Maintaining Biodiversity (AQA GCSE Biology): Revision Note

Positive & negative human impact

• The increasing human population and the activities of humans (including waste production, peat bog destruction, deforestation and human contributions to global warming) are causing a reduction in global and ecosystem-level biodiversity

• These activities are considered as negative human interactions with ecosystems

• There are, however, ways in which humans can interact positively with ecosystems

Methods to protect biodiversity

• Breeding programmes for endangered species

  • Breeding programmes have been set up to save endangered species from extinction

  • Endangered species are bred in captivity

  • Individuals can then be released back into their native habitats to help support or in some cases re-establish endangered wild populations.

• Protection and regeneration of rare habitats

  • Protection of vulnerable habitats such as rainforests, mangroves, heathland and coral reefs helps to preserve the biodiversity within them and stabilise these ecosystems

• Reintroduction of field margins and hedgerows in agricultural areas where farmers grow only one type of crop

  • A single crop-type (known as monocultures) can only support a low level of biodiversity

  • Hedgerows, as well as the wild flowers and grasses that grow when field margins are created, support a high level of biodiversity

• Reduction of deforestation and carbon dioxide emissions by some governments

  • Deforestation results in habitat destruction and increased carbon dioxide in the atmosphere

  • Reducing deforestation and carbon emissions will reduce the rate of current global warming, which is threatening habitats and biodiversity

• Recycling resources rather than dumping waste in landfill

  • Reduces the amount of waste produced and the amount of space required for landfill sites, reducing habitat destruction

  • Reduces the rate we are using up natural resources, reducing habitat-destroying activities such as quarrying and mining

Pressures on maintaining biodiversity

• The cost of programmes:

  • Protecting biodiversity can be very expensive

  • For example, the land used for field margins could be used by farmers to grow crops and sell them – governments sometimes pay farmers a subsidy to make up for the lost money

  • It costs money to check that programmes designed to maintain biodiversity are actually being followed

• Protecting food security:

  • Land that is protected to maintain biodiversity could instead be used for farming – this can cause conflict in areas where there are food shortages

  • Sometimes organisms seen as a threat by farmers (e.g. locusts and wolves) are killed to protect crops and livestock – this can negatively affect food chains / biodiversity and can cause conflict when species that are already under threat due to hunting or habitat loss are involved (e.g. lions in parts of Africa)

• The development of society:

  • Increasing amounts of land are required to sustain the increasing human population

  • For example, land required for new housing developments or for new agricultural land in developing countries

  • This high demand means that land with undisturbed habitats and high biodiversity is increasingly being used for development