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Fragile Environments


Fragile Environments The last Unit Guys! (Only the coursework exam to do after Christmas) – PowerPoint PPT presentation

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Title: Fragile Environments

Fragile Environments
  • The last Unit Guys!
  • (Only the coursework exam to do after Christmas)

What does it involve?
So today, we start with
  • A brief look at biomes or ecosystems different
    words that mean the same thing.
  • A quick look at some of the issues we will study
    in more depth later
  • A definition of sustainability
  • An example of a group who continue to live
  • The causes of soil erosion

Fragile environments and sustainability
  • Unique biomes/ecosystems each with specific
    characteristics. They are climatically and
    geographically defined areas. They have similar
    ecological communities of plants, animals, and
    soil organisms. They have related plant families
    which are alike in structure (such as trees,
    shrubs, and grasses), the same leaf types (such
    as broadleaf and needle-leaf), plant spacing
    (forest, woodland, savannah), and climate..
  • The map opposite is interactive on
  • Bright green rainforest
  • Orange savannah
  • Yellow desert
  • Brown Chapa (Mediterranean)
  • Khaki deciduous forest
  • Dark Green boreal forest (Coniferous)
  • Grey Tundra
  • Purple alpine (mountainous)

Fragile environments and sustainability
  • These biomes depend on climate, rocks, soils,
    natural vegetation, animals and human activity.
  • Man has changed most of the Earths surface but
    there are still those indigenous groups who live
    in harmony with their environment
  • People have always made use of the ecosystems to
    provide themselves with food, fuel and building
    materials, and there are groups that still do
    that in a way that does damage the environment

People have always made use of the ecosystems to
provide themselves with food, fuel and building
  • The Awá are a small tribe living in the Amazon
    state of Maranhão. They are one of only two
    nomadic hunter-gatherer tribes remaining in
  • Some live in tiny family groups living in the
    rainforest outside legally recognized territories
    while approximately 40 individuals living in the
    Araribóia reserve.

People have always made use of the ecosystems to
provide themselves with food, fuel and building
  • If the Awá are to survive it is vital that their
    forest home remains intact and that they are not
    exposed to diseases transmitted by outsiders and
    to violence at their hands.
  • The Awá hunt, fish and gather forest produce such
    as nuts and fruits. Those who are nomadic live in
    highly mobile, self-sufficient groups of no more
    than 20-30 people.
  • As they travel, they keep the embers of their
    fires lit, relighting the fire as they arrive at
    their destination.

You can see more about these people on
  • http//
  • These tribes are part of a group labelled by
    various organisations such as Survival
    International, as uncontacted.
  • This does not necessarily mean that no outsider
    has ever seen them but it does mean that they
    have chosen to (and been supported by their
    governments) to live their own lives, with little
    or no input from outside.
  • Although if you follow the link, you will see
    that there are problems there too.

What are fragile environments?
  • Fragile environments are those biomes that under
    threat form change, damage or unsustainable use.
  • Although natural hazards, such as earthquakes,
    volcanoes, hurricanes, can cause a lot of
    damage, it is mainly human intervention that
    causes the most even seemingly natural events
    like floods and droughts are often made worse by

What are the issues?
  • Issues include
  • Undeveloped land is becoming scarcer as there is
    less undeveloped land available, the pressure
    increases on that that remains.
  • Protecting biodiversity (plants and animals) is
    more difficult we want to conserve that which
    we have but our desire to visit and see these
    areas is destroying them
  • Desert edges are becoming deserts through
    overgrazing and the removal of trees/shrubs which
    give rise to soil erosion, and the decreasing
    rainfall all combine to turn productive farmland
    into useless scrub.

What are the issues?
  • At the other end of the scale, deforestation of
    rain forests flows as the natural resources are
  • Illegal logging - 20 of the timber supply comes
    from illegal sources.
  • "Europe remains one of the main markets for
    illegal timber despite a 2003 EU action plan to
    combat illegal logging and related trade. Strong
    legislation to halt illegal timber trade and to
    decrease Europe's devastating impact on the
    world's forests should be adopted as a bare
    minimum - there is no time to lose," said
    Friedrich Wulf from ProNatura / Friends of the
    Earth Switzerland.

What else are we doing wrong?
  • Human and industrial waste pollute rives and
  • At sea, oil spills and deliberate toxic dumping
    causes widespread pollution.
  • Many local problems cause more widespread
  • Traffic in towns causes congestion and pollution.
  • Building new roads can solve these problems but
    causes others such as the destruction of rural
  • This can also lead to more traffic and acid rain,
    production of greenhouse gases and global climate

What else are we doing wrong?
  • If the diversity and the environment are to
    survive then careful management is necessary.
  • Local decisions have international effects.
  • International co-operation and legislation will
    be the only way to resolve the issues which will
    help us work together and sustain the world for
    future generations.

What else are we doing wrong?
  • This diagram shows some of the ways the world is
    being used in an unsustainable way.

What else are we doing wrong?
  • "Sustainable development is development that
    meets the needs of the present without
    compromising the ability of future generations to
    meet their own needs". World Commission on
    Environment and Development.
  • This means that if you need timber, for example,
    you must replant as much as you cut down.
  • If resources are managed sustainably, then
    present and future demands for food, shelter,
    clothing and recreation will be met.

Soil erosion
  • One of the major problems in fragile environments

What are the causes of soil erosion
  • There are 3 main physical causes of erosion
  • Sheet erosion
  • Gulley erosion
  • Wind erosion
  • And then accelerated or human induced erosion

Sheet Erosion
  • Where there is sufficient rainfall, exposed soil
    will be moved downhill as a mass movement sheet
  • Raindrop impact is the major cause of soil
    particle detachment which can result in the
    particles moving down slope as sheet erosion
    during a rainfall event.
  • Sheet erosion is the removal of fairly uniform
    layer of surface material from the land surface
    by continuous sheets of runoff water rather than
    concentrated into channels.

Sheet Erosion
  • Heavy rain that leads to a sheet of water
    removing a more or less uniform layer of fine
    particles from the entire surface of an area is
    sheet erosion. It often includes the best soil
    particles along with much of the organic matter.
  • While it causes severe erosion, it is very
    difficult to see, as the amount removed is often
    slight from any particular spot. Notice how these
    ploughed areas in Romania have been covered by
    the sheet erosion.

Gulley Erosion
  • More frequently, the water gathers together and
    quickly erodes a channel. This is called gulley
  • The example below can be seen in it all its glory
    in the blog (http//
    2/the-power-of-water/ ). It was named locally as
    the Durham Great Canyon and appeared literally
    over night in a cornfield.

Gulley Erosion
  • You may also see mention of rill erosion which is
    a diminutive example of something similar.
  • This is an example of a rill forming during one
    particularly heavy rainstorm in Autumn 2008 in
    the field behind our house notice the murky
    colour of the water that is soil erosion

Wind erosion
  • Soil erosion by wind may occur wherever dry,
    sandy or dusty surfaces, inadequately protected
    by vegetation, are exposed to strong winds.
  • Erosion involves the picking up and blowing away
    of loose fine grained material within the soil.

Short-term effects of wind erosion
  • Dust storms are very disagreeable and also the
    land is robbed of its long-term productivity
    (humus (vegetable matter) is lighter and likely
    to be removed first).
  • Crop damage, especially of young crops, can be
  • Either the roots are exposed as the wind blows
    away the top soil or else wind blown soil from
    elsewhere cover the seeding up either way the
    crop will be lost.

Long term effects of wind erosion
  • Long term damage is even greater.
  • Finer soil fractions (silt, clay, and organic
    matter) are removed and carried away by the wind,
    leaving the coarser fractions behind.
  • This sorting action not only removes the most
    important material from the standpoint of
    productivity and water retention, but leaves a
    more sandy, and thus an even more erodible, soil
    than the original.

The Impacts of humans on soil erosion
  • The most common human impact is due to population
  • This leads to increased pressure on the land and
    its resources.
  • Overgrazing is a major problem.
  • This causes vegetation loss and makes the soil
    much more vulnerable to erosion without the
    protective net of roots to withstand the
    pressures of water and wind.
  • Intensive cultivation can cause loss of nutrients
    and soil exhaustion. This may lead to
  • Another major cause of deforestation is the
    cutting down of trees for fuel wood or clearing
    it for agriculture.
  • In practice the causes of soil erosion are
    usually a combination of physical and human
    causes, as you see below.

An example The impacts of human activity and the
natural environment on National Parks
  • Most types of vegetation can withstand some
    disturbance and will recover naturally in time.
    The level of recreational disturbance which an
    area can tolerate without damage is described as
    its recreational carrying capacity.
  • The effects of recreation are not evenly spread.
    They are mainly found around places such as car
    parks, pony trekking routes, river crossing
    points, riverside picnic sites and on popular
    walking routes such as from a car park to a a

An example The impacts of human activity and the
natural environment on National Parks
  • Erosion is often caused by a combination of
  • Livestock grazing, farmers vehicles, hikers
    boots, horse riding and mountain bikes can all
    play a part in damaging the vegetation.
  • These factors, combined with natural forces,
    determine the extent of erosion and the speed at
    which it occurs.

What are the problems?
  • Erosion Problems
  • Trampling by walkers, climbers and livestock has
    exposed the soil around the base of the rocks.
  • People have driven vehicles onto the open land
    causing damage around the car park and roadsides.
  • Popular routes used by thousands of visitors
    which created erosion gullies and muddy
    impassable ground
  • Paths suffer from both narrowing by gorse
    encroachment and increased erosion from water

What can be done about it?
  • Techniques Used to improve the situation
  • Low grassed banks have been created beside the
    roads and in car parks
  • Access using boulders can block off grass parking
    areas in the winter when the ground is soft and
    more vulnerable to damage from tyres. This both
    protects the grass and reduces the number of
    people using the area.
  • These gullies have been filled in and the turf
    restored on the steeper parts of the path.
  • Gorse clearance (burning and mowing) has been
    undertaken so as to widen or increase the number
    of paths and so spread the load of walkers
    walking between the two points.
  • Grassed over, open drainage gullies have been
    created to divert rainwater away from the well
    used paths and reduce the possible gully erosion.
  • Granite paving slabs and rocks have been used to
    create a solid base on a wet, boggy part of the
  • Education by way of information sheets and
    notices are used to ask people to behave in a way
    that protects the environment.

In summary
  • What is an ecosystem or biomes?
  • What are the Awá people an example of? Where are
    they found?
  • We mentioned 4 main issues. What are they?
  • Can you think of some other things that we are
    doing to damage the environment?
  • What is sustainable development?
  • What are the causes of soil erosion?
  • What is the Durham grand Canyon an example of?
  • What is the short term impacts of wind erosion?
  • What are the impacts of humans on soil erosion?
  • What are the causes of soil erosion in National