18CEO305T

ENVIRONMENTAL IMPACT ASSESSMENT

Ecology as a discipline is focused on studying the interactions
between an organism of some kind and its environment.
In ecology, 'niche' refers to the role an organism or species play in
its ecosystem.

The science of ecology has had a gradual development through

history.

The term ecology was first proposed by a German Biologist Ernest

Hackel in 1866. The word is derived from two Greek words „Oikos‟
that means house, a place to live and logos i.e. the study of.
Therefore ecology is a study of organisms at home.
An organisms niches includes everything affected by the organism
denying its lifetime. We study ecology to learn how nature
works.

So ecology is a study to achieve a new goal to help scientists to

develop methods to protect the natural world - physical
environment.

Definition is the simple one most offers given' a study of animal

and plants in their relations to each other and to their
environment.

Animal ecology, however, cannot be adequately understood except

against a considerable background of plant ecology.
 ENVIRONMENT
The term environment describes the sum total of physical and biotic
conditions influencing the responses organisms.

More specifically, the sum of those portions of the hydrosphere,

lithosphere, and atmosphere into which life penetrates is the biosphere.

There are no characteristics of permanent inhabitants of the atmosphere,

although the air is traversed by manly kinds of animals and plant
propagules.
Of the hydrosphere, there are two major bicycles, marine and fresh
water, of the lithosphere there is one land.

Environment can be classified into Three broad types

 a) Biotic (living)

The word biotic refers to having to do with living organisms.

Biotic elements refer to the biological component of the ecosystem,
consisting of population of plants, animals and micro organisms in
complex communities

The biotic factors influencing an organisms, viruses and other

parasytic organisms cause diseases.
There are all parts of an organisms biotic environment.
The biotic component of the ecosystem consists of 3 distinct
groups of organism, the producers, consumers and decomposers.
 The producers are those organisms capable of photosynthesis,
production of organic material solely from solar lift and carbondioxide.

 This organic material serves as a source of both energy and mineral

nutrients.
 Both are required by all living organisms.

Examples include both terrestrial and aquatic plants such as

phytoplankton
The consumers are organisms whose very survival depends on the
organic material manufactured by the producers.

Producers: The role of producers is to prepare food to provide

nutrition to the other organisms present in the ecosystem. There are
two types of producers; photoautotrophs and chemotrophs.

The consumer represent animals of all sizes ranging from large

predators to small parasites, such as mosquitoes and flies.

The nature of the consumers dependence on the producers takes

various forms.

Some consumers (herbivores such as rabbits) are directly dependent

on primary producers of for energy. Others (carnivores such as
tigers)depend indirectly on primary producers.
Photoautotrophs: These are green plants which can trap sun
light to form carbohydrate, simple sugar from carbon di-
oxide and water.

This process is known as photosynthesis and these

organisms are called as photoautotrophs.

Chemoautotrophs: Few bacteria such as sulfur bacteria,

nitrifying bacteria, can be able to utilize free energy
released from the chemical reactions to prepare organic
food with it.

They are called chemoautotrophs and the process is known

as chemosynthesis.
The last group of living organisms is the decomposers

Dead plants and animals form the organic debris in the pond. The
decomposer such as bacteria and fungi decay dead body into the
simple organic and inorganic substances.

These include microorganisms such as fungi, bacteria, yeast etc.

as well as a diversity of worms, insects and many other small
animals.

 They all rely on dead organisms for their existence and survival.

 In their efforts to survive and obtain energy they decompose

materials released by plants and consumers to their original
elements (C,O,H,N,S,P).
b) Abiotic - Abiotic factors* include the flow of energy necessary to
maintain any organism, the physical factor that affect it and the supply
of molecules required for its life functions.
Other physical factors include climate, temperature, preciptation,
including its types (rain, snow, hill) around and seasonable distribution,
types of soil present (sandy or clay, dry or wet, fertile or infertile).
All forms of life require atoms such as carbon, nitrogen and
phosphorous and molecules such as water to construct and maintain
themselves.
The organisms constantly obtain these materials from environmental by
eating food or taking them us through the process of photosynthesis.
In the ecosystem, the abiotic (non-living) components perform 3
important function water and oxygen for organisms.
2nd, they act as a reservoir of the 6 most important elements for
life, carbon(C), hydrogen(H), Oxygen (O), nitrogen (N), Sulphor (S)
and phosphorus (P).
These elements constitute 95% of all living organisms. 3rd, the Earth
contains only a fixed amount of these elements.
Thus continual functioning of the ecosystem requires one thing at
least.
These elements have to be recycled because they are critical to the
welfare of the ecosystem as a whole.
Cultural - The stage of development that human being have attained in
the path towards progress will determine their culture as way of life.
Human interaction with environment also influence the ecosystem.
People of different cultures view their place in society from different
angles. Among the factors that can shape their views are religious
understandings, economic pressures and fundamental knowledge of
nature.
Due to this diversity of background different cultures put different
values on the natural world. But the general attitude has been one of
development rather than preservation.
Technology has been the key to human progress. Technology has also
increased the quantity of environmental degradation.

Human interaction with the environment has increased very fast of late.
For example, the green house effect is thought to result from energy
consumption, agricultural practices and climatic change.

It is now felt that we have entered an era characterized by global change

that arises from the interdependence between human development
and their environment.

So self conscious and intelligent management of the earth is one of the

greatest challenges facing humanity today.

Human also cause extinction link indirect ways. The building of dams
changes the character of rivers, making them less suitable for some
species.
 Ecosystem
An animal can not live in isolation and interact with biotic and
abiotic factors, these relationship constitute the ecological system
or ecosystem.

In other words, ecosystem is defined as structural and functional

unit of the biosphere, comprising living and non-living factors and
their interaction.
 Ecosystem and its Characteristics
The biotic and abiotic elements, as shown in Figure 1.1, are
interrelated and function in an orderly manner as a definite
system.
To fully develop the concept of ecosystem, we will look at
characteristics of ecosystems from three points of view:

Structure of ecosystem that consists of nonliving and living parts.

Nonliving parts include water, air and rocks.
Living community called ecological community is set of interacting
species within ecosystem.
2. Processes such as energy flows through it and chemical
element cycle within it.
3. Process of succession that changes an ecosystem over a time
and can undergo development.
DIFFERENT TYPES OF ECOSYSTEM: Ecosystem is an open
system and material can exchange from one ecosystem to
another ecosystem.

For ex. Frog move from the pond to the land and vice-versa. The
ecosystem can be classified based on size, nature and duration;

Nature : On the basis of nature, it can be natural or artificial.

Natural Ecosystem: This ecosystem forms naturally without
interference of human.

Example include are pond, river, forest, village, hill etc. Artificial
Ecosystem: This ecosystem is developed and maintained by
human.

Example include are flowerbed, backyard, aquarium etc.

Duration: On the basis of duration, ecosystem can be
classified as temporary or permanent.

Temporary ecosystem: it is short lived and man made or

natural. Example include rain fed pond.

Permanent ecosystem: It is long lived and self supported

natural ecosystem for very long period. Example includes
forest, river etc.
 Size: Ecosystem is classified as small or large ecosystem.

Small: it is small and also known as microecosystem. It can

be temporary or permanent.

For ex. Pond, flowerpot etc Large: it is large in size and also
known as macroecosystem.

It is always permanent and mostly natural. For ex. Ocean,

river, forest and desert.
STRUCTURE OF ECOSYSTEM:
Each and every ecosystem has several components to sustain it for
long duration. It needs matter (water, oxygen, mineral, carbon
dioxide), different types of organisms and continuous recycling of
energy (Figure ).

These requirements are met by two important components present

in ecosystem; biotic components and abiotic components.
Element cycles
There are number of chemical elements cycles that exist in
ecosystem some of the cycles like nutrient cycle, water
cycle, carbon cycle, nitrogen and phosphorous cycle
 Nutrient cycling
Nutrients are atoms and molecules that are essential for the growth of
plants and trees.
Examples of nutrients that are important to plants are carbon (C),
nitrogen (N), magnesium (Mg), calcium (Ca), iron (Fe) and
phosphorus (P).
Note that nutrients are not the same as energy, which comes originally
from the sun and is converted, via photosynthesis, into sugars that feed
the plant.
The fundamental difference between energy and nutrient transfer is that
the pattern of nutrient transfer is basically circular or cyclical.
Different nutrients are important to different chemical

processes within and between plant cells.

For example, plants use nitrogen to synthesize proteins, DNA

and many other molecules.

Magnesium is a component of chlorophyll, i.e., the molecule

that helps plants capture solar energy.

Cycling ensures that nutrients do not get stuck somewhere in the
soil.
For instance, when a plant dies, all its nutrients end up in the soil.

Bacteria and fungi break down the plant tissue and free up the
nutrients, which other plants growing in the same soil consume.

Recyclers (mainly fungi and bacteria) are important in

maintaining availability of nutrients in all ecosystems.
Physical processes such as air and water movement influence
the fate of these nutrients to variable extents.

The cycles also differ in scale from local to global, and each is
increasingly subject to human impact – deliberate or accidental.

The major cycles occurring in nature include the following:

Water cycle: This essentially involves physical processes of
precipitation, evaporation and water flow with solar energy as
the driving force. However, organisms and especially plants
modify evaporation and precipitation. The presence of water in
oceans and the atmosphere makes this a global cycle

Carbon cycle: This is also global but organic processes (e.g.,

photosynthesis and respiration) play a more dominant role
than in the water cycle.
Nitrogen cycle: This is perhaps the most complex in that so many
organisms are involved in the transformations. Essentially, the
only way nitrogen finds it way into the food chain is through
nitrogen-fixing bacteria. Note that nitrogen is the limiting nutrient in
many ecosystems.

Phosphorus cycle: This is simpler than the nitrogen cycle and

does not depend on a single class of organisms. Phosphorus is
widely present in the earth's crust, although it may often be
insoluble and unavailable to plants.
FOOD CHAIN, FOOD WEB and TROPIC LEVELS
CHARACTERISTICS OF FOOD CHAIN:
The sequential inter-linking of organisms involving transfer
of food energy from the producers, through a series of
organisms with repeated eating and being eaten is referred
as “food chain”.
The biotic components of the ecosystem are linked to each
other through food chain.

In a typical food chain, producers are at the bottom and their

role is to provide food for rest of the community utilizying
solar energy (Fig)
Other organisms belongs to the consumers and finally
decomposer are present at the bottom to recycle the organic
content.
In this manner, a nutritive interaction relationship exist
between the living organisms of an ecosystem.
It is always straight and always follow progressive straight line.
The flow of energy is also unidirectional, from sun to
producer and then different series of consumers.
In a typical food chain, there are always 4 or 5 trophic level in
the food chain.
The distinct sequential steps in the straight food chains are
referred as different trophic levels.

For ex. Green plants stand at the first trophic level; the
herbivorous are the second trophic level; and flesh eaters
represent the third trophic levels.

The position of plant is at the bottom but the position of other

organism varies to different trophic level in different food chains.

The typical representative food chains are given in the Table 39.1.
TYPES OF FOOD CHAIN:
There are two different types of food chains; grazing food
chain and detritus food chain.
Grazing food chain: In the grazing food chain, solar energy
is entrapped by the plants and then biomass, in tune eaten
by the herbivorous, and these are subsequently been
consumed by a variety of carnivorous.
These are longer food and these food chains end at the
decomposer level. Here are two typical example of this type
of food chain to understand this type of food chain.
(1) Food chain in a pond: In a pond, floated or rooted plants

and algae are responsible for performing

photosynthesis to prepare food for other member of

ecosystem.

(2) They represent producers in the food chain (Figure

39.2). Unicellular algae are consumed by protozoan,

water flies, snail, mosquito larvae and tadpoles. These

small organisms represent primary consumers.

These organisms are eaten by hydra, dragonfly larvae,
giant insects and small fishes. These are secondary
consumers.
Large fishes and frog fed on these organism and represent
tertiary consumers.
Frog and fishes are eaten by snakes, birds and these are
quaternary consumers.
Death of all these organism become the food for bacteria
and fungus to produce simple inorganic materials for reuse
by the producers.
Food chain on land: A typical land food chain is given in
Figure 39.3. In land food chain, grass and tree are the
producers.
Grass is eaten by rabbit and other herbivorous.
They represents the primary consumers. Rabbit is eaten by
cats (secondary consumers), which in-turn eaten by wolves
(tertiary consumers).
Both cat and wolves will be consumed by tigers and other big
carnivorous (quaternary consumers).
Death of all these organism become the food for bacteria and
fungus to produce simple inorganic materials for reuse by
the producers.
Detritus food chain: Unlike grazing food chain, detritus
food chain starts with the dead organic matter either
from fallen leaves or dead animal bodies.

This food chain doesn’t depends on solar energy.

Common example of detritus food chain is marsh land

where mangrove leaves fall into the warm, shallow water
(Figure 39.4).
The detritus eating animals ex. Bacteria, fungi and protozoan
act upon the dead matter of dead leaves to covert them into
simple inorganic substances.

The detritivorous are subsequently eaten by insect larvae,

grass shrimp, copepods, crabs, nematodes, bivalve
mollusks, amphipods, mysids etc.

In the last step, the detritus consumers are finally eaten by

fishes.
Food Web: The different food chains are inter connected at
various trophic level to develop a food web (Figure 39.5).

For example, in grassland ecosystem, grass is consumed by

the rabbit but in their absence, it may be eaten by the
grazing cattle.

Similarly, rat or mouse is eaten by snake but snake can be

eaten by predatory birds. In contrast to food chain, food web
has several distinct characteristic.
(1) Food web are never straight.
(2) Food web is formed due to interlinking of food
chains.
(3) A food web in the ecosystem brings alternate source
of food. The complex food web gives better stability
to the ecosystem.
Most of the animals are polyphagous and they feed on more
than one kind of organism.
If the availability of one particular animal is decreasing in the
ecosystem, they start eating alternate animal.
As a result, it gives chance to other animal to reproduce and
grow in number and in addition, it gives chance to
predator to survive.
Ecological Pyramids: In a food chain, producers and
consumers at different trophic level are connected in
terms of number, biomass and energy.

These properties reduces from producers to consumers

and representing these parameters for food chain gives a
pyramid with a broad base and a tapering apex (Figure
39.6).
Ecological pyramids can be of three types:
(a) Pyramid of Numbers
(b) pyramid of biomass
Example of inverted ecological pyramid is provided by
parasitic food chains (Figure 39.7).

A single mango tree supports large number of birds, which in

turn supports a large number of parasites like lice and bugs.

Hyperparasites, such as bacteria and fungus are the

greatest in the number and occupy the top of the inverts
pyramids.
Flow of energy in food chain: Sun is the ultimate
source of energy on earth and plants utilizes it to
produce food for rest of the member of the ecosystem.
Only the 1% of the total energy fall on green part of
leaves is changed into the potential energy of the
organic substances, the rest of the energy dissipates
as heat.
To explain the flow of energy, lindermann proposed the
law of ten per cent law.
This law proposed that during transfer of food energy from
one trophic level to the other, only 10% is stored at higher
trophic and the rest 90% is lost in respiration,
decomposition and waste in the form of heat (Figure 39.8).
For example, 5000 jules fall on leaves, it will convert only
50 jules into the chemical form (food).
It will be eaten by rabbit, he will get only 5 jules (10% of 50
jules) on next trophic level.
Rabbit will be consumed by carnivorous and they can be
able store only 0.5 jules (10% of 5 jules).
Succession Ecosystem changes over time and space, then
areas without life on earth can be filled with living beings.

This changing nature of communities and their ability to

recover from disturbance in ecosystem is called ecological
succession. There are two stages of succession
Permanent alteration of existing landforms/ topography – by
creating of dumps, deep voids, infrastructure development, haul
roads, waste rock dumps, mine fire, fragmentation of habitat,
introduction of exotic species, etc.

Flora and vegetation Direct impacts mainly occur through

clearing for the mine, waste rock dumps, processing plant, tailings
storage facility and associated infrastructure.

Fauna: Impact either primary or secondary.

Primary impact is the direct destruction of habitats through land

clearing and earthmoving activities.

Secondary impacts relate to activities with varying degrees of

disturbance beyond the immediate point where mining is taking
place, such as access and haul roads, power transmission line,
erection of light towers, and other infrastructure.
Surface water hydrology and groundwater:

Development of the open pits, stockpiles, waste rock dumps,

tailings storage facilities, processing plant and infrastructure
often interrupt some of the natural drainage paths.

Interference with drainage patterns may result in deprivation of

water to drainage systems downstream of the mining
developments or localized effects on some vegetation.

Soil and water contamination: Chemical reactions in waste rock

and tailings have the potential to be detrimental to plant growth
and to result in contamination of both surface and groundwater.
Studying the patterns of the change in ecosystems in response
to natural or human disturbance is an important tool for learning
how to restore lands damaged by people.

Natural areas are subject to disturbances of many kinds.

These disturbances are not always or even usually human-

induced.
For example, natural disturbances such as storms and fires
have always been a part of the environment.

Such disturbances have existed for so long that animals and

plants have adapted to them to such an extent that the
landscape actually benefits in the long run.
When fires occur at natural rates and intensities, there are
some beneficial effects.
For example, trees in unburned forests appear more
susceptible to insect outbreaks and disease.
Thus, recent ecological research suggests that wilderness
depends on change and that ecological succession and
disturbances are continual processes that keep the
landscape dynamic.
Hence Succession plays an important role in restoration
and recovery of ecosystem.
One feature of succession is that the biological
community changes.
In early stages, biomass increases and so does the
diversity of life forms.
In middle stages of succession, there are many species
and sizes of trees and a variety of other patterns that
occur.
Gross and net productions change during succession
in that while the gross production increases, the net
production decreases
 Chemical cycling also changes and the organic material in
the soil increases, as does the amount of chemical elements in
the soil and trees.
What the foregoing discussion shows is that natural
processes could restore a damaged habitat into its previous or
even into an improved state and that the environment overall is
self-sufficient.
However, the balance that is maintained is delicate.
Removal or addition of certain factors, for example, can disrupt
this balance and the result is an imbalance in the ecosystem. We
will touch upon this, next.
 The ecological footprint measures the demand upon our
natural resources and our available bio-capacity to generate
resources and provide services.
In order to achieve this; a survey is made in assessing the
biologically productive land and marine area required to
generate the enough resources for growing population and also
work out the corresponding waste.
At the end of the survey the data is categorized for food,
carbon, housing, goods and services along with level of
consumption that indicates total footprint number to sustain
world‟s population.
 Now a days ecological footprint is called as indicator of
environmental sustainability.

As it manages the resources throughout the economy;

it can be used to explore the sustainability of individual
lifestyles, organization groups, industrial sectors, cities and
regions, goods and services and even the nations as a whole.
Essentially, environmental impact assessment (EIA) is an
environmental decision support tool, which provides information
on the likely impacts of development projects to those who take
the decision as to whether the project should be authorised.

The purpose of an EIA is to determine the potential environmental,

social, and health effects of a proposed development, so that
those who take the decisions in developing the project and in
authorising the project are informed about the likely consequences
of their decisions before they take those decisions and are
thereby more accountable
It is intended to facilitate informed and transparent
decision-making while seeking to avoid, reduce or mitigate
potential adverse impacts through the consideration of
alternative options, sites or processes

Environmental Impact Assessment (EIA) is a systematic

and integrative process for considering possible impacts
prior to a decision being taken on whether or not a proposal
should be given approval to proceed (Wood 2003).
EIA TYPES
THANK YOU