human impact

• Leading causes of habitat destruction

  • Agriculture
  • Logging
  • Mining for materials
  • Trawling
  • Urban sprawl and land conversion
  • Natural disasters
  • Over exploitation
  • Pollution
• Habitat fragmentation

  Parts of a habitat are destroyed, leaving behind smaller unconnected areas surrounded by an inhospitable matrix
• Habitat fragmentation

  • Leaves smaller habitable fragments with large more hostile edges
  • Leads to changes in community structure and increased interspecific and intraspecific competition within the fragment
  • Edge is subject to fluctuating temperature, wind speeds and light levels
  • Disturbance of species within the habitable fragments and increased inbreeding
  • Negative effects on species with large home ranges
  • Species that can't move across the matrix can become isolated and extinction results
• Mitigation measures for habitat destruction

  • Replanting of trees
  • Alternative habitat creation
  • Bridges and underpasses across roads: wildlife crossings
  • Creation of wildlife corridors
  • Land acquisition
  • Buffer zones
• Tropical rainforests

  • Considered the 'cradles of biodiversity' covering approx. 6% of the Earth's land surface, but home to over 50% of global biodiversity
  • Considered the 'lungs of the planet', taking in large quantities of carbon dioxide and releasing large quantities of oxygen
  • Act as carbon sinks - cutting and burning their biomass contributes to global climate change
  • Sources of many modern medicines, including quinine
  • The original source of food, including bananas, mangos, chocolate, coffee, and sugar cane
• Reasons for clearing the Amazon rainforest

  • Population growth and poverty encourage poor farmers to clear new areas
  • Mining
  • Roads and infrastructure that makes it easier for farmers to access areas
  • Timber harvesting for domestic use or export
  • Cattle pasture
  • Industrial agriculture for palm oil, plantation of bananas, pineapples, and sugar cane
• Palm oil

  Includes biscuits, bread, crisps, and chocolate. The main cooking oil in Indonesia and Myanmar. Used in cosmetics and toiletries e.g. soaps, shampoos, detergents, and toothpaste. Increasingly used as a biofuel
• Urbanisation

  The process of people moving from rural to urban areas, resulting in the growth of cities
• Effects of urbanisation

  • Loss of greenspace- limited mainly to fragmented habitats: gardens, parks and churchyards
  • Loss of habitats and habitat fragmentation
  • Increased non-native species e.g. rats, exotic pets and plant species
  • Highly mobile rapidly growing plant and animal species tend to flourish
  • More urban adapted generalist species
  • Urban exploiters
• Species moving into cities can threaten human populations and spread zoonotic disease e.g. Leptospirosis, Lymes disease, Covid 19, toxoplasmosis
• Hidden effects of urbanisation for biodiversity include light and sound pollution, and increased food availability
• Sustainable/green city

  A city designed with consideration for social, economic, environmental impact, and resilient habitat for existing populations, without compromising the ability of future generations to experience the same
• Hidden costs of mining include infrastructure, dealing with waste, noise pollution, habitat destruction. Coal mining will increase global warming when fuel is burnt. Lithium mining gives problem of disposal of lithium. Mining will give a supply until 2030 at the latest. Coal produced would be used to make steel
• Wind turbines can affect fauna in both positive and negative ways. Placed in migration pathways can decimate bird populations and can also impact bats. Interconnection cables can allow countries to share electricity generated, meaning that low wind speeds doesn't have a large impact
• Construction of solar panels creates a large carbon footprint, but this is lost when panels are working. Producing solar panels is more costly than most other sources of renewable energy. Disadvantage - they only work during the day, so supply is inconsistent and they need large areas for installation as they are quite inefficient (15%)