Ecosystems

• Ecosystems are found in different parts of the world and have different characteristics. Climate and local factors each play a part in where ecosystems occur.
• Climate


  The Earth's climate depends on energy from the Sun. It affects growing conditions for vegetation, and affects the location and characteristics of large-scale ecosystems.
• Temperature


  • Temperatures are lower at higher latitudes, so boreal forests are much colder than tropical rainforests. Growing seasons are longer in warmer locations.
• Precipitation


  • The global circulation system influences precipitation. Desert areas have low precipitation due to descending dry air.
• Sunshine hours


  • Lower sunshine hours in tundra ecosystems mean much less sunlight for plants to carry out photosynthesis than in tropical rainforests.
• The world's tropical forests are mainly found in a band stretching west to east just north and south of the Equator, between 23.5°N and S.
• Temperate forests


  • Have high rainfall and there are seasonal variations in the Sun's rays. Trees lose their leaves in the cool winters.
• Tundra


  • The Sun gives little heat here and there is little rainfall. Only tough, short grasses survive.
• Deserts


  • Are close to the Tropics of Cancer and Capricorn. This is where hot dry air sinks down to the Earth's surface and the Sun's rays are concentrated, making it very hot in the day.
• Tropical rainforests


  • Are mostly found either side of the Equator. The temperature is hot and there is heavy rainfall.
• Rock and soil type differences can lead to different vegetation in the same ecosystem. Altitude differences can lead to different plants growing within the same ecosystem.
• The biosphere is important for providing resources for people (food, medicine, building materials and fuel resources) but the biosphere is being increasingly exploited.
• Resources from the biosphere

  • Food (natural vegetation, crops, fish, meat, animal dung)
  • Medicine (poppies, aloe plant, lichens)
  • Building materials (straw, timber, bricks)
  • Fuel (fermenting crops, animal dung)
• Increased water demand (urbanisation, agriculture and industry) means there is less water in the biosphere for other areas, e.g. wetlands.
• Production of biofuels means that fewer food crops can be grown for local people.
• The UK has its own range of varied and important ecosystems - moorlands, heaths, woodlands and wetlands, as well as marine ecosystems.
• Terrestrial ecosystems in the UK

  • Moorlands
  • Heathlands
  • Woodlands
  • Wetlands
• Marine ecosystems in the UK

  • Important for tourism, energy (wind farms), and fishing
• Humans can damage marine ecosystems through development of coastlines, climate change, overfishing, and fertiliser runoff leading to eutrophication.
• The tropical rainforest is a very productive ecosystem with biotic components (living parts) and abiotic components (non-living parts).
• Tropical rainforest soils


  • Low in nutrients due to leaching, chemical weathering is common but nutrients are not available for plant growth
• Nutrient recycling in tropical rainforests

  Nutrients are transferred between three key stores: biomass, litter and soil
• The tropical rainforest is the most productive large-scale ecosystem on Earth, with high biodiversity and productivity.
• Animal adaptations in the tropical rainforest

  • Monkeys have evolved strong gripping hands and feet and long tails for balance, many species are camouflaged
• Plant adaptations in the tropical rainforest

  • Emergent trees grow up to 40m to reach above the canopy, trees are deciduous, lianas climb tree trunks, leaves have thick waxy coatings and drip-tips, roots are shallow with buttress roots for stability
• Tropical rainforests provide a range of goods (food, medicines, timber) and services (carbon storage, tourism, revenue) but are under threat from climate change.
• The main reasons for clearing tropical rainforests are resource extraction, conversion to agriculture, and population pressure.
• 7.3 million hectares of rainforest are cleared each year: the equivalent of 36 football pitches of forest every minute.
• Tropical rainforest management involves policies and strategies to protect and sustainably use these ecosystems.
• 36 football pitches of rainforest are cleared each minute
• Tropical rainforests are being cleared to make room for cattle ranching because of increasing demands for beef
• Other agricultural uses include large-scale oil palm plantations
• There is a high demand for palm oil as it is used in food products and cosmetics, and as biofuel
• Farmers can make a lot of money by clearing forest and planting oil palm plantations
• Indonesia's oil palm plantations cover 9 million hectares; 26 million hectares are projected for 2025
• Resource extraction is causing the deforestation of tropical rainforests
• The Amazon rainforest is an important ecosystem that needs sustainable management
• The Amazon rainforest consists of one-third of the planet's remaining tropical rainforest
• The Amazon rainforest provides resources for people locally and worldwide, including food, water, timber and medicines
• The Amazon rainforest is home to a diverse range of plants and animals, with over 1300 bird and 40000 plant species