable development.

Unit 2: Ecosystems

2.1 Concept of an Ecosystem.

2.2 Structure of an ecosystem.

2.3 Concept of food chain, food webs and ecological pyramids.

2.4 Energy flow in an ecosystem.

2.5 Characteristic features of a terrestrial ecosystem and an aquatic ecosystem.

Unit 3: Natural Resources

3.1 Land resources: Global land use patterns, concept of waste land reclamation and

Desertification.

3.2 Forest resources: Use and consequences of over-exploitation.

3.3Water resources: Use and consequences of over-utilization, concept of water harvesting and

watershed management.

3.4 Food resources: World food problems and concept of sustainable agriculture.

3.5 Energy resources: Renewable and non renewable energy sources.

Unit 4: Biodiversity and its Conservation

4.1. Biodiversity: meaning levels and values (commercial, ecological, social and aesthetic).

4.2 Threats to the biodiversity: Habitat loss, poaching of wildlife, man-wildlife Conflicts.

4.3 Concept of endemic and exotic species.

4.4 Conservation of biodiversity: In-situ and Ex-situ.

4.5 Hot spots of biodiversity.

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UNIT I: UNDERSTANDING ENVIRONMENT

1.1. ENVIRONMENT:

CONCEPT AND IMPORTANCE

Definition: Environment is the complete range of external conditions under which an organism

lives including physical, chemical and biological components of the environment.

Concept of Environment:

➢ It gives us the understanding of the interrelationships between plants, animals, microbes

(biotic) and air, water, soil, temperature (abiotic) components.

➢ It gives us the understanding of the multidisciplinary nature of the environment.

➢ It involves the studies of air, water, soil, plants, animals, microbes all are the basic

components (biotic and abiotic) which legitimize the humans to know about their

environment.

➢ The concept also introduces us to various issues associated with our surroundings.

➢ The concept of environment and its studies provides us the understanding of water, air

and soil pollution, climate, quality of life, global warming, earthquakes, geology,

geography etc.

➢ The concept also gives us an experience of monitoring our surroundings and making

assessment of the impacts of changes in environmental conditions.

➢ The concept also gives us the ability to provide managerial practices.

➢ Along with Physics, Chemistry, Geology, Atmospheric Science, Geography branches,

Mathematics, Statistics, Computer Sciences also help in modeling and management of

environment.

➢ Other subjects like Economics, Sociology and Education do help in understanding the

socio-economic aspects of environment.

Importance of Environment

The environmental study is helpful in solving many problems and also helps in understating the

fundamental relationship of the natural community. The study of environmental sciences is

important as it aims for the following:

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1) In solving environmental problems like:

a. Pollution.

b. Depletion of Ozone layer.

c. Depletion of biodiversity.

d. Global warming.

e. Reducing energy resources.

f. Impact of mining and hydro electric projects.

g. Solid waste management.

h. Energy crisis.

2) Environmental studies are helpful in:

a. Sustaining life support system.

b. Hygenic living conditions and clean drinking water.

c. Town planning.

d. Location of industries.

1.2 COMPONENTS OF ENVIRONMENT

a) Physical or abiotic

Air

Water Abiotic

Land

b) Biological or biotic

Plants

Animals Biotic

Microbes

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c) Social

This includes the social conditions such as historical, economical, moral, cultural and politics

that affect the nature of an individual or community.

1.3 CONCEPT OF ECOLOGICAL BALANCE IN NATURE

➢ The term ecosystem was first coined by British ecologist A.G.Tansley in 1935 and

the term ecosystem was defined by him as “the system resulting from the integration

of all the living and non living factors of the environment”.

➢ The word Ecology comprises of two components- organism and environment. The

components are complex, dynamic and interdependent and are mutually reactive and

interrelated.

➢ The functioning of any system involves a series of cycles e.g. hydrological cycle and

the cycles of various nutrients and are driven by energy flow (solar energy).

➢ The continuation of life demands constant exchange and return of nutrients to and

from the different components of ecosystem.

➢ Therefore, the concept of ecosystem is and should be broad one and its maintenance

should emphasis obligatory relationships, interdependence, and casual relationships

i.e. coupling of components from functional point of view.

➢ According to Palmisana (1977) the recent system of ecosystem characterization may

be defined as a description of various processes and components comprising an

ecosystem and an understanding of their functional relationships.

➢ The above definition describes the important ecosystem components and functional

processes, besides providing a mechanism undertaken through integration of

components and functions.

➢ So, such an approach helps in:

a) Integration of complex ecological information.

b) Identification of gaps and lack in information.

c) Assessment of environmental impact and comprehensive explaining.

➢ Thus, the ecosystem characterization is one of the important tools needed to manage

and protect living resources.

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➢ One of the universal character of all the ecosystems, whether aquatic or terrestrial is

the integration of autotrophic and heterotrophic components.

1.4 ENVIRONMENT AND HUMAN HEALTH

Human health is directly related to environment. The physical characteristics of the globe have

determined his diet and hence his health. The relationship between human health and his

environment are interrelated. There are many ways in which the environment effects human

health. Some of them are as follows:

➢ Direct discharge of pollutants by industries into the air and water.

➢ In urban areas, current disease pattern is closely linked to the deterioration in the quality

of air and water.

➢ Human health is also influenced by quality of environment in the place of work.

➢ It has been recognized that the workers in certain occupations such as textile mills or

stone quarries suffer from occupational diseases.

➢ Deterioration of the environment such as existence of stagnant pools in villages and

cities.

➢ Many diseases carrying vectors have developed immunity to pesticides. As a result

malaria has reached endemic proportions to many parts of the country.

➢ Similarly diseases like Kala-azar are difficult to eradicate as the organisms spreading it

find increasing number of breeding places.

➢ Overcrowding, unhygienic conditions in cities, particularly in slums, have also

contributed to the spread of other communicable diseases such as tuberculosis and

cholera.

There are a number of many other factors manifested by the human activities which are

responsible for cause of health problems like:

• Noise pollution

• Radiations.

• Indoor air pollution like

Tobacco smoke.

Fuels used for cooking and heating.

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Poorly ventilated rooms or rooms are covered to retain heat in the winter

months.

Levels of economic conditions of every house hold

➢ Health interventions become almost meaningless so long as much conditions prevail.

It has become more clear that “improving environmental conditions should form an

important part of healthcare because curative care alone will not suffice as more succumb to

these diseases”.

1.5: ENVIRONMENTAL OVEREXPLOITATION AND SUSTAINABLE

DEVELOPMENT

ENVIRONMENTAL OVEREXPLOITATION:

Nature has given us abundant resources in the form of water, air, vegetation, soil, wild animals,

metals, fossil fuels etc. These are the free gift to the mankind. Men are using all these resources

in some way or the other right from the dawn of civilization. Thus, utilization of resources, has

improved the development of any country or a region. In the course of the operation of natural

resources, man has ill-used its availability, thus affecting the natural ecosystem. Instead of

improving his living conditions, he has created major long-term problems and has been

catastrophic for the natural environment.

a) Overexploitation of Forest Resources

➢ The total forest area of the world in 1900 was about 7000 million hectares which

reduced to 2,890 Mha by 1975.

➢ According to one estimate, all tropical forests of the world would probably

disappear in the next 50 to 70 years, if the present rate of deforestation continues

unabated.

➢ Although, national policy laid down in 1952 considered 33% of forest cover of

only about 22.7% and the loss of our forest wealth continues at the rate of about

1.3 Mha per year.

➢ Deforestation is a consequence of over-exploitation of forest resources for space,

energy and materials.

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➢ Expansion of agriculture is one of the prime causes of deforestation. As demands

on agricultural products rise, more and more land is brought under cultivation at

the cost of forests.

➢ Shifting cultivation also results in destruction of forests or deforestation.

➢ The deforestation leads to chain of consequences notably

1. Change in climatic conditions

2. Degradation and erosion of soil

3. Economic loses and

4. Loss of biological diversity.

b) Overexploitation of Water Resources

➢ The ill effects of withdrawal of more water than the total annual input may be

drastic.

➢ . Over exploitation of ground water has resulted in receding of water table by several

metres in many parts of the world.

➢ The rapid rise in demand for fresh water is naturally the result of rapid growth in the

number of consumers and non -judicious use of this limited resource.

➢ Most of our surface water resources have become polluted and unfit for human use

because of large quantities of domestic sewage and industrial effluents disposed into

these water bodies.

➢ Deforestation besides over exploitation has been an important factor for the

depletion of underground water resources.

➢ Unless there is balance between water drawn from the water table and the inputs the

underground water table recedes deeper and deeper.

c) Land degradation

➢ Land degradation is damage to land that makes it less economically useful and less

biologically diverse.

➢ This term is used specifically to refer to damages caused by human activities

rather than natural ones and human activities can indirectly contribute to environmental

changes that may accelerate the speed of land degradation.

➢ People think of land degradation as a new thing, but it has been happening ever

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since people started farming the land.

➢ Or at least since they started using irrigation which can cause all kinds of trouble

even if it seems like it would be fairly harmless.

➢ Farmland is prone to land degradation factors in India and covers about 600

million hectares.

➢ The main factors responsible for soil degradation are:

a) Soil erosion.

b) Salinization

c) Soil contamination.

d) Air Pollution

Air being very vital component of earth‘s environment which forms the basic of the diversity of

life on this planet, slight change in its composition can have varied effects on the survival of the

life.

➢ The presence of certain substances in air beyond those concentration levels that can

lead adverse effects on biotic as well as abiotic environmental factors is termed as air

pollution.

➢ Agricultural activities including the use of various pesticides pollute the air while

spraying of weedicides, insecticides and fungicides etc. The fumes are released into the

air and cause pollution.

➢ There are varied and diverse effects of various pollutants in air on the biotic as well

as abiotic environment.

➢ All the components of air, beyond the optimum levels cause damage to plants,

animals, human beings and the abiotic environment.

➢ Some of the major, integrated effects on air pollution in general are as follows

1. Increased higher concentration of green house gases in air (e.g. CO2, CH4, NO2, SO2,

CFC‘s, water vapour etc) have caused increase in average global temperature (Global

warming) which can lead to serious consequences.

2. Depletion of ozone layer by CFC‘s is yet another serious effect of air pollution. It was led

to increased inflow of ultraviolet radiations reaching the earth‘s surface which can lead

serious health hazards in humans and animals. Constant exposure can damage the

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vegetation as well.

3. Acid rain is another consequence of air pollution. Gases like oxides of carbon; Sulphur,

nitrogen etc combine with water and fall down as acid rain which causes damage to

flora, fauna and abiotic structural assets like historical monuments etc. The effects are

more pronounced in aquatic systems.

4. Carbon monoxide proves to be fetal even in small concentrations as it blocks hemoglobin

for binding of oxygen and reduces the oxygen carrying capacity of blood.

5. Increased ozone concentration in air can lead to pulmonary edema. It along with

aldehydes irritates eyes and respiratory organs. Air pollution leads to many respiratory

diseases including bronchitis and asthma due to the presence of particulate and

irritating gasses.

6. Lead and other metallic particulates have adverse effects on various physiological and

biochemical processes of organisms. Fluorides cause glurosis in animals.

7. Crops are adversely affected by increased concentrations of oxides of sulphur, nitrogen,

ozone etc

SUSTAINABLE DEVELOPMENT

Sustainability means the ability to last and resist depletion. G.H. Brundtland (1987), defined

sustainable development as “meeting needs of the present generation without compromising the

ability of future generations to meet their own needs”. United Nations Environment Programme

(UNEP) and World Wildlife Fund (WWF) laid down nine principles for sustainable

development:

1. Minimize depletion of non-renewable resources.

2. Conservation of earth’s vitality and diversity.

3. Change of personal attitudes and practices.

4. Improve the quality of life-supporting systems of the earth.

5. Keep the population within the carrying capacity of the earth.

6. Enable communities to care their own environment.

7. Respect and care for other communities.

8. Create a global alliance.

9. Provide framework for development and conservation.

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➢ Two aspects of sustainable development:

• Inter generational equality.

• Intra generational equality.

➢ Steps for sustainable development:

• Three R approach should be followed which states:

• Reduce.

• Reuse.

• Recycle.

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UNIT 2: ECOSYSTEMS

2.1 Concept of an ecosystem.

The term ecosystem was proposed by the British ecologist A.G.Tansley in 1935, but the concept

of the unity of organisms and environment can be traced back to very early biological literature.

In 1877 Karl Mobius used term ‘biocoenosis’ and in 1887 S.A.Forbes used the term ‘microcosm’

for different types of ecosystems.The concept of ecosystem is a very broad one and emphasizes

the obligatory relationships, the casual relationship and the interdependence of biotic and abiotic

components.

E.P.Odum a renowed ecologist stated that the ecosystem is the basic functional unit of organisms

and their environment, interacting with each other and within their own components.

An ‘ecosystem’ is a region with a specific and recognizable landscape form, such as a forest,

grassland, desert, wetland or coastal area. Thus the definition of any ecosystem can be said as the

living environment such as soil, air and water- constitute the ecosystem.

2.2: Structure and function of an ecosystem.

2.2.1: Producers, consumers and decomposers.

An ecosystem has two components-the biotic components, consisting of living things, and the

abiotic portion, consisting of elements that are not alive. The non-living constituents are said to

include the following categories: habitat, gases, solar radiation, temperature and moisture,

inorganic and organic nutrients. The living organisms include plants, animals and decomposers

according to their specific role in keeping the ecosystem operating as a stable interacting whole.

The function of an ecosystem reveals us how the energy flow takes place in the system by

studying food chains, food webs, ecological pyramids and interaction of producers, consumers

and decomposers.

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Every biotic components (living organisms) need food for growth and development. Thus every

living organism is in some way dependent on other organisms. From a structural view point three

biotic components have been recognized:

(a) Producers: The producers are the autotrophic organisms, chiefly green plants, that utilize

radiant energy to manufacture food from simple inorganic substances like water, Co2, salts etc.

Plants take energy from the non-living environment and make it available to all living organisms

and for themselves. They convert the light energy of the sun into chemical energy in the form of

organic compounds.

(b) Consumers: Consumers are heterotrophic organisms (primarily animals) and are either

directly or indirectly dependent upon autotrophs for food. The herbivores remain dependent upon

the green plants for their food and are the primary consumers. However, the primary consumers

also vary with the kind of the ecosystem. Elton(1939) gave the name “key industry animals” to

the herbivores because life of other prominent animals of a community depends upon these

herbivores. The herbivores are used as food for primary carnivores or secondary consumers.

(c) Decomposers: Like consumers, the decomposers are the heterotrophic organisms. They feed

on dead protoplasm, breaking down its complex organic components of cells from dead

producers and consumer organisms either into small organic molecules, which they utilize

themselves as saprophytes or into inorganic substances that can be used as raw materials by

green plants. Thus, the continous functioning of an ecosystem hinges on the activity of

decomposers in recycling of organic matter and are mostly bacteria and fungi.

2.2.2: Food chains, food webs and ecological pyramids.

Organic nutrients (energy) are transferred from producers to consumers and decomposers as

organisms eat and in turn are eaten by other organisms. This succession is called a food chain.

The food chain is divided into trophic levels comprised of all the organisms that obtain their food

by an identical number of steps.

Sun/CO2

/H2O

Green

Plants/vegetables

Sheep/Goat/Human Wolf/Human Tiger

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The producers (autotrophs) comprise the first trophic level. The herbivores comprise the second

trophic level and the carnivores that consume the herbivores constitute the third trophic level.

The carnivores which consume third level carnivores comprise the fourth trophic level and so on.

All food chains begin at the producer level and all end at the decomposer levels.

During transfer of energy from one trophic level to another some energy is always dispersed into

unavailable heat energy and is never 100% efficient. The shorter the food chain or nearer is the

organism to the beginning of the food chain, the greater is the available food energy.

In most ecosystems, many different food chains are possible and these overlap and are

interwined with one another to form what is called a community food web. Food web is simply a

diagram of all the trophic relationships among and between its component species. A food web is

generally composed of many food chains, each of which represents a single pathway up to the

food web. Thus, the population within the food web is linked by the various food chains through

which organic nutrients are transferred. The alternate pathways in a food web help to maintain

stability of the living community.

The greater the number of alternate pathways a food web has, the more stable is the community

of the living things which make up the web.

2.2.3: Ecological Pyramids

An ecological pyramid is a sort of geographical representation showing relationships between

the various trophic levels of a community. Ecological pyramids are of three general types.

(a). pyramid of numbers

(b). pyramid of biomass

(c). pyramid of energy

(a). pyramid of numbers: This type of pyramid shows the number of individual organisms at

each trophic level. In most of the ecosystems this type of pyramid shows upright structure

meaning the number of individuals goes on decreasing from base to apex. In a forest ecosystem

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however, the pyramid of number is somewhat different in shape. The producers which are

mainly large sized trees are lesser in number and form the base of the pyramid. The herbivores,

which are the fruit eating birds, elephants, deer etc are more in number than the producers. Then

there is a gradual decrease in the number of successive carnivores, thus making the pyramid

again upright. However in a parasitic food chain the pyramids are always inverted.

(b). pyramid of biomass: They are comparatively more fundamental, as they instead of

geometric factor, show the quantitative relationships of the standing crops. The pyramid of

biomass in grassland and forest are upright as there occurs a gradual decrease in biomass of

organisms at successive levels from the producers to the top carnivores. However in a pond, the

producers are small organisms their biomass is least and this value gradually shows an increase3

towards the apex of the pyramid, thus making the pyramid inverted in shape.

(c). pyramid of energy: Of the three types of ecological pyramids, the energy pyramid gives the

best picture of overall nature of the ecosystem. This type of pyramid represents the total amount

of energy utilized by different trophic level organisms of an ecosystem in unit area over a set

period of time. The pyramid of energy depicts the amount of energy flow to each successive

trophic level receives less total energy than the level below. So greater amount of energy is

available at the producer level and go decreasing in successive trophic levels, thus giving it

upright shape always.

2.3: Energy flow in an ecosystem

The ultimate source of energy in any type of ecosystem is the solar energy and this energy flows

from one organism to another in an ecosystem in a unidirectional manner.

Flow of energy in an ecosystem takes place through the food chain and it is this energy flow

which keeps the ecosystem going. The most important feature of this energy flow is that it is

unidirectional. Unlike the nutrients (like carbon, nitrogen, phosphorus etc.) which move in

acyclic manner and are reused by the producers after flowing through the food chain. The flow

of energy in an ecosystem follows the two laws of thermodynamics:

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1st Law of Thermodynamics states that energy can neither be created nor be destroyed but it can

be transformed from one form to another. The solar energy captured by the green plants

(producers) gets converted into biochemical energy of plants and later into that of consumers.

2nd Law of Thermodynamics states that energy dissipates as it is used or in other words, it gets

converted from a more concentrated to dispersed form. As energy flows through the food chain,

there occurs dissipation of energy at every trophic level. The loss of energy takes place through

respiration, loss of energy in locomotion, running, hunting and other activities. At every level

there is about 90% loss of energy and the energy transferred from one trophic level to the other is

only about 10%.

The diagrammatic representation of energy flow in an ecosystem reveals how energy goes on

decreasing when passing from one tropic level to another.

2.4:Characteristic features of a/an;

2.4.1: Terrestrial Ecosystem.

2.4.2:Aquatic Ecosystem.

The characters and extent of community succession in a given area depends on climate and soil

conditions. The climax community is achieved only if environmental factors permit a full

sequence of seral stages. All ecosystems resemble each other in the sense that all have same

components, i,e autotrophic and heterotrophic, interacting upon each other thus bringing about

circulation of materials. In one ecosystem, the climate and soil conditions are relatively uniform

and they favour the growth of a certain kind of climax community.

2.4.1: terrestrial Ecosystem:

The seas are characterized by constancy, the lands by variability. The seas have always existed

and been connected where as land masses have been considerably shifted, both vertically and

horizontally. Terrestrial habitats are naturally quite different from the aquatic habitats. Most

aquatic organisms die relatively soon after being exposed to air. Water diffuses and evaporates

so quickly from their bodies that cellular metabolism is disrupted and then destroyed. The

conservation of water is therefore, a major problem for land organisms. Terrestrial animals and

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plants have special devices to conserve water. On land great variation in available water, ranging

from marshes at one extreme to waterless deserts at the other, determine the habitability of

particular land masses.

Important characteristic features of a terrestrial ecosystem which control and determine the

nature of all terrestrial ecosystems are abioticand biotic factors mentioned as below:

Abiotic components:

The ecosystems of the terrestrial environment are most variable. Factors having significant effect

on life are given as:

Soil:

The major life supporting element of the terrestrial environment is soil, composed of mineral

matter interspersed with varying qualities of organic substances, air and water. The fertility and

structure of soil in various regions determines the amount and type of vegetation. This in turn

determines the numbers and varieties of consumers within the ecosystem.

Water:

The body of all organisms is composed of about 60-70% of water, that is why water is a major

limiting factor in terrestrial life. Usually terrestrial organisms living in moist habitats freely

consume and excrete large amounts of water. In arid regions, all organisms are physiologically

adopted for conservation of water.

Temperature:

Temperature vary greatly on land, not only from place to place but also with the season. The

surface temperature in some deserts may fall for below 0oC in winter and rise above 50oC in the

summer. No organism in its active state, can withstand the entire range of environmental

differences encountered on land. Each species has evolved adaptations for life in a specific

ecosystem.

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Oxygen and Carbon dioxide:

Oxygen and Carbon dioxide are the only required substances in all terrestrial ecosystems that are

nearly constant in amounts. In air, oxygen is about 21% and carbon dioxide 0.032% by volume.

Both gases are vital requirements for two important processes i,e. photosynthesis and respiration.

Light:

Light is the most important factor for producers or autotrophs for their photosynthetic activities.

Consumers depend upon producers. Thus the requirement of light to living beings can be

understood. Light intensity, quality and quantity on the earth’s surface varies greatly which is

due to angle of incidence, degree of latitude, climate and various biological factors.

Geographical barriers:

Land has also got geographical barriers which check free movement and result in the

development of ecosystem, free from outside biotic forces.

Biotic components:

Biotic components include producers, consumers and decomposers as stated as under;

(a). Producers: The producers are the autotrophic organisms, chiefly green plants, that utilize

radiant energy to manufacture food from simple inorganic substances like water, Co2, salts etc.

Plants take energy from the non-living environment and make it available to all living organisms

and for themselves. They convert the light energy of the sun into chemical energy in the form of

organic compounds.

(b). Consumers: Consumers are heterotrophic organisms (primarily animals) and are either

directly or indirectly dependent upon autotrophs for food. The herbivores remain dependent upon

the green plants for their food and are the primary consumers. However, the primary consumers

also vary with the kind of the ecosystem. Elton (1939) gave the name “key industry animals” to

the herbivores because life of other prominent animals of a community depends upon these

herbivores. The herbivores are used as food for primary carnivores or secondary consumers.

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(c).Decomposers: Like consumers, the decomposers are the heterotrophic organisms. They feed

on dead protoplasm, breaking down its complex organic components of cells from dead

producers and consumer organisms either into small organic molecules, which they utilize

themselves as saprophytes or into inorganic substances that can be used as raw materials by

green plants. Thus, the continuous functioning of an ecosystem hinges on the activity of

decomposers in recycling of organic matter and are mostly bacteria and fungi.

On the basis of different biotic communities observed on different regions of terrestrial

ecosystems varying due to different abiotic conditions, there are different types of terrestrial

ecosystems mentioned below as:

*Coniferous forest ecosystem.

*Temperate deciduous forest ecosystem.

*Tropical rain forest ecosystem.

*Arctic ecosystem.

*Tundra ecosystem.

*Desert ecosystem.

4.2: Aquatic Ecosystem:

As 70% of the earth is covered by water, so aquatic ecosystem contribute much more as

compared to terrestrial ecosystem. Out of this 70% of water, 97% is marine water and 3% as

fresh water, which is (later) usable for human consumption and other agricultural activities etc.

The fresh water is available in the form of lakes, rivers, streams, ponds and wetlands and marine

water in seas and oceans.

There are two categories of freshwater ecosystems:

(a).Lentic water (standing) including ponds, lakes, wetlands.

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(b).Lotic water (running) including streams, springs and rivers. Fresh water ecosystems have low

percentage of dissolved salts. They have fluctuating physical and chemical factors affecting flora

and fauna.

These different types of aquatic ecosystems have different characteristic features as both abiotic

and biotic components vary from one system to another and even in same ecosystem they vary

from one season to another season. Here some major aquatic ecosystems are briefly discussed:

Of fresh water ecosystems, the lentic water (standing) habitats are generally divided into three

zones:

Example of Lake Ecosystem

(a). Littoral zone: This zone consists of bottom and shallow water areas where sunlight

penetrates. It is near the shore and contains the greatest number of different species. In littoral

zone producers are of two main types:

1. Rooted or benthic plants: e.g. water lilies, typha, ceratophyllum etc.

2. Phytoplankton or floating green plants e.g. algae and diatoms.

In this zone also the scene of the greatest concentration of animals distributed in

recognizable communities are.

*Freely swimming (nekton) e.g. beetles and bugs.

*Floating members (neuston) e.g. Protozoa and water striders.

*Vertebrates e.g. Frogs, salamanders, snakes etc.

*Decomposers are usually least clear.

(b). Limnetic or open water zone: As this zone is located in open water above the profundal

zone, so most of its inhabitants are microscopic. The production is limited to phytoplankton

including blue green and diatoms. One characteristic feature of limnetic zone producers is great

yearly fluctuations in population density. Consumers of this zone are mainly zooplankton

microscopic animals and fish.

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(c). Profundal or deep zone: Light does not penetrate in profundal zone and the inhabitants

have to depend on the other zones for food, hence no producers in this zone. Decomposers

(Bacteria and fungi) predominate in this zone. Consumers of profundal zone are blood worms,

annelids and other small animals capable of surviving in a region of little light and low oxygen.

The scientific study of lakes is known as liminology. On the basis of the amount of nutrition they

provide for fishes and other inhabitants, lakes are categorized into:

Eutrophic, Mesotrophic and Oligotrophic lakes.

*Eutrophic being shallow and rich in nutrients.

*Mesotrophic which are moderate in nutrient concentration.

*Oligotrophic being deep and relatively poor in nutrients.

Lotic waters:

Lotic waters are those which occur in fast running streams, springs, rivers etc. The biotic

communities in lotic waters are different from lentic waters due to differences in physical and

chemical conditions of their environments. Water currents, close association with surrounding

land areas, high oxygen concentration and ecological communities are adapted to such

conditions. In fast flowing water, the plants are usually submerged and are mainly made up of

algae and masses. The sandy bottom is occupied by burrowing aquatic animals such as worm

clams and insect larvae.

The abiotic components in both lentic and lotic water ecosystems comprise water, oxygen,

nitrogen, phosphorus, calcium, amino acids and humic acid etc. Producers take them in a small

amount in soluble form. Most of them remain inside the bodies of animals.

The Ocean Ecosystem

The oceans, which cover 70% of the earth’s surface, constitute one of the great reservoirs of

living things and of the essential nutrients needed by both land marine organisms. The average

depths of the oceans is roughly 4000 metres and life in oceans also depends upon light. The

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oceans are divided into several general regions depending on the light penetration and depth of

the bottom.

Neritic zone:

Most continents are surrounded by a continental shelf, a more or less flat plain under about 200

metres of water but in some places much less. The shelf itself and waters over the shelf

constitute the neritic zone. The part of neritic zone near shore up to 50mts. having enough light

penetration, favouringplant growth is termed littoral. The neritic zone can be further sub-divided

into supratidal, intertidal and subtidal regions.

Oceanic zone:

Beyond the neritic zone is the oceanic zone. The bottom slopes rapidly from the continental shelf

down to depth of 3000mts. and lower. The regions of these great depths are the abyssal regions.

No light ever penetrates this far. The temperature is virtually at abut 3oc. This part is called “blue

water”.

Euphotic zone:

The upper part of the ocean, into which enough light can penetrate to be effective in

photosynthesis, is known as the euphotic zone. The average lower limit of this is at about

100mts.

Abiotic components: In the marine environment, the most significant abiotic components

affecting the marine life are light, temperature, pressure, salinity, currents and tides.

Biotic components: Like other ecosystems the marine environment also has producers,

consumers and decomposers but the composition of these living organisms is different because

of different abiotic conditions and marine environment itself.

***********************************************************

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UNIT 3: NATURAL RESOURCES

Topic: Land Resource, global land use pattern

Objectives: To let the student know about

1. Availability of land resource

2. Importance of land resource

3. Pattern of land use

Land Resource:

Land is precious resource that forms the base for the emergence and development of all living

organisms including human beings. Out of total earth’s surface area about 29% is land and rest is

water. It measures about 13939 million hectares. Out of this available land resource throughout

the world, about 36.6% of the land area is covered by houses, factories, roads, railways deserts,

glaciers, mountains and polar ice marshes. About 30% of land is covered by forests and about

22% by meadows and pastures. Only about 11.4% of total land area is fit for tilling and crop

cultivation.

Importance of land resource: As stated above land forms the base for the emergence and

development of all living organisms. It is one of the most important components of life support

system. We use land for various purposes like agriculture, settlements, forestry and other

purposes including nature reserves for conservation. Therefore, we depend upon land resource for

our food, fibre, fuel and other basic amenities of life.

Definition/explanation of land use: Land use may be defined as the arrangements, activities and

inputs people undertake in a certain land cover type to produce, change or maintain it. Land use

denotes how human use the biophysical or the ecological properties of land.

Global land use pattern: Land use pattern include the modification and management of land for

agriculture, settlements, forestry and other uses including nature reserves for conservation. Since

all land is not equal, each section or region of the world has its own soil characteristics, climate,

degree of slope and geographical location. When these are all taken into consideration, a proper

land use can be determined for each portion of the planet earth. Therefore, the global pattern of

land use varies from place to place and country to country. At the same time wise planning of the

land is necessary to keep the land and its soil able to provide food and other necessities of life.We

know that only about 29% of earth’s surface is land and rest about 71% is covered with water.

Major portion of the land i.e. about 52% is under forest cover, pastures and meadows throughout

the world. Around 37% covered by houses, factories, roads, railways deserts, glaciers, mountains

and polar ice marshes. Rest is available for tilling and crop cultivation.

Land use pattern in India: India has a total land area of 2.4% of the world’s total. Of this about

43% of land surface is covered by plains, 28% by plateaus and less than 30% comprises

mountains and hills. Nearly 44% of land surface is used for agriculture, 11-14% is covered with

forests, 4% pastures and grazing lands and 8% is used for housing, establishment of industries,

roads and dams etc.

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What we learnt

1. Land as a resource: A precious resource that forms the base for emergence and development

of life. About 29% of the Earth’s surface is land and rest is covered with water.

2. Land use: The arrangements, activities and inputs people undertake in a certain land cover type

to produce, change or maintain it.

3. Land use pattern: The modification and management of land for agriculture, settlements,

forestry and other uses including nature reserves for conservation.

Topic: Land Degradation and wasteland reclamation

Objectives: To let the student know about

1. What is land degradation

2. Causes of land degradation

3. Concept of degraded/wasteland reclamation

Land degradation

Land degradation refers to loss of fertility or productive capacity of the soil. With increasing

population growth the demand for fertile land for cultivation food, fibre and fuel wood has

increased considerably. With the result there is over-exploitation of land resources resulting in

land degradation.

Causes of land degradation

Various physical and chemical factors are responsible for degradation of land resources. Physical

factors like water and wind cause soil erosion. Although soil erosion is a natural process, it is

aggravated due to felling of trees and overgrazing. Other physical factors like wrong methods of

cultivation, urbanisation, industrialization, construction of dams etc. contribute in degradation of

land. Among chemical factors salinization, acidification, and accumulation of toxic chemicals

cause land degradation.

Concept of Wasteland Reclamation

What are wastelands?

Wastelands are those lands which are for one reason or the other; do not fulfil their life

sustaining potential. Increasing misuse of land resources has resulted into wastelands.

Degradation of land occurs due to erosion, desertification, mining, water-logging, salinity and

toxic effects of agrochemicals and industrial effluents. Water logging and salinisation are the

major causes which convert fertile land into wasteland.

How to reclaim wastelands?

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There are a number of ways and means by which wasteland can be reclaimed for

productive purposes. Among them watershed management, wasteland afforestation and social

forestry programmes are noteworthy. Control of soil erosion and enhancement of soil fertility are

also important measures for improvement of land condition.

Deforestation for timber and fuel wood extraction and subsequent conversion of forest land

to agricultural or urban areas poses major threat for land degradation and also quicken the

process of wasteland formation. These factors are needed to be addressed properly in wasteland

reclamation process.

Examples of wastelands and their reclamation

1. Water logging

Water logging is caused due to over-irrigation of agricultural fields by farmers for good growth

of crops. Over-irrigation coupled with inadequate drainage results in excess accumulation of

underground water. It gradually forms a continuous column with the water table and the pore-

spaces in soil get filled with water. This results in depletion of soil-air and roots of plants do not

get adequate air for respiration. Crop yield falls as the soil strength declines and plants get

lodged.

Reclamation of water logged soils

Reclamation of water logged soils can be achieved by preventing over-irrigation and subsurface

drainage technology. Specific tree plantation is bio-drainage method to reclaim water logged

soils.

2. Salinisation

Salinasation of soils is one of the major causes of land degradation in the world. About one third

of the cultivable land area in the world is affected by salts. A major cause of salinisation is

excessive irrigation. Different kinds of salts get accumulated in the soil profile. pH of such soils

usually exceeds 8.0. Salinity causes stunted plant growth and lowers crop yield. Most of the

crops cannot tolerate high salinity.

Reclamation of saline soils

The most effective method to remove slats from saline soils is to flush them out by applying

good quality water. Another method is laying underground network of perforated drainage pipes

for flushing out slats slowly.

Sub-Topic: Desertification

Objectives: To let the student know about

1. What is desertification

2. Causes of desertification

3. Extent of desertification

4. Control of desertification

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Desertification

Desertification is a process in which the productive potential of land in arid and semi-arid areas

of the world drops by 10% or more. Moderate desertification is 10-25% drop in productivity,

severe desertification causes 25-50% drop and very severe desertification results in more than

50% drop in productivity of land. Desertification is characterized by loss of vegetation cover,

depletion of ground water, salinisation and severe erosion.

Causes of Desertification: Formation of deserts may take place due to climate change, soil

erosion or may be due to abusive land use practices. Major causes responsible for desertification

include:

a. Deforestation: Loss of vegetation cover increases soil erosion, loss of fertility and loss of

water. Thus deforestation initiates desertification.

b. Overgrazing: The regions more seriously affected by desertification are the cattle

producing areas of the world. Increasing cattle population graze heavily in grasslands and

forests which in turn get dry and denuded. The dry denuded land becomes loose and more

prone to erosion and thus plant growth is badly hampered leading to further

desertification.

c. Mining and quarrying: These activities are also responsible for loss of vegetal cover

and denudation of extensive land areas leading to desertification.

Extent of desertification

During the last 50 years about 900 million hectares of land have undergone desertification.

Amongst the most badly affected areas are the sub- Saharan Africa, the Middle East, Western

Asia, parts of Central and South America, Australia, and the western half of the United States.

Control of desertification

Some of the important measures to control desertification are:

1. Reforestation of denuded and overgrazed areas.

2. Reclamation of abandoned mines by landscaping and reforestation.

3. Better agricultural practices like terracing and contour farming to check soil erosion.

4. Crop rotation and multiple cropping should be adopted to maintain soil fertility

What we learnt

Land degradation: Land degradation is the loss of fertility or productive capacity of the soildue to various factors like soil erosion,

deforestation, overgrazing, water logging, salinisation,etc.

Wastelands:Wastelands are those lands which due to their misuse do not fulfil their lifesustaining potential.

Wasteland reclamation: It is a process by which wasteland can be reclaimed for productivepurposes.

Water logging: It is the formation of a continuous column of surface water with groundwater due to over-irrigation of crop fields.

Salinisation: It is the accumulation of various salts in soil profile which increases soil pHand inhibits plant growth. It is caused due to

over-irrigation of crop fields.

Desertification: It is a process in which the productive potential of land in arid and semi-aridareas of the world drops by 10% or more. It is

characterized by loss of vegetation cover,depletion of ground water, salinisation and severe erosion.

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Topic: Forest resources

Objectives: To let the student know about

1. Availability of forest resources

2. Uses of forest resources

3. Over-exploitation of forest resources

4. Consequences of over-exploitation of forest resources

Forest Resources

Forests are renewable resource and are considered as ‘green gold’ of country due to their

immense socio-economic and environmental services. About 33% of the world’s land area is

covered with various types of forests. Former USSR accounts for about a 5th of world’s forests,

Brazil for about a 7th and Canada and USA each for 6-7%. However, almost everywhere the

cover of natural forests has declined. The greatest losses have occurred in tropical Asia where

one third of the forest resources have been destroyed.

Uses of Forests

Forests are of immense value to human beings. Forests are very useful for industry and help in

rural economic growth. Forests have both commercial as well as environmental uses:

Commercial uses:

Forests provide a large number of commercial goods which include timber, firewood, pulpwood,

food items, spices, tannin, dyes, gum, resin, non-edible oils, rubber, fibres, lac, bamboo, canes,

fodder, medicines, drugs and many more items.

Ecological uses:

Ecological services provided by forests are:

• They produce oxygen which is vital for life on earth

• They reduce global warming by absorbing CO2 as raw material for photosynthesis

• Forests are homes of millions of plants and animals species

• Forests regulate water cycle

• Forests bind soil particles in their roots and prevent soil erosion

• Forests absorb many toxic gases and noise and thus help in preventing air and noise

pollution

Over Exploitation of Forests

Forests possess huge potential for human use and are exploited since early times. To meet

growing human demands forests are exploited in many ways including:

• Wood cutting for raw materials like timber, pulpwood, firewood etc.

• Deforestation for road construction

• Clearing of forests for expansion of agriculture fields to meet the food demands

• Clearing of forests for large scale mining

• Destruction of forests for construction of dams to generate hydro-electricity

• Degradation of forests due to over grazing

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Consequences of over-exploitation of forests

Over-exploitation of forests has far reaching consequences like:

• It threatens the existence of many wildlife species due to destruction of their natural

habitats

• Water cycle gets disturbed which affects rainfall pattern

• Soil erosion and loss of soil fertility increases

• In hilly areas it often leads to landslides

• Due to loss of forests more CO2 is added to atmosphere and greenhouse effect is

enhanced

• There are increased chances of floods and droughts

• Scarcity of timber, firewood etc.

What we learnt

Forest Resources: Forests are renewable resource and are considered as ‘green gold’ of country due to

their immense socio-economic and environmental services. About 33% of the world’s land area is

covered with various types of forests.

Over-exploitation of forest resources: It refers to destruction of forest resources to meet growing

human need and greed.

Topic: Water resources

Objectives: To let the student know about

1. Water resources and their types

2. Uses of water resources

3. Over-exploitation of water resources

4. Consequences of over-exploitation of water resources

Water Resources

Water is an essential natural resource on this earth on which all life depends. About 71% of the

earth’s surface is covered by water. Water is a very precious resource because out of total water

reserves of the world, about 97% is salty (marine) water and only 3% is fresh water. Even this

small fraction of water is not available to us as most of it is locked up in polar ice caps and less

than 1% is available to us in the form of ground water and surface water.

Types of water resources

There are two types of water resources – surface water and ground water.

1. Surface water: Surface water is further divided into fresh water and marine water. Fresh

water if found in the form of lakes, ponds, rivers, streams, and springs. Marine water

which accounts for about 97% of total water resources is salty and is not fit for direct

human consumption.

2. Ground water:Ground water constitutes about 9.86% of total fresh water resources.

Ground water is a major source for domestic consumption and agricultural uses.

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Uses of water

Water is of multiple uses for all living organisms. Water is absolutely essential for all forms of

life. Human beings depend on water for almost every developmental activity. Major uses of

water include drinking, cooking, irrigation, transportation, washing, bathing , construction, waste

disposal and as coolant for thermal power plants.

Over-exploitation of water

With increasing human population and rapid development, the usage of water has increased

manifolds. Also various water sources have got polluted due to anthropogenic activities. Rivers

and streams have long been used for discharging and disposal wastes causing pollution in these

water bodies. Overuse of ground water has resulted in rapid depletion of groundwater in various

regions leading to lowering of water table and drying of wells. Pollution of groundwater has also

made it unfit for consumption in many areas.

Consequences of over-exploitation of water resources

Discharge of wastes has resulted in pollution of surface water sources. Overuse of ground water

has also resulted in depletion of ground water in many regions. Consequently there has been

shortage of drinking water supply in many parts of the world. According to United Nations

estimates, more than 1 billion people do not even have access to safe drinking water and 2.4

billion do not have adequate sanitation facilities. It is estimated that by 2024, two-thirds of the

world population would by suffering from acute water shortage.

Sub-Topic: Rain-water harvesting

Objectives: To let the student know about

1. What is rain-water harvesting

2. Significance of rain-water harvesting

3. Techniques of rain-water harvesting

Rain-water Harvesting - definition

Rain water harvesting is a technique of increasing the recharge of ground water by capturing and

storing of rain water by constructing special water harvesting structures.

Significance of rainwater harvesting

Rainwater harvesting has great significance as it reduces surface run off loss and avoid flooding.

It meets increasing demands of water, supplement ground water and raises water table. It also

improves soil moisture and decreases soil erosion.

Methods/Techniques of Rain Water Harvesting

In ancient times rain water was collected in talabs, baawaris, hauz, etc. to be used in dry periods.

Traditionally rain water from roof tops is collected in water storage tanks from where it is

diverted to wells. Now-a-days rain water from large catchment areas is collected in check dams.

It is also collected by constructing ground water dams for storing water underground. In roof-top

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rainwater harvesting, the rainwater from the top of the roofs is diverted to some surface tank or

pit which can be later used for several purposes. It can also be used to recharge underground

aquifers. Watershed management is another effective method of rain water harvesting.

Sub-Topic: Watershed management

Objectives: To let the student know about

1. What is watershed

2. Significance of watersheds

3. Watershed management - methods

Watershed

The watershed is defined as the land area from which water drains under gravity to a common

drainage channel. The watershed can range from a few square kilometres to a few thousand

square kilometres in size.

Significance of watersheds

Watersheds affect us directly as they supply water for irrigation, hydro-power generation,

transportation, vegetation growth, reducing floods and droughts. However, the watersheds are

very often found to be degraded due to overgrazing, deforestation, mining, construction

activities, shifting cultivation, soil erosion, etc. so the management of watersheds becomes

extremely necessary.

Watershed management

Watershed management may be defined as the rational utilization of land and water resources of

optimum production causing minimum damage to the natural resources. Various methods of

watershed management include:

1. Water harvesting: it is done by proper storage of water with provision for use in dry

season.

2. Afforestation and agroforestry: it is promoted to prevent run off loss and soil erosion

and increase soil moisture. In high rainfall areas woody trees are grown in between crops

to substantially reduce the runoff and loss of fertile soil.

3. Mechanical measures: several mechanical measures like terracing, bench terracing, no-

till farming, contour cropping, strip cropping, check dams, retaining walls, etc. are

used/constructed to minimise runoff and soil erosion particularly on the slopes of the

watersheds.

4. Mining and quarrying: it should be done by scientific methods in watershed areas.

5. Public participation: people’s involvement including the farmers and tribals is the key

to success of any watershed management programmes. People’s involvement in

watershed management should be ensured through their proper education and awareness

and giving certain incentives.

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What we learnt

Water Resources: Water is an essential natural resource on this earth on which all life depends. About

71% of the earth’s surface is covered by water of which about 97% is salty (marine) water and only 3%

is fresh water.

Over-exploitation of water resources: It refers to misuse and overuse of water resources by polluting

surface water and depletion of ground water.

Rain water harvesting: A technique of increasing the recharge of ground water by capturing and storing

of rain water.

Watershed management: It refers to rational utilization of land and water resources of optimum

production causing minimum damage to the natural resources.

Topic: Food resources and world food problems

Objectives: To let the student know about

1. What are food resources

2. Staple food

3. World food problems

Food Resources

Food is an organic substance, which is necessary for growth and development of all living

organisms. There are thousands of edible plants and animals over the world however, the main

food resources include wheat, rice, maize, potato, barley, oats, pulses, millet cassava some

common fruits and vegetables, milk meat, fish and seafood.

Staple food

Among all food resources cereals like rice, wheat and maize are the major grains which

constitute half of all the agricultural crops. About 4 billion people in the developing countries

have wheat and rice as their staple food. Meat and milk are mainly consumed by more developed

nations. Fish and seafood constitute about 70 million metric tons of high quality protein to the

world’s diet.

World Food Problems

During the last 50 years world grain production has increase almost three times, but rapid

increase in population growth has outstripped food production. Due to huge population growth in

less developed countries, increased food has not benefited the common man. Every year 40

million people, 50% of which are young children between 1 to 5 years, die of undernourishment

and malnutrition. These figures emphasize the need to increase our food production, equitably

distribute it and also to control population growth. There are about 410 million undernourished

people on the earth. Some ill-effect of undernourishment and malnutrition include

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• High child mortality

• Higher maternal mortality

• Impaired brain growth

• Poor school performance

India is the third largest producer of staple crops, but an estimated 300 million Indians are still

undernourished. It is because India constitutes 17% of world’s population but has only 2.4% of

world’s geographical area. Therefore, India’s food problems are directly related to population.

Sub-Topic: Sustainable Agriculture

Objectives: To let the student know about

1. What is agriculture

2. Concept of sustainable agriculture

3. Steps to sustainable agriculture

Agriculture

Traditional agriculture is more near to natural conditions and usually results in low production. It

is still practiced in about half of the global population. But there are some impacts associated

with this type of agriculture like deforestation, soil erosion and depletion of nutrients. Modern

agriculture on the other hand, involves use of hybrid seeds, high-tech equipments, fertilizers,

pesticides and irrigation water. This has resulted into fertilizers related problems, pesticides

related problems, water logging, salinisation and land degradation. All these resulted to

unsustainability to present day agriculture.

Concept of sustainable agriculture

Sustainable agriculture is the successful management of resources for agricultureto satisfy the

changing human needs along with maintenance and enhancement of the quality of environment

and conservation of natural resources.

Steps for sustainable agriculture:

I. Efficient management of soil and water

Soil quality and fertility determine plant growth, so a number of measures should be taken

to check its quality and to improve it e.g.

a. Overgrazing should be avoided

b. Soil erosion removes nutrient rich top-soil as such various causes of soil erosion should

be minimised

c. Various causes of soil salinisation should be checked

d. Advantageous irrigation systems like drip irrigation, water sprinkling etc. should be

adopted

e. Multi-cropping should be adopted in which crop raising is combined with keeping of

livestock to get every type of food supply

f. Mixed cropping or multiple cropping should be adopted to restore soil fertility

g. Crop rotation which increases the soil fertility and crop production should be adopted

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II. Use of organic manures, compost and fertilizers

a. Organic manures like farmyard manure, compost, green manure and vermicompost

should be used. These improve physical and nutritive status of the soil

b. Chemical fertilizers should be judiciously used to meet the mineral deficiency of the soil

III. Use of biofertilizers

These include symbiotic use of micro-organisms which increase the soil fertility

IV. Biological control of pests

Biological control involves the use of natural enemies of the pests to control their population

and thereby crop damage.

What we learnt

Food resources: Food resources refer to edible plants and animals which we consume for

growth. Main food resources include wheat, rice, maize, potato, barley, oats, pulses, millet

cassava some common fruits and vegetables, milk meat, fish and seafood.

Food Problems: It refers to deficiency of staple food resulting in undernourishment and

malnutrition of people.

Sustainable agriculture: It refers to the successful, sustainable and ecofriendly management of

resources for agriculture.

Topic: Energy Resources and growing energy needs

Objectives: To let the student know about

1. Energy resources and their types

2. Growing energy needs

3. Watershed management - methods

2.6 Energy Resources

Energy is defined as the ability to do work. Per capita energy consumption of a nation is usually

considered as an index of its development. This is because almost all developmental activities

are directly or indirectly dependent upon energy.

A resource of energy is one that can provide adequate amount of energy in a usable form over a

long period of time. The resources of energy are of two types:

1. Renewable resources: which are being used by man, generated continuously by nature

and are inexhaustible e.g. solar energy, wind energy, tidal energy, hydropower, biomass

energy, bio-fuels, geothermal energy and hydrogen. They are also called as non-

conventional sources of energy and can be used again and again in endless manner.

2. Non-renewable resources: they are not renewable for use and are not replenished by

nature if exhausted e.g. fossil fuels like coal, petroleum, natural gas and nuclear fuels like

uranium and thorium.

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Growing energy needs

Prior to industrial revolution, the common source of energy were human/animal muscle power,

wind energy fire wood and vegetable oils. Now there is extensive use of fossil fuels as source of

energy as almost all developmental activities depend largely on energy. Agriculture, industry,

mining, transportation, lighting, cooling and heating all need energy. The fossil fuels like coal,

oil and natural gas are presently supplying 95% of world’s commercial energy. However, these

sources of energy are going to end in coming years. With the demands of growing population

and luxurious life styles, the world is facing further energy deficit. Countries like USA,

Switzerland, Norway, with high GNP (Gross National Product) show high energy use as

compared with countries like India and China.

In highly developed countries like USA per capita per day consumption of energy is around

2,50,000Kcals. In developing countries like India a man uses about 10,000 Kcals energy on an

average. A person in a rich country consumes almost as much energy in a single day as one

person does in a whole year in a poor country. This clearly shows that our life style and standard

of living are closely related to energy needs.

Sub-Topic: Alternate sources of energy

Objectives: To let the student know about

1. The alternate sources of energy

2. Advantages and disadvantages of these resources

Alternate or Renewable Sources of Energy The demand of energy supply due to population growth, development and changing life style has

increased manifold. Further the reduced availability of fossil fuels and the limited capacity of the

world to cope with the overwhelming pollution caused by fossil fuels are the reasons that have

forced the world to seek for alternate sources of energy.In near future, it is expected that fossil

fuel based energy will be replaced by sustainable energy system based on renewable clean and

non polluting energy resources, some of the alternate or non conventional sources of energy are:

1. Solar energy

2. Wind energy

3. Geothermal energy

4. Tidal energy

5. Biomass

Solar Energy

Sun is the ultimate source of energy and solar energy has the maximum potential of all the

sources of renewable energy. The Solar energy received by earth atmosphere is 1.5 1018

kwh/year. The solar energy received near earth’s space is approximately 1.4 kj/second/m2 known

as solar constant.

Traditionally solar energy has been used for drying of clothes, cereals, eatables, and warmth.

Now solar energy is harnessed for various purposes like solar cooking, solar cells, solar water

heaters, solar power, solar furnace, etc.

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Advantages of Using Solar Energy

1. Solar gadgets do not create pollution and hence are eco friendly

2. Maintenance cost is negligible

3. Cheap initial cost

4. Noiseless working.

5. The food cooked in solar cookers is more nutritious due to slow and inform heating.

Disadvantages / Limitations of solar energy

1. Solar gadgets fail to work in nights during cloudy day

2. Solar gadgets do not work in rainy days

3. Solar cooking takes more time, is cumbersome as the face of reflector has to change

according to the position of sun

Wind Energy

Wind energy has tremendous potential to 25x 103 MW. Wind resources are mainly near the sea

coasts. The wind energy is harnessed by making use of wind mills. The minimum wind speed

required for satisfactory working of wind turbines is 15km/hr and in India, winds show relatively

low speed of 5-15 km/hr and hence exploitation of wind energy is an expensive project.The

largest wind farm of our country is near Kanyakumari in Tamil Nadu.

Advantages of Wind Energy

1. Abundant availability

2. It is non-polluting, hence eco friendly

3. Suitable for power generation in coastal and hilly areas

4. Can be used in remote places for power production

Disadvantages / Limitations

1. Highly unreliable and discontinuous as wind does not blow regularly and uniformly

2. Responsible for causing noise pollution

3. Due to its non uniformity the power generated is also not continuous

4. Mechanical energy of windmills has to be stored by batteries due to fluctuating nature of

winds.

Tidal Energy

Tides are formed by the gravitational effect of the sun and moon on earth. This gravitational

force causes rise and fall of water level of sea in sync with the rising and setting of moon. This

periodic rise and fall of seawater is called tide and can be used to produce electricity.

Tidal energy can be harnessed by constructing a tidal barrage. During high tide, sea water flows

into the reservoir of barrage and turns turbine, which in turn produces electricity by rotating

generators. During low tide, when sea level is low, the sea water stored into the reservoir flows

out into sea and turns the turbine.

In India, tidal power has great potential in areas like Gulf of Kuchh, Gulf of Cambay and Sunder

Bans.

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Geothermal Energy

The energy available from natural, underground reservoirs of steam and hot water is called

geothermal power. There is an increase in temperature of the earth with increasing depth below

the surface. All the heat stored in the earth’s crust as thermal energy constitutes an inexhaustible

source of energy termed as geothermal energy.

Hot springs and volcanoes are the sources of geothermal energy. Hot water or underground

steam is used to operate turbines to generate electricity. Geothermal energy sources are being

exploited for sectors like space heating, poultry farming, chemical industries, mushroom

cultivation, etc.

Advantages of Geothermal Energy

1. It is an inexhaustible source of energy.

2. Naturally occurring so free of cost and no fuel required.

3. Can be used to generate power for long periods of time thus show stability.

4. It causes negligible pollution.

Disadvantages / Limitations

1. Not absolutely pollution free, many gases like H, S, CO2, NH3 are produced.

2. Drilling operation is noisy.

3. Extensive land area is used.

Biomass

Biomass is the organic matter produced by plants or animals which may include wood, crop

residues, cattle dung, manure, agricultural waste, etc. It is basically indirect form of solar energy

which is converted to chemical energy by plants. Energy plantation of some fast growing trees

and non-woody grasses to produce energy either by burning directly or converted into fuels by

fermentation. Certain latex containing plants are also cultivated to produce gasoline. Such plants

are known as petro-crops. Biomass can also be fermented to alcohols like ethanol and methanol

which can be used as fuels.

What we learnt

Energy resources: The resources that can provide adequate amount of energy in a usable form over a

long period of time.

Renewable resources: Energy resources being used by man generated continuously by nature and are

inexhaustible.

Non-renewable resources: Energy resources that are not renewable after use and are not replenished

by nature if exhausted.

Growing energy needs: It refers to growing demands of energy by growing population to meet

luxurious life style requirements.

Alternate sources of energy: Sustainable energy system based on renewable clean and non polluting

energy resources.

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UNIT 4: BIODIVERSITY AND ITS CONSERVATION

4.1 Introduction/meaning of biodiversity:

Biological diversity or Biodiversity in short is the sum of all the different species of

microorganisms, fungi, plants and animals living on earth and the variety of habitats in which

they live. They hold an immense value for man and are central to the survival of human

civilizations. The full range and extent of biodiversity is still not known, leave alone their

greatest values and benefits.

The term biodiversity has been defined differently. The Global convention on biodiversity

(CBD) has defined it as “the variability among living organisms from all sources including

terrestrial, aquatic (fresh, estuarine and marine) and the ecological complexes of which

they are a part. This includes diversity within species, between species and of ecosystems.”

Levels of Biodiversity:

Generally three hierarchical levels of biodiversity are recognized namely genetic diversity,

species diversity and ecosystem diversity.

Genetic Diversity:

Genetic diversity occurs between the members of the same species. Within any given species

there can be several varieties, strains or races which slightly differ from each other in one or

more characteristics such as size, shape, resistance against diseases, pests, insects etc and

resilience to survival under adverse environmental conditions. Such variability in the genetic

makeup among individuals within a single species is referred to as genetic diversity.

Species with more number of races, varieties and strains are considered to be rich and more

diverse in its genetic organization. Genetic diversity is needed by any species to maintain its

reproductive vitality, resistance to disease and the ability to adapt to changing conditions.

Species diversity:

Species diversity represents the variety of species in different habitats on earth or in other words

we can say that species diversity refers to the total number of species i.e. species richness of our

earth. Species diversity can be measured on the basis of number of species in a region.

Currently about 1.9 million species are known but this is thought to be a significant

underestimate of the total member of species. It is estimated that the total number of species

could be 5-30 million on our earth and one more estimate by UNEP (1993-94), the total number

of species that might exist on earth range between 9-52 million.

Ecosystem Diversity:

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Ecosystem diversity and ecological diversity is the variety of biotic and abiotic components that

interact with one another and it represents the collective response of a community of species to

different environmental conditions.

An ecosystem develops its own characteristic community of living organisms based upon the

availability of abiotic resources and conditions of the environment, so that is because different

types of ecosystems represent they unique diversity each with a characteristic biotic community.

Values of Biodiversity

Biodiversity not only maintains the equilibrium of ecosystems, it is also an inexhaustible source

of potential new drugs. Biodiversity helps to sustain a healthy food chain and promotes water,

soil and air quality. Each species plays its own role i.e. has its own importance. Biodiversity is

vital to our biosphere’s health, stability and its proper functioning.

The global concern for the need to preserve biological diversity stems from its enormous

significance and inestimable value to mankind. Our tendency to evaluate everything in terms of

direct economic benefits or costs has resulted in the severe undervaluing of biodiversity in the

past. Even now it is not possible to convert the potential benefits of biodiversity into monetary

values for assessment.

However we can classify the values of biodiversity into direct and indirect values as shown in the

below figure.

Direct Values

Also known as use values and commodity values and are assigned to the products harvested by

people. The direct values include food resources like grains, vegetables, fruits which are obtained

from plant resources and meat, fish, egg, milk and milk products from animal resources. These

also include other values like medicine, fuel, timber, fiber, wool, wax, resin, and rubber, silk and

decorative items.

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The direct values are of two types

• Consumptive use value

• Productive use value.

Consumptive use value: These are the direct values where the biodiversity products can be

harvested and consumed directly. Example food, fuel and drugs. These goods are consumed

locally and do not figure in national and international market.

(a) Food

• Plants: The most fundamental value of biological resources particularly plants is

providing food. Basically three crops viz wheat, maize, and rice constitute more than

two third of the food requirement all over the world.

• Animals:

• Fish: Through the development of aquaculture techniques fish and fish products have

become the largest source of protein in the world.

(b) Fuel: Since ages forests have provided wood which is used as a fuel. Moreover fossil

fuels like coal, petroleum, natural gas are also products of biodiversity which are directly

consumed by humans. All through fossil fuels have productive use values.

(c) Drugs and medicines: The traditional medical practices like ayurveda utilize plants or

their extracts directly. In allopathy, the pharmaceutical industry is much more dependent

on nature products. Many drugs though having productive use values are derived from

plants like

(i) Quinine: - The famous anti-malarial drug is obtained from cinchona tree.

(ii) Penicillin: - A famous antibiotic derived from pencillium, a fungus

• Digitalis and Digitoxin from foxgloves have saved millions of heart patients.

• Recently vinblastin and vincristine- two anti cancer drugs have been obtained from Rosy

Periwinkle plant which has anti cancer alkaloids.

Productive use values: These are the direct use values where the product is commercially sold

in national and international markets. Many industries are dependent upon these values.

Examples textile, leather, silk, pump, paper and pulp industry etc. although there is an

international ban on trade of products from endangered species like tusks of elephants, wool

from sheep, fur of many animals etc. these are traded in market and fetch a booming business.

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Indirect values:

Biodiversity provides indirect benefits to human beings which support the existence of biological

life and other benefits which are difficult to quantify. There include social and culture values,

ethical values, aesthetic values, option values and environment service values.

Social and cultural values: Many plants and animals are considered holy and sacred

inIndia and are worshiped like tulsi, peepal, cow, snake etc. In Indian society great cultural value

is given to forest and as such tiger, peacock and lotus are named as the national animal, bird and

flower respectively.

Ethical: These values are related to conservation of biodiversity where ethical issue of "all

life forms must be preserved" is laid down. There is an existence value which is attached to each

species because biodiversity is valuable for the survival of human race. More over all species

have a moral right to exist independent of our need for them.

Aesthetic value: There is a great aesthetic value which is attached to biodiversity. Natural

landscape at undisturbed places are a delight to watch and also provide opportunities for

recreational activities like bird watching, photography etc. It promotes ecotourism which further

generates revenue by designing of Zoological parks, Botanical gardens, National parks, Wildlife

sanctuaries etc.

Optional value: These values include the unexplored or unknown potentials of

biodiversity.

Environment service value: - The most important benefits of biodiversity is maintenance

of environmental services which include

• Carbon dioxide fixation through photosynthesis.

• Maintaining of essential nutrients by carbon, Oxygen, Nitrogen, Sulphur, and

Phosphorous Cycles.

• Maintaining water cycle and recharging of ground water.

• Soil formation and protection from erosion.

• Regulating climate by recycling moisture into atmosphere.

• Detoxification and decomposition of waste.

4.2 Threats to Biodiversity

Biodiversity loss is one of the important and serious environmental threats that humanity faces.

In earths 5.5 billion year history there have been five major “mass extinctions” recorded in the

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fossil record, the most recent of which, 65 million years ago, killed the last of the true dinosaurs.

Scholars believe that we are currently experiencing extinction rates rivaling or exceeding the

rates of the prehistoric mass extinctions.

Biodiversity losses can be attributed to the resource demands of our rapidly growing human

population. In modern times the human population has increased from 1 billion in 1900 to over 7

billion today. Like other living beings, we use natural resources to survive but we are far more

resourceful and destructive to other life forms than any other species previously known. As the

world’s human population increases all the organisms on earth (including ourselves) must share

the same limited resources (food, water, space). Yet there is less and less natural habitat

remaining as land is developed for human habitation and activities.

Here are some of the major reasons which caused loss of biodiversity and are threats to

biodiversity.

1. Habitat loss and fragmentation: is considered by conservation biologists to be the primary

cause of biodiversity loss. Clearance of native vegetation for agriculture, housing, timber and

industry as well as draining wetlands and flooding valleys to form reservoirs, destroys these

habitats and all the organisms in them. In addition, this destruction can cause remaining habitats

fragmented and so too small for some organisms to persist or fragments may be too far apart for

other organisms to move between. Sometimes habitat fragmentation occurs due to construction

of roads, towers and canals. Habitat fragmentation divides populations into isolated groups that

not only limit the potential of species for dispersal and colonization but also reduces the foraging

ability of animals. These isolated, small, scattered populations are increasingly vulnerable to

inbreeding depression, high infant mortality and susceptible to environmental hardships and

consequently in the end, possible extinction.

2. Invasive alien species: They are the second greatest threat to biodiversity worldwide,

whether introduced for any purpose or accidently. Non- native species can cause severe problems

in the ecosystems they invade, from affecting individuals to causing huge changes in ecosystem

functioning and the extinction of many species. Virtually all ecosystems worldwide have

suffered invasion by the main taxonomic groups. This problem possibly gets worsened by

climate change and an increase in global trade and tourism. As well as the risks to human health

alien species inflict massive economic costs to agriculture, forestry, fisheries and other human

activities.

For example introduction of Nile Perch from North in Lake Victoria, Africa’s largest lake

has driven almost half of the 400 original fish species of the lake to near extinction.

3. Pollution: Pollution is currently poisoning all forms of life, both on land and in water and

contributing to climate change. Any chemical in the wrong place or in the wrong concentration

can be considered a pollutant. Transport, industry, construction, extraction, power generation and

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agro forestry all contribute pollutants to the air, land and water. These chemicals can directly

affect biodiversity or lead to chemical imbalances in the environment that ultimately kill

individuals, species and habitats.

4. Climate change: Climate change brought about by emissions of greenhouse gases when

fossil fuels are burnt is making life uncomfortably hot for some species and uncomfortably cold

for others. This can lead to change in the abundance and distribution of individual species around

the globe and will affect the crops we grow, cause a rise in sea levels and problems to many

coastal ecosystems. In addition the climate is becoming more unpredictable and extreme

devastating events are becoming more frequent.

5. Over exploitation and poaching: Over exploitation by humans causes massive destruction to

natural ecosystems. Exploitation of biodiversity occurs for good (e.g. fish), construction (e.g.

trees), industrial products (e.g. animals, blubber, skins), the pet trade (e.g. reptiles, fish, orchids,

fashion e.g. (fur, ivory) and traditional medicines (e.g. rhino horn). Selective removal of an

individual species can unbalance ecosystems and all other organisms within them. In addition the

physical removal of one species often harms other (e.g. fishing by catches). Poaching which

means illegal /unlawful trade of wild plants and animals through hunting, harvesting, fishing or

trapping is also causing loss of biodiversity at a very fast rate. The lure of spectacular profits

drives the illegal trade in endangered species and their products. In spite of laws prohibiting the

trade, consumers all over the world are willing to pay 95, 000 dollars for a Bengal tiger coat.

Similarly a coat made of South American Ocelet costs 40000 dollars. Poaching contributes to

loss of biodiversity. Poaching is of 3 types listed below:

i.Subsistence poaching: This refers to killing animals for survival.

ii.Commercial poaching: This refers to hunting animals in order to sell their products.

iii.Recreational or Sport or Game poaching: This refers to the hunting of wild animals for

recreational purposes or for fun.

Man- wildlife conflict

Man- wildlife conflict refers to the interaction between wild animals and people and the resultant

negative impact on people or their resources or wild animals or their habitat. It occurs when

growing human populations overlap with established wildlife territory creating reduction of

resources or life to some people and or wild animals.

As human population extends to wild animal habitats natural wildlife territory is displaced

the population density of wildlife and humans overlaps increasing their interactions thus

resulting in increased physical conflict. Byproducts of human existence offer unnatural

opportunity for wildlife in the form of food and shelter, resulting in increased interference and

potentially destructive threat for both man and animals.

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Various forms of man wildlife conflict occur with various negative results some of these are

• Animals deaths

• Crop damage

• Damage to property

• Destruction of habitat

• Injuries to people

• Livestock depredation

• Loss of human life such as by

Tiger Attacks: Tiger attacks are an extreme form of man wildlife conflict which occurs for

various resources and have claimed more human lives than attacks by any of the other big cats.

The most comprehensive study of deaths due to Tiger attacks estimates that at least 373,000

people died due to Tiger attacks between 1800 and 2009, the majority of these attacks occurring

in South and Southeast Asia. In Southeast Asia attacks gradually declined after peaking in the

nineteenth century, but attacks in South Asia have remained high particularly in the Sunder bans.

If a human comes too close to and surprises a sleeping or a feeding tiger (particularly if it is a

Tigress with cubs), Tiger may attack humans in a case of a “mistaken identity” (for example if a

human is crouching while collecting firewood or cutting grass) and sometimes when a tourist

gets too close.

These attacks actually happen due to shrinkage and loss of original habitat of wild animals. As

a result these wild animals find it difficult to thrive there because of shortage of food and other

necessary requirements and come out into direct conflict with human inhabitated areas. They

damage crops in agricultural fields and thereby resulting in economical loss to farmers. In

revenge farmers kill these wild animals and thereby causing loss of biodiversity.

Potential solutions to these conflicts include habitat conservation and preservation, electric

fencing, land use planning, community based natural resources management (CBNRM),

compensation, payment for environmental services, ecotourism, wildlife friendly products or

other field solutions.

In efforts reduce man wildlife conflict world wide fund for nature (WWF) has partnered with a

number of organizations to provide solutions around the globe. Their solutions are tailored to the

community and species involved. For example in Mozambique communities started to grow

more chili paper plants after making the discovery that elephants dislike and avoid plants

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containing Capsaicin. This creative and effective method prevents elephants from trampling

community formers fields as well as protects the species.

4.3 Threatened Species

The term threatened species is used in the conservation context for species which are in one of

the below three categories: endangered, vulnerable and rare. Some species are marked as

threatened where it is known that they are endangered, vulnerable or rare but there is not enough

information to say which of the three categories is appropriate.

The international union for conservation of nature and natural resources (IUCN) develops

different categories of species based on certain criteria.

• The present and past distribution.

• Decline in the number of population in Course of time.

• Abundance and quality of natural habitat.

• Biological and potential value of species.

The different categories are as under:

• Endangered species: These are species which are in danger of extinction. The survival

of such species is difficult if the negative factors that have led to a decline in their

population continue to operate. The examples of such species are Black Buck, crocodile,

Indian wild Ass, Indian Rhino, Nepenthes khasiana, Kashmiri stag (Hangul) etc.

• Vulnerable Species: These are species whose population has declined to levels from

where it is likely to move into the endangered category in the near future if the negative

factors continue to operate. The examples of such species are Blue sheep, Asiatic

elephant etc.

• Rare species: Species with small world populations that are not at present endangered or

vulnerable but are at risk. These species are usually localized within restricted

geographical areas or habitats or are highly scattered over more extensive range e.g.

Farestia marcantha, whooping crane etc.

• Extinct species: These are species which are not found after searches of known or likely

areas where they may occur. A species may be extinct from a local area, region, country,

continent or the entire earth. Examples of such species are the Asiatic cheetah, Pink head

duck, Dodo Bird.

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Endemic species and Exotic species:

Species which is only found in a given region or location and nowhere else in the world is known

as an endemic species. An endemic species is one whose habitat is restricted to a particular area

or locality. The term could refer to an animal, a plant, a fungus or even a microorganism.

India is quite rich in biodiversity endemism. About 33% of the country’s flora are endemic and

are concentrated mainly in the north east, Western Ghats, North West Himalaya and the

Andaman and Nicobar islands. Similarly 62% of the known amphibian species and 50% of the

lizards of the country are endemic with the majority occurring in the western- Ghats also a

hotspot of biodiversity.

Exotic Species

Exotic species are those organisms introduced into habitats where they are not native. Invasive

exotic species are organisms not native to a region and whose introduction causes economic or

environmental harm or harm to human health. In their natural habitats these organisms develop

stable populations and complex relationships with other species. When removed from the

predators, parasites, diseases and competitors that have kept their numbers in check, species

introduced into new habitats often over run their new home and crowd out native species once

established, exotic species can rarely be eliminated.

4.4 Conservation of Biodiversity:

Conservation may be defined as the management and sustainable use of the natural environment

and natural resources for ethical reasons and the benefits of humanity. (Fiedler and Jain 1992).

The IUCN defines conservation as the management of human use of the biosphere in order for it

to yield the greatest sustainable benefit to current generation while maintaining its potential to

meet the needs and aspirations of future

In –Situ conservation

In- situ conservation or on-site conservation means conservation of species in its natural habitat

i.e. in places where the species normally occurs. For the present discussions, following in-situ

conservation means have been taken into consideration.

National parks:

National park was first introduced in 1969 by IUCN as a means of a protected area. A national

park is an area dedicated to conserve the scenery (or environment) and natural objects and the

wildlife therein. In national parks private rights are non- existent and all forestry operations and

other usages such as grazing of domestic animals are prohibited. However the general public

may enter it for the purpose of observation and study, certain parts of the park are developed for

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tourism in such a way that enjoyment will not disturb or scare the animals. Also a national park

is hitched to habitat for a particular wild animal species like Lion, Tiger, Rhinoceros, and Hangul

etc.

Wildlife Sanctuaries:

A wildlife sanctuary, similar to national park, is dedicated to protect the wildlife but it considers

the conservation of species as Great Indian Bustard, pitcher plant etc and also the boundaries of

it is not limited by state legislation. Further in a sanctuary killing, hunting or capturing of any

species of birds and mammals is prohibited except and by or under the control highest authority

in the department responsible for management of the sanctuary. Private ownership may be

allowed to continue in a sanctuary and forestry and other usages are permitted to a extent that

they do not adversely affect wildlife.

Biosphere Reserves:

Biosphere reserves aim at conserving the biological diversity and genetic integrity of plants,

animals and microorganisms in their totality as part of the natural ecosystems, so as to ensure

their self perpetuation and unhindered evolution of the living resources. In Biosphere reserves

the whole area (ecosystem) is protected and not any one particular plant or animal species.

Furthermore Biosphere reserves are organized into three zones. At the centre of the reserve is a

core conservation zone, accorded the highest degree of protection from commercial resources

exploitation and other forms of destructive interference. In core zones only non- disruptive

research and monitoring are normally permitted.

A secondary shell around the core is designated as the buffer zone in which limited and regulated

human activities are permitted including ecologically oriented tourism, training, low impact

experimental research and traditional low intensity agriculture and resources gathering activities.

The territory landscape surrounding the buffer zone is the transition zone which as its name

implies serves as a boundary between the biosphere reserve and the surrounding landscape.

Human settlements and more intensive economic activities are permitted in the transition zone

again provided that they are fundamentally consistent with the protection of core.

Q: What is the difference between a sanctuary and a national park?

Hunting without permit is prohibited and grazing or movement of cattle is regulated in sanctuary.

But hunting and grazing are absolutely prohibited in national park which may be established

within or outside a sanctuary i.e. the difference is mostly the interference of human or human

activities in the area. In a sanctuary the human activities are allowed but in a national park the

human interference is totally prohibited.

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Ex- Situ Conservation

Ex – situ conservation or off-site conservation means conservation of endangered plants and

animal species away from their natural habitat under human supervision/ care or in other words

we can say that off-site conservation is conservation in captivity under human care. For the

present discussions, following ex-situ conservation means have been taken into consideration.

(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 plasm is kept under controlled

temperature and humidity for storage; this is an important way of preserving the genetic

resources.

(iii) Tissue culture: 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 is virus and disease free method of multiplication.

(iv) 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.

(v) Zoological Gardens: In zoos wild animals are maintained in captivity and

conservation of wild animals (rare, endangered species). In world there are about 800

zoos. Such zoos have about 3000 species of vertebrates.

4.5 Hotspots of Biodiversity:

The hotspot of biodiversity concept was first of all introduced by a British ecologist Norman

Myers in 1988, wherein he recognized that a modest number of ecosystems accounted for a high

percentage of biodiversity. Conservation international (CI) has identified these biologically rich

areas under the greatest threats of destruction as biodiversity hotspots. These hotspots are

identified on the basis of three criteria:

• the number of species present,

• number of those species found exclusively in an ecosystem and

• The degree of threats they face.

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Thus hotspots of biodiversity are such areas on the surface of earth which have high species

richness as well as high species endemism. Earlier Norman Myers and a team of scientists (2000)

had updated the list of such areas to 25. But currently there are 34 hotspots of biodiversity in the

world. They represent just 2.3% of Earth’s land surface, but they support more than half of the

world’s plant species as endemics. These areas and the species present within them are both

under high levels of threat and of significant global value based on their uniqueness. Therefore,

operations that occur within global biodiversity hotspots should follow rigorous biodiversity

assessments to prevent further biodiversity loss within these areas. This is a global scale

approach based on coarse scale ecoregions that therefore, has limited use for site-scale

assessment and decision making. Biodiversity hotspots will include areas of high biodiversity

importance as well as degraded land and urban areas and therefore more detailed assessments are

needed to locate the actual distribution of biodiversity within these areas.

India's rich biological diversity - its immense range of ecosystems, species and genetic forms is

by virtue of its tropical location, climate and physical features. Almost 60-70% of the total

global Biodiversity could be found in just 17 out of the over 200 countries of the world. Such

large concentrations of biodiversity in small parts of the world give rise to the concept of mega

diversity which was first proposed at the Smithsonian biodiversity conference in 1988. So far

there have been identified 12 such countries which have been tagged as mega diversity countries

or megacentres of biodiversity. The mega diversity countries or centers are Mexico, Columbia,

Brazil, Peru, Ecuador, Zaire, Madagascar, Indonesia, Malaysia, India, China and Australia.

Thus India is one of the 12 mega diversity centers in the world. India just having 2.4% of the

total land area of the world, contributes almost 8.22% of the global known biodiversity.

India has three major hotspots. The rate of deforestation in these areas is very high and

ecosystems have reached at a fragile stage.

The Western Ghats: The Western Ghats are a chain of hills that run along the western edge of

peninsular India. They run parallel to the west coast of India and constitute more than 1600 km

strip of forests in the states of Maharashtra, Goa, Karnataka, Tamil Nadu and Kerala. These

regions have moist deciduous forest and rain forest. The region shows high species diversity as

well as high levels of endemism. There are over 6000 vascular plants belonging to over 2500

genera in this hotspot, of which over 3000 are endemic. Nearly 77% of the amphibians and 62%

of the reptile species found here are found nowhere else. The region also harbors over 450 bird

species, about 140 mammalian species, 260 reptiles and 175 amphibians. Over 60% of the

reptiles and amphibians are completely endemic to the hotspot.

The Eastern Himalayas: The Eastern Himalayas is the region encompassing Bhutan, north-

eastern India, and southern, central, and eastern Nepal. There are 10,000 species of plants in the

Himalayas, of which one-third are endemic and found nowhere else in the world. Few

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threatened endemic bird species such as the Himalayan Quail, Cheer pheasant. Western tragopan

is found here, along with some of Asia’s largest and most endangered birds such as the

Himalayan vulture and White-bellied heron. The Eastern Himalayan hotspot has nearly 163

globally threatened species including the One-horned Rhinoceros, the Wild Asian Water buffalo

and in all 45 mammals, 50 birds, 17 reptiles, 12 amphibians, 3 invertebrate and 36 plant species.

Indo-Burma: The Indo-Burma hotspot comprises the Southeast Asian nations of Vietnam,

Thailand, Cambodia, Laos, Myanmar (formerly, Burma), and portions of eastern India and

southern China. It follows along the coast extending thousands of miles and includes the islands

within the South China Sea, Gulf of Thailand, Andaman Sea, and the Bay of Bengal. Indo-

Burma is made up of widely diverse ecosystems, including mixed wet and dry evergreen forests,

deciduous and mountain forests, lowland floodplains, swamps, and mangroves. Of the 13,500

vascular species found in Indo-Burma, 52 percent are endemic to the region, including a wide

array of orchids and tropical hardwoods. Among vertebrates, the numbers are similar: 54 percent

of amphibian, 39 percent of reptile, and 16 percent of mammal species are endemic to the area.

Twenty percent of the world’s freshwater turtle species and about 10 percent of the world's

freshwater fish species live in Indo-Burma.

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