A V K KAMMALAMA
COLLEGE
Environmental science
SAMA KHAN
Guest lecturer
A V KAMMALAMA COLLEGE
NATURAL RESOURCES :
All the materials and energy essential for the
survival and welfare of living organisms including
humans are provided by nature.
These resources are called as natural resources.
Natural resources are of two types:
1.Renewable resources
2.Non – renewable resources
Renewable resources:
These resources can be replenished and do not
change the ecological balance. The cut trees an be
grown, soil forms again and animals reproduce
themselves.
Ex Solar energy, Wind, Hydro ( water)
Non – renewable resources:
Resources which once used up will be exhausted
forever. Over exploitation natural resources that
are limited in stock may cause scarcity even
renewable resources such as water, forests require
long period of time for replenishment.
Ex : Coal , Petrol , Natural gas.
LAND RESOURCES :
Land is a major constitute of lithosphere and is the
source of many materials essential to man and
other organsms. Earth’s ¼ area is formed by land
which is largely covered with the following
elements.
1.Natural forest
2.Grasslands
3. Wetlands
NATURAL FORESTS:
They are the eco-systems predominantly
composed od trees established by natural
regeneration, rather than human planting.
GRASS LANDS:
They are also called as Rangelands. They provide
forage and habitat to domestic animals and
wildlife. Natural grass lands occur where rainfall is
inter mediate between that of Desert Land and
Forest Land.
A well developed grass land and community
contains species with different temperature
adaptations and one group growing in the cool part
of the season (That is Spring, Winter) And another
in hot part ( That is Summer).
USES:
In rural areas of our country dried hay is obtained
from grass lands, particularly from the grasses
that’s used for fuel material.
Large herbivores are characteristic feature of grass
lands.
TERABHUMI:
WET LANDS:
They are the low lying areas usually covered by
shallow water and have a characteristic soil and
water tolerant vegetation. They maybe either of
FRESH WATER and SALT WATER.
FRESH WATER:
*They include marshes, (grass like plants which
dominate)
*Swamps where trees or shrubs dominate.
* Wet lands are highly productive and provide food
and habitat to support a wide variety of organisms.
* They control flooding by holding excess water
and the flood water is stored in Wet lands, then
drains slowly back into the rivers providing a
steady flow of water throughout the year.
* They also serve as (ground water recharging
areas), They are helpful in cleaning and purifying
water run off. It also provides important
commercial products such as blackberries,
blueberries etc..
FORAGE: Food
SALT WATER (Wet Lands):
* Coastal wet lands are also known as Wet Lands.
They include highly productive, they provide food
and habitat for large number marine organisms.
* Whereas physical features such as Salinity and
temperature are much more variable shore than in
the sea.
* Food conditions are much more better.
Tidal Action promotes rapid circulations of
nutrition and food and aids in the rapid
removal of waste products of Metabolism.
WETLAND CONSERVATION
Conservationists and trained marine
environmental engineers have become
alarmed by the needless destructions of
coastal resources.
So, ultimately it may be necessary to set up
some kind of conservation plan so that the use
of such areas by man can be placed on sound
ecological basis
LAND-USE CHANGE:
As growing human population places additional
burdens on land due to increased needs of
food, energy, natural resources, economic
development, and space pressure increases to
convert natural habitats for other uses.
Right now, 37 percent of Earth’s landmass
excluding Antarctica is already used for food
production.
These land use change are one of the greatest
threats of remaining biological diverse
habitats, and the organisms that make up
these eco-systems.
Conservatism efforts for critical for protecting
biodiversity as well as for the natural solutions
to mitigate green gas emissions, such as
planting more trees and keeping the carbon
rich and forests that currently store carbon
intact. (Mitigate- make it more severe).
LAND DEGRADATION:
Man has had a persistent history of misuse of
grasslands and virtue of allowing overgrazing
and overploughing . The result is that many
grass lands are now man made deserts.
The conversion of grasslands to desert is called
is Desertification.
Degradation of destruction of grass lands are
mainly are related to overpopulation. To
enhance food production, grass lands
possessing fertile soil ploughed and converted
to agricultural lands.
In India grassland areas are frequently
overgrazed. For example the number of grazing
in arid and semi-arid regions has been found to
be 2-10 times greater than the capacity of the
grasslands to feed the animals.
The lack of plant cover due to overgrazing soil
causes soil erosion. When overgrazing occurs
in combination with droughts the deserts are
related.
Grasslands to desert, desert to desertification,
Desertification to Degradation, Degradation to
Soil Erosion.
Over grazing occurs combines with droughts
the deserts are resulted.
SOIL EROSION:
The erosion literally means to ‘wearing away’.
In sol erosion the fertile soil surfaces are
detached and removed from their original
places and deposited to other places.
According to Fox (1950), The soil erosion
covers a wide range of physical and chemicals
action such as removal of soluble matter,
chemical changes, disintegration by forests or
by the rapid changes of temperature.
EFFECTS:
Due to uprooting of trees, scarcity of timber
and fuel wood.
Loss of soil stability and Fertility.
Shortage of Fodder.
Formation of sand dunes.
DESERTIFICATION :
Desertification is the process which turns
productive into non- productive desert as a result
of poor land management. Desertification occurs
mainly in semi- arid and arid areas (average annual
rainfall less than 600 mm) bordering on deserts. In
the Sahel, (the semi arid area south of the Sahara
Desert) ,for example, the desert moved 100 km
southwards between 1950 and 1975.
CAUSES OF DESERTIFICATION:
Overgrazing is the major cause of
desertification worldwide. Plants of semi -arid
areas are adopted to being to be eaten by
sparsely scattered, large, grazing mammals
which move in response to patchy rainfall
common to these regions. Early human
pastoralists living in the semi -arid areas
copied the natural system. They moved their
small group of animals in response to food and
water availability. Such regular movement
prevented overgrazing of the fragile plant
cover.
Cultivation of marginal lands ie., lands on
which there is a high risk of crop failure and
very low economic return, for example some
parts of South Africa where maize is grown.
Destruction of vegetation in arid areas , often
for fuel wood.
Poor grazing management after accidental
burning of semi-arid vegetation.
Incorrect irrigation practices in arid areas can
cause salinization, ( the build up of salts in the
soil ) which can prevent plant growth.
When the practices described above coincide
with drought, the rate of desertification increases
dramatically.
Increasing human population and contribute to
desertification as poor people may be forced to
overuse their environment in the short term,
without the ability to plan the long term effects
of their actions. Where livestock has a social
importance beyond food, people might may be
reluctant to reduce their stock members.
EFFECTS OF DESERTFICATON:
Desertification reduces the ability of land to
support life affecting wild species, domestic
animals, agricultural crops and people. The
reduction in plant covers that accompanies
desertification that leads to accelerated soil
erosion by wind and water. South Africa loosing
approximately 300-400 million tones of top soil
every year. As vegetation cover and soil layer are
reduced, rain drop impact and run off increases.
Water is lost of the land instead of soaking into
the soil to provide moisture for plants. Even long-
lived plants that would normally survive droughts
die. A reduction in plant cover also results in the
reduction of quantity of humus and plant
nutrients in the soil, and plant production drops
further. As protective plant disappears, floods
become more frequent and more severe.
Desertification is self-reinforcing, i.e. one the
process has started, and conditions are set for
continual deterioration.
