It is widely recognised within the scientific community that the Earth is currently facing a biodiversity crisis due to human pressures

• This crisis is said to be anthropogenic as the causes are a consequence (direct or indirect) of human activity
  

The overarching cause of this crisis is the global growth of the human population, which places numerous strains on native populations:

• Overexploitation: Overfishing and excessive or unnecessary hunting may reduce population numbers below sustainable levels

• Urbanisation: Human construction can lead to a direct loss or a fragmentation of habitats – resulting in increased competition between native species

• Deforestation: The clearing of land for industry (timber, mining, etc.) or agriculture (farming) results in a consequent loss of native habitat

• Pollution: Microplastics, along with fertilisers and organic waste products, can cause ongoing damage to natural environments

• Climate Change: Greenhouse gases released via industrial processes are changing climate conditions and increasing ocean acidification

• Global Transport: Globalisation is increasing the spread of pests, pathogens (infectious diseases) and invasive species
  

  • An invasive species is an alien species that has been transferred to a new environment and has a detrimental impact on the pre-existing food chains

Anthropogenic Pressures

Ecosystem Loss

An ecosystem consists of the interactions between all living organisms (a community) and their abiotic environment (habitat)

• Ecosystems can become threatened by direct human activities (e.g. deforestation) or indirectly (e.g. climate change)
  

Example: Mixed Dipterocarp Forest

• Dipterocarps are a family of trees that function as a keystone species within the rainforest ecosystems of South East Asia
  

• Their presence provides an important habitat for native species in addition to providing nutritional support via fruits, pollen and nectar

• These forests are progressively being lost in order to provide timber and clear the land for agriculture (e.g. palm oil plantations)

• In Borneo, excessive deforestation is endangering native species like the orangutan, as well as threatening the water security and food sovereignty of the indigenous populations

Example: Great Barrier Reef

• Coral species form connected reefs that are greatly impacted by changes in oceanic temperature or pH
  

• Coral polyps receive nutrition from photosynthetic zooxanthellae (algae) that live within the polyp’s endodermis

• Changes in ocean temperature or pH may cause zooxanthellae to leave the coral tissue, leading to coral bleaching

• Anthropogenic greenhouse gas emissions are increasing oceanic temperatures and decreasing pH (ocean acidification)

• This has resulted in mass bleaching of the Great Barrier Reef off the coast of Australia, threatening the indigenous marine ecosystem