ASSIGNMENT
TOPIC: NATURAL RESOURCES-FOREST AND MANGROOVES
SUBMITTED TO, SUBMITTED BY,
Mrs.RADHA ARATHI KRISHNAN.U
NATURALSCIENCE
SUBMITTED ON , KUCTE ARYAD
22-06-2014
NO:100
INDEX
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CONTENT
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PAGE
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1
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INTRODUCTION
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2
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2
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CONTENT
DEVELOPED
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3-17
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3
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CONCLUSION
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18
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4
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REFERENCE
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19
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INTRODUCTION
Our planet is unique in
the solar system as it provides ideal conditions and for the entire biotic
life. Though efforts are being made to explore other planets, it may be very
difficult for the future man to find a planet like the earth for colonizing
people. The earth will still remain the essential base for human activities.
It we exploit it resource then the ultimate fate of mankind will indeed be
calamitous.
The natural resources on
which we depend are categorized differently. It may
be based on their biotic and abiotic or based on the renewability and
nonrenewability. Natural resources are materials are naturally occurring and
we use it directly or with refinement or modification, or resource that is
directly available for use from nature ,which includes fresh water, fresh
air, soil, land, forest, grasslands, fisheries, minerals etc. Natural
resources provide fundamental life support, in the form of both consumptive
–like grains, meat, fish etc.
A forest is best defined as an ecosystem
or assemblage of ecosystems dominated by trees and other woody vegetation.
The living part of forest include trees, shrubs vines, grasses and other
herbaceous plants, mosses, fungi, insects, mammals, birds, reptiles,
amphibians and micro organisms etc. The wetlands are ecotones or transitional
zones that occupy an intermediate position between dry land and open water.
Wetlands are often referred as the ‘kidneys’ of the earth.
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CONTENT DEVELOPNT
Natural resources occur
naturally within environments that
exist relatively undisturbed humanity, in a natural form.
A natural resources
often characterized by amounts of biodiversity and geodiversity existent
in various ecosystems.
Natural resources are derived from the environment. Some of them are essential
for our survival while most are used for satisfying our wants. Natural
resources may be further classified in different ways. Natural resources are
materials and components (something that can be used) that can be found within
the environment. Every man-made product is composed of natural resources (at
its fundamental level). A natural resource may exist as a separate entity such as
fresh water, and air, as well as a living organism such as a fish, or it may
exist in an alternate form which must be processed to obtain the resource such
as metal ores, oil, and most forms of energy.
There is much debate worldwide
over natural resource allocations; this is partly due to increasing scarcity
(depletion of resources) but also because the exportation of natural resources
is the basis for many economies. Some natural resources such as sunlight and
air can be found everywhere, and are known as ubiquitous resources. However,
most resources only occur in small sporadic areas, and are referred to as
localized resources. There are very few resources that are considered
inexhaustible (will not run out in foreseeable future) – these are solar
radiation, geothermal energy, and air (though access to clean air may not be).
The vast majority of resources are exhaustible, which means they have a finite
quantity, and can be depleted if managed improperly.
CLASSIFICATION
There are various
methods of categorizing natural resources, these include source of origin,
stage of development, and by their renewability. These classifications are
described below. On the basis of origin, resources may be divided into: Biotic – Biotic resources are obtained from
the biosphere (living
and organic material), such as forests and animals,
and the materials that can be obtained from them. Fossil fuels such
as coal and petroleum are
also included in this category
because they are formed from decayed organic matter.
Abiotic –
Abiotic resources are those that come from non-living, non-organic material.
Examples of abiotic resources include land,
freshwater, air and
heavy metals including ores such
as gold, iron, copper, silver,
etc.
Considering their stage
of development, natural resources may be referred to in the following ways:
Renewability is a very
popular topic and many natural resources can be categorized as either renewable
or non-renewable:
Renewable resources –
Renewable resources can be replenished naturally. Some of these resources, like
sunlight, air, wind, etc., are continuously available and their quantity is not
noticeably affected by human consumption.
Non-renewable resources –
Non-renewable resources either form slowly or do not naturally form in the
environment. Minerals are the most common resource included in this category.
By the human perspective, resources are non-renewable when their rate of
consumption exceeds the rate of replenishment/recovery; a good example of this
is fossil fuels.
FOREST
A
forest is best defined as an ecosystem or assemblage of ecosystems dominated by
trees and other woody vegetation. The living part of forest include trees,
shrubs vines, grasses and other herbaceous plants, mosses, fungi, insects,
mammals, birds, reptiles, amphibians and micro organisms etc. A forest, also referred to as a wood or the woods, is an area with a high density
of trees. As with cities, depending on various
cultural definitions, what is considered a forest may vary significantly in
size and have different classifications according to how and of what the forest
is composed. forest is usually an area filled with trees but any tall densely
packed area of vegetation may be considered a forest, even underwater
vegetation such as kelp forests, or non-vegetation such as fungi] and bacteria. Tree forests cover approximately 9.4 percent
of the Earth's surface (or 30 percent of total
land area), though they once covered much more (about 50 percent of total land
area). They function as habitats for organisms, hydrologic flow modulators, and soil conservers,
constituting one of the most important aspects of the biosphere.
A typical tree forest is composed of the
overstory (canopy or upper tree
layer) and the understory. The understory is
further subdivided into the shrub layer, herb layer, and also the moss layer
and soil microbes. In some complex forests, there is also a well-defined lower
tree layer. Forests are central to all human life because they provide a
diverse range of resources: they store carbon, aid in regulating the planetary
climate, purify water and mitigate natural hazards such as floods. Forests also
contain roughly 90 percent of the world's terrestrial biodiversity.
Forests can be found in all regions
capable of sustaining tree growth, at altitudes up to the tree line, except where natural fire frequency or other
disturbance is too high, or where the environment has been altered by human
activity.
Forests sometimes contain many tree species
only within a small area (as in tropical rain and temperate
deciduous forests), or relatively few species over large areas (e.g., taiga coniferous
forest). Forests are often home to many animal and plant species, and biomass per unit area is high compared to other
vegetation communities. Much of this biomass occurs below ground in the root
systems and as partially decomposed plant detritus..
Forests are differentiated from woodlands by the extent of canopy coverage: in a forest, the branches and
the foliage of separate trees often meet or interlock, although there can be
gaps of varying sizes within an area referred to as forest. A woodland has a
more continuously open canopy, with trees spaced farther apart, which allows
more sunlight to penetrate to the ground between them
TYPES OF FORESTS
Evergreen forest: Forest consisting
entirely or mainly of evergreen trees that retain green foliage all year round
Temperate deciduous
forest
: Distributed in North and South America
Rain forests : Forest in the tropic
found in the equatorial zone
Forests can be classified in different ways
and to different degrees of specificity. One such way is in terms of the
"biome" in which they exist, combined with leaf longevity of the
dominant species (whether they are evergreen or deciduous). Another distinction is whether the forests
are composed predominantly of broadleaf trees, coniferous (needle-leaved) trees, or mixed.
Temperate zones support both broadleaf deciduous forests (e.g., temperate deciduous forest) and evergreen coniferous forests (e.g.,temperate coniferous forests and temperate rainforests).
Warm temperate zones support broadleaf evergreen forests, including laurel forests.
Tropical
and subtropical forests
include tropical and
subtropical moist forests, tropical and subtropical dry forests, and tropical and subtropical coniferous
forests.
Physiognomy classifies forests based
on their overall physical structure or developmental stage (e.g. old growth vs. second growth).
Forests
can also be classified more specifically based on the climate and the dominant
tree species present, resulting in numerous different forest types (e.g.,
ponderosa pine/Douglas-fir forest).
FOREST
PLANTATIONS
Forest plantations, generally intended for the
production of timber and pulpwood increase the total area of forest
worldwide. Commonly mono-specific and/or composed of introduced tree species,
these ecosystems are not
generally important as habitat for native biodiversity. However, they can be managed in ways that
enhance their biodiversity protection functions and they are important
providers of ecosystem services such as maintaining nutrient capital, protecting watersheds and soil structure as well as storing
carbon. They may also play an important role in alleviating pressure on natural
forests for timber and fuel wood production
FOREST CATOGORIES
A temperate
deciduous broadleaf forest
Redwoods in old growth
forest
FOREST
LOSS AND MANAGEMENT
The scientific study of forest species and their interaction
with the environment is referred to as forest ecology, while the management of forests is often referred to
as forestry. Forest management has changed considerably over the last few centuries,
with rapid changes from the 1980s onwards culminating in a practice now
referred to as sustainable forest
management. Forest
ecologists concentrate on forest patterns and processes, usually with the aim
of elucidating cause-and-effect relationships. Foresters who practice sustainable forest
management focus
on the integration of ecological, social, and economic values, often in
consultation with local communities and other stakeholders.
Anthropogenic factors that can affect forests include
logging, urban sprawl, human-caused forest fires, acid rain, invasive species, and the slash and burn practices of swidden agriculture or shifting cultivation. The loss and re-growth of forest
leads to a distinction between two broad types of forest, primary or old-growth forest and secondary forest. There are also many natural factors that can cause changes
in forests over time including forest fires, insects, diseases, weather, competition between species,
etc. In 1997, the World Resources Institute recorded that only 20% of the
world's original forests remained in large intact tracts of undisturbed forest These
maps represent only virgin forest lost. Some regrowth has occurred but not to
the age, size, or extent of 1620, due to population increases and food
cultivation
The opposite problem from flooding
has plagued national forests, with loggers complaining that a lack of thinning
and proper forest management has resulted in large forest fires.
Old-growth forest contains mainly natural patterns of biodiversity in
established several patterns, and they contain mainly species native to the
region and habitat. The natural formations and processes have not been affected
by humans with a frequency or intensity to change the natural structure and
components of the habitat. Secondary forest contains significant elements of
species which were originally from other regions or habitats.
Smaller areas of woodland in cities may be managed as Urban forestry, sometimes within public parks. These are often created for
human benefits; Attention
Restoration Theory argues that spending time in nature reduces stress and
improves health, while forest schools and kindergartens help young people to develop
social as well as scientific skills in forests. These typically need to be
close to where the children live, for practical logistics.
MANGROOVES
Mangroves are
various types of trees up to medium height and shrubs that
grow in saline coastal
sediment habitats in the tropics and
subtropics –
mainly between latitudes 25° N
and 25° S. The remaining mangrove forest areas of the world in 2000 was
53,190 square miles (137,760 km²) spanning 118 countries and territories. The word is used in at least three
senses: (1) most broadly to refer to the habitat and entire plant assemblage or mangal, for which the terms mangrove forest biome, mangrove swamp andmangrove forest are also used, (2) to refer to all
trees and large shrubs in the mangrove swamp, and (3) narrowly to refer to the
mangrove family of
plants, the Rhizophoraceae,
or even more specifically just to mangrove trees of the genus Rhizophora.
The term "mangrove" comes to English
from Spanish (perhaps by way of Portuguese), and is likely to originate from Guarani. It was earlier
"mangrow" (from Portuguese mangue or
Spanish mangle), but this word was corrupted
via folk etymology influence
of the word "grove". The mangrove biome, or
mangal, is a distinct saline woodland or shrubland habitat
characterized by depositional coastal
environments, where fine sediments (often with high organic content) collect in
areas protected from high-energy wave action. Mangroves dominate three-quarters
of tropical coastlines.The saline conditions tolerated by various mangrove
species range from brackish water,
through pure seawater (30
to 40 ppt(parts
per thousand)), to water concentrated by evaporation to over twice the salinity of ocean seawater (up to 90 ppt).An
increase in mangroves has been suggested for climate change mitigation.
ECOLOGY
Mangrove swamps are found in tropical and subtropical tidal areas. Areas where mangal occurs include estuaries and marine shores. The intertidal existence to which these trees are adapted represents the major
limitation to the number of species able to thrive in their habitat. High tide brings
in salt water, and when the tide recedes, solar evaporation of the seawater in
the soil leads to further increases in salinity. The return of tide can flush
out these soils, bringing them back to salinity levels comparable to that of
seawater. At low tide, organisms are also exposed to increases in temperature
and desiccation, and are then cooled and flooded by the tide. Thus, for a plant
to survive in this environment, it must tolerate broad ranges of salinity,
temperature, and moisture, as well as a number of other key environmental
factors-thus only a select few species make up the mangrove tree community.
About 110 species are considered "mangroves", in the
sense of being a tree that grows in such a saline swamp, though only a few are from the mangrove
plant genus, Rhizophora. However, a given mangrove swamp typically features only a
small number of tree species. It is not uncommon for a mangrove forest in the
Caribbean to feature only three or four tree species. For comparison, the
tropical rainforest biome contains thousands of tree species, but this is not
to say mangrove forests lack diversity. Though the trees themselves are few in
species, the ecosystem these trees create provides a home for a great variety
of other organisms.
Mangrove plants require a number of physiological adaptations to
overcome the problems of anoxia, high salinity and frequent tidal inundation. Each species has its own solutions to these problems; this may
be the primary reason why, on some shorelines, mangrove tree
species show distinct zonation. Small environmental variations within a
mangal may lead to greatly differing methods for coping with the environment.
Therefore, the mix of species is partly determined by the tolerances of
individual species to physical conditions, such as tidal inundation and
salinity, but may also be influenced by other factors, such as predation of
plant seedlings by crabs.
Once established, mangrove roots provide an oyster habitat and
slow water flow, thereby enhancing sediment deposition in areas where it is
already occurring. The fine, anoxic sediments under mangroves act as sinks for
a variety of heavy (trace) metals which colloidal particles in the sediments scavenged from the water. Mangrove removal
disturbs these underlying sediments, often creating problems of trace metal
contamination of seawater and biota.
Mangrove swamps protect coastal areas from erosion, storm , and
tsunamis. The mangroves' massive
root systems are efficient at dissipating wave energy., they slow down tidal
water enough so its sediment is deposited as the tide comes in, leaving all
except fine particles when the tide Webb. In this way, mangroves build their
own environments. Because of the
uniqueness of mangrove ecosystems and the protection against erosion they
provide, they are often the object of conservation programs, including national biodiversity action plans.
However, mangrove swamps' protective value is sometimes
overstated. Wave energy is typically low in areas where mangroves grow, so their effect on erosion can only be
measured over long periods. Their
capacity to limit high-energy wave erosion is limited to events such as storm
surges and tsunamis. Erosion
often occurs on the outer sides of bends in river channels that wind through
mangroves, while new stands of mangroves are appearing on the inner sides where
sediment is accruing.
The unique ecosystem found in the intricate mesh of mangrove roots offers a quiet marine region for young organisms. In areas where
roots are permanently submerged, the organisms they host include algae, barnacles, oysters, sponges, and bryozoans, which all require a hard surface for anchoring while they
filter feed. Shrimps and mud lobsters
use the muddy bottoms as their home Mangrove crabs mulch on the mangrove leaves, adding nutritients to the mangal
muds for other bottom feeders. In
at least some cases, export of carbon fixed in mangroves is important in
coastal food webs.
BIOLOGY
Of the recognized 110 mangrove species, only about 54 species in 20
genera from 16 families constitute the "true mangroves", species that occur almost exclusively in mangrove
habitats. Demonstrating convergent evolution,
many of these species found similar solutions to the tropical conditions of
variable salinity, tidal range (inundation), anaerobic soils and intense sunlight. Plant biodiversity is generally
low in a given mangal this is especially true in higher latitudes and in the
Americas. The greatest biodiversity occurs in the mangal of New Guinea, Indonesia and Malaysia
ADAPTATION TO LOW OXYGEN
A red mangrove
Red mangroves, which can survive in the most inundated areas, prop themselves
above the water level with stilt roots and can then absorb air through pores in
their bark (lenticels). Black mangroves live on higher ground and make many pneumatophores (specialised root-like structures which stick up out of the soil
like straws for breathing) which are also covered in lenticels. These "breathing tubes" typically reach heights of
up to 30 cm, and in some species, over 3 m. The four types of
LIMITING
SALT INTAKE
Red mangroves exclude salt by having significantly impermeable
roots which are highly suberised, acting as an ultrafiltration mechanism to exclude sodium salts from the rest of the plant.
Analysis
of water inside mangroves has shown 90% to 97% of salt has been excluded at the
roots. In a frequently cited concept that has become known as the
"sacrificial leaf", salt which does accumulate in the shoot then
concentrates in old leaves, which the plant then sheds. However, recent
research suggests the older, yellowing leaves have no more measurable salt
content than the other, greener leaves Red
mangroves can also store salt in cell vacuoles.
LIMITING WATER LOSS
Because of the limited fresh water available in salty intertidal
soils, mangroves limit the amount of water they lose through their leaves. They
can restrict the opening of their stomata (pores on the leaf surfaces, which exchange carbon dioxide gas and water vapour during photosynthesis). They also vary the
orientation of their leaves to avoid the harsh midday sun and so reduce
evaporation from the leaves.
NUTRIENT UPTAKE
The biggest problem mangroves face is nutrient uptake. Because
the soil is perpetually waterlogged, little free oxygen is available. Anaerobicbacteria liberate nitrogen gas, soluble iron, inorganic phosphates, sulfides,
and methane,
which make the soil much less nutritious.neumatophores (aerial roots) allow mangroves to absorb gases directly from the
atmosphere, and other nutrients such as iron, from the inhospitable soil.
Mangroves store gases directly inside the roots, processing them even when the
roots are submerged during high tide.
INCREASING
SURVIVAL OF OFFSPRING
In this harsh
environment, mangroves have evolved a special mechanism to help their offspring
survive. Mangrove seeds are
buoyant and are therefore suited to water dispersal. Unlike most plants, whose
seeds germinate in soil, many mangroves (e.g. red mangrove) are viviparous, whose seeds germinate while still attached to the parent tree.
Once germinated, the seedling grows either within the fruit (e.g. Aegialitis, Avicenniaand Aegiceras), or out through the
fruit
EXPLOITATATION AND CONSERVATION
Approximately 35% of
mangrove area was lost during the last several decades of the 20th century (in
countries for which sufficient data exist), which encompass about half of the
area of mangroves.[52] The United Nations Environment Program &
Hamilton (2013), estimate that shrimp farming causes
approximately a quarter of the destruction of mangrove forests.
Mangroves have been
reported to be able to help buffer against tsunami, cyclones,
and other storms. One village in Tamil Nadu was
protected from tsunami destruction - the villagers in Naluvedapathy planted
80,244 saplings to get into the Guinness Book of World Records.
This created a kilometer-wide belt of trees of various varieties. When the
tsunami struck, much of the land around the village was flooded, but the
village itself suffered minimal damage.
CONCLUSION
Earth
is finite but it provides all the goods and service essential for the healthy
survival of mankind and other life form
on earth . We depend on earth to fulfill the basic needs. Conservation of
resources essential for the survival of man. The natural resources are over
exploited. It is necessary to have a control over it. Advancement of science
and technology has already done a lot of damage to the environment. Forest and
mangroves are the natural resources which helpful for the humans so we have the
duty for conserve it.
REFERENCCES
1.
Dr.Sreelathamma.R, Blossom R. Nair -
Recent Trends and Developments in Teaching and Learning
2.
Dr.A.PThomas,Dr.A.V George - Environmental
Biology Disaster Management and Toxicology
3.
Dr.Sheeba V.T -Foundation of
Environmental Economics
4.
en.wikipedia.org/wiki/natural resources
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