Fragile Environments

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Fragile Environments

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

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What does it involve?
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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
  sustainably
• The causes of soil erosion

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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
  http//ih-igcse-geography.wikispaces.com/7.1Fragil
  eenvirnmentsandsustainability

• Bright green rainforest
• Orange savannah
• Yellow desert
• Brown Chapa (Mediterranean)
• Khaki deciduous forest
• Dark Green boreal forest (Coniferous)
• Grey Tundra
• Purple alpine (mountainous)

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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

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People have always made use of the ecosystems to
provide themselves with food, fuel and building
material

• 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
  Brazil.
• Some live in tiny family groups living in the
  rainforest outside legally recognized territories
  while approximately 40 individuals living in the
  Araribóia reserve.

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People have always made use of the ecosystems to
provide themselves with food, fuel and building
material

• 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.

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You can see more about these people on

• http//www.survivalinternational.org/tribes/awa
• 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.

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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
  man.

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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.

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What are the issues?

• At the other end of the scale, deforestation of
  rain forests flows as the natural resources are
  exploited.
• 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.

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What else are we doing wrong?

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

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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.

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What else are we doing wrong?

• This diagram shows some of the ways the world is
  being used in an unsustainable way.

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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.

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Soil erosion

• One of the major problems in fragile environments

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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

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Sheet Erosion

• Where there is sufficient rainfall, exposed soil
  will be moved downhill as a mass movement sheet
  erosion
• 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.

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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.

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Gulley Erosion

• More frequently, the water gathers together and
  quickly erodes a channel. This is called gulley
  erosion.
• The example below can be seen in it all its glory
  in the blog (http//lindym.wordpress.com/2009/07/2
  2/the-power-of-water/ ). It was named locally as
  the Durham Great Canyon and appeared literally
  over night in a cornfield.

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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

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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.

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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
  serious.
• 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.

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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.

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The Impacts of humans on soil erosion

• The most common human impact is due to population
  growth.
• 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
  deforestation.
• 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.

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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
  viewpoint.

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An example The impacts of human activity and the
natural environment on National Parks

• Erosion is often caused by a combination of
  factors.
• 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.

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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
  runoff.

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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
  path
• Education by way of information sheets and
  notices are used to ask people to behave in a way
  that protects the environment.

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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
  Parks?