4.7.3 Biodiversity and the effect of human interaction on ecosystems

4.7.3.1 Biodiversity

Biodiversity

• Biodiversity is a measure of the variety of living organisms within a particular habitat, ecosystem, biome, or all over Earth.

Highly Biodiverse Environments

• A highly biodiverse environment will be very stable.
  • They will be able to adjust to change very easily.
  • This also indicates that the particular environment has “good biological health”.

Non-Biodiverse Environments

• In contrast, non-biodiverse environment will be very unstable.
  • Such ecosystems will find it very difficult to adjust to change.
  • This also indicates that the particular environment has “poor biological health”.

Human Improvements to Biodiversity

• Humans are attempting to improve biodiversity.
  • This is occurring as we have realised that it may be our only method of surviving.
  • We must maintain a high level of biodiversity in order to keep our species alive in the future.

4.7.3.2 Waste management

Population Growth

• The human population has increased exponentially over time.
  • The populations of countries such as India and China are expected to, or have already, reached a billion each.
  • Each year, there is an increase of around 75 million people.

Reasons For Population Growth

• The growth in population has generally occurred as our standards of living have increased.
  • There is a lower infant mortality rate and a higher life expectancy due to better healthcare facilities.

Curbing Population Growth

• China attempted the controversial, ‘One Child Policy’ as they realised that their supply was not meeting their demand.
  • There were not enough resources for the sheer number of people.

Population Growth and Pollution

• As the population grows, more and more resources are used and more and more energy is required.
  • For this, there is an increase in the use of fossil fuels and an increase in the waste produced.
  • This leads to an increase in pollution.

Pollution

• Pollution can take many forms:
  • Water
  • Air
  • Land

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Water Pollution

• There are many ways in which water pollution occurs.
  • When farmers use fertilisers, water can run off from their fields into early bodies of water during periods of heavy rain.
  • This can settle in the water leading to eutrophication.

The Process of Eutrophication

1. Fertilisers used by farmers.

2. Fertilisers are carried by rain water.

3. Fertilisers enter lakes and rivers.

4. Nitrogen spike kills aquatic animals.

5. Overgrowth of plants.

6. Large loss of aquatic animals.

Water Pollution

• In parts of the world with open sewers, human waste may enter the streams and rivers.
  • This can cause severe illness such as cholera.

Air Pollution

• As we burn more fossil fuels, we send more and more sulphur dioxide and carbon dioxide into the air.
  • These are greenhouse gases and lead to global warming.
  • Moreover, they can combine with water in the clouds to form acid rain.

Air Pollution

• This huge amount of air pollution has led to smog.
  • This can be dangerous to humans.
  • The lungs of people living in central London have been known to take a lot of damage due to the pollution.

• As the human population grows, there is an increase in the waste produced.
  • When you put something in your bin, it is more often than not placed in a landfill site.
  • Batteries cannot be disposed of in this way.
  • When they make their way into landfill, their acid can leak, polluting the land.

Effect on Biodiversity

• Pollution has a huge effect on biodiversity.
  • Our waste can have horrible effects on biodiversity, reducing the species diversity and so making our ecosystem far less stable.

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4.7.3.3 Land use

Displacing Other Species

• As society progresses, we build more and more buildings, farms, quarries and waste facilities.
  • In order to do this, we clear habitats.
  • This reduces biodiversity.

Peat Bogs

• Peat bogs are very diverse areas.
  • They are acidic, wet ecosystems, with very little light.
  • Extremophiles and other such creatures live here.
  • Due to their conditions, they are also known as carbon sinks, as they store a great
  • deal of carbon.

• Peat bogs are broken up to form compost for farming.
  • Moreover, they are burnt for fuel.
  • This is dangerous as it releases a lot of carbon dioxide into the atmosphere.
  • This is a greenhouse gas and a pollutant.

• As peat bogs are destroyed, habitats are ruined.
  • Species then die and so the biodiversity is reduced.
  • Our ecosystem then becomes systematically less stable.

4.7.3.4 Deforestation

Deforestation

• Deforestation is the clearing of forests (or other habitats such as glaciers) to make way for human settlements and farmland.
• Deforestation for farming has several severe consequences:
  • It ruins habitats
  • This loss of habitats causes extinction
  • The loss of trees leads to soil erosion.

Deforestation Ruins Habitats

• The biggest impact is habitat destruction.
  • Loss of habitat results in loss of shelter, food, water, and other resources that other  organisms need to survive.

Lost Habitats Cause Extinction

• Habitat destruction leads to extinctions and die offs of different species in the ecosystem.
  • This leads to loss of biodiversity which puts the ecosystem in a state of poor biological health.

Lost Trees Cause Soil Erosion

• Tree roots hold soil in place.
• Without tree roots, rain and wind can remove the soil from the area.
• This leads to loss of nutritional value of the soil, which impacts the growth of plants, which in turn impacts the entire ecosystem.

4.7.3.5 Global warming

Global Warming

• The use of fossil fuels leads to the greenhouse gas effect which in turn causes global warming.
  • Global warming causes the temperatures on Earth to increase drastically.

• Carbon dioxide and methane are greenhouse gases.
  • They act by insulating the earth, thus causing an increase in temperature over time.
  • These increases in temperature have had many negative consequences on the Earth.

Negative Effects of Global Warming

• Weather patterns have changed, thus changing migration patterns
• Tropical diseases have spread to regions without immunity
• The polar ice caps are melting, leading to a rise in sea level

Effects on Ecosystems

• Many plants and animals require very specific climates in order to survive.
  • Changing the climate results in a loss of suitable habitat which can cause these organisms to become extinct.

Effects on Ecosystems

• Organisms better suited to warmer temperatures can outcompete other animals for resources and habitats, which also results in a loss of biodiversity.
• Climate change can promote the proliferation of many disease-causing organisms such as mosquitoes, mould, viruses, bacteria, and other parasites.
  • This can harm not only other plants and animals, but also humans.

4.7.3.6 Maintaining biodiversity

Human Improvements

• We have considered the negative impacts of humans on the environment.
• This tutorial will look at a few of the positive measures put in place to increase biodiversity.

Breeding Programmes

• As habitats have been lost, humans are attempting to repair some of the damage.
  • Animals such as the Arabian oryx and the panda have been kept alive by breedin programmes in zoos.
  • Here, animals are looked after well and helped to breed to keep their species alive.

Protecting and Regenerating Habitats

• National parks and nature reserves are made in order to protect certain endangered habitats.

Hedgerows and Field Margins

• When farmers grow only one type of crop, hedgerows and field margins are replanted as they provide a great habitat for many organisms.
  • This increases biodiversity.

Reducing Deforestation and Carbon Emissions

• Reducing deforestation has led to an increase in the numbers of certain habitats.
  • This has increased biodiversity.
  • By reducing carbon emissions, there could be a reduction in global warming.

Recycling

• Recycling resources has reduced the amount of waste in landfill, which reduces land pollution.