The BIOSPHERE is the part of the Earth's surface where we find living things
Parts of the biosphere are ECOSYSTEMS
When the ecosystems are large enough we call them BIOMES (worldwide ecosystems).
BIOMASS is the mass of all living organisms in an ecosystem
Factors Affecting Biomes
- The world can be divided into 9 different biomes, each one with its' own type of vegetation and wildlife.
- The location and characteristics (things that make a biome what it is) are mainly influenced by climate - usually because climate affects the growth of plants.
- Temperature is the most important factor; it varies with seasons and the length of the growing season depends partly on temperature.
- Precipitation is also important. A forest ecosystem with a large BIOMASS needs lots of rain. Ideally the rain should be distributed throughout the year - not just over a couple of months.
- Sunshine hours determine the amount of light available for photosynthesis (a process of plants producing energy).
- Humidity controls rates of EVAPOTRANSPIRATION (how much water is lost back into the atmosphere from the leaves etc)
Factors Affecting Vegetation
- Sunlight: nearer the equator means that sunlight is more concentrated
- Temperature: nearer the equator means that heat is more concentrated
- Precipitation: low pressure zones have higher precipitation
- Soil fertility: some soil contains more minerals than others, encourages growth of ecosystems
- Altitude: 200m rise in altitude = 1C decrease in temperature
- Continentality: nearer the coast means greater wind chill factor. Water retains heat for longer so coastal regions are warmer in winter but cooler in summer.
- Climate change will have many impacts on the biosphere, including these:
- Habitats will become increasingly fragmented (broken up)
- Habitats will change due to rising temperatures, changing rainfall patterns and rising sea levels
- Extreme weather events such as storms, floods and droughts may become more common
- Species face extinction as they can't migrate to new habitats quickly enough
- Pests and diseases will thrive in rising temperatures
1 degree rise
10% of land species could be extinct. Disappearance of glaciers & mountain ecosystems leads to loss of alpine plants.
2 degree rise
15-40% of land species could be extinct. Oceans become more acidic as more freshwater is added, coral reefs destroyed by bleaching.
3 degree rise
20-50% of land species face extinction. Sea level rising causing flooding of mangroves. Drought in the Amazon kills the Rainforest.
- Deforestation causes:
- Less interception
- More surface run-off
- No roots to hold soil = siltation
- Less groundwater
- Reduced soil fertility
- Fewer resources for future generations
- Loss of wildlife habitats
- Why does deforestation occur?
- Cattle ranching: TNCs export meat to MEDCs
- Accommodation: to locate the growing Brazilian population
- Logging: to export wood to MEDCs for furniture
- Conversion to farmland: to cater for the growing population
- HEP: to generate more energy
What Degrades The Amazon Rainforest?
- Population Growth in Brazil has meant that more land is needed for farms and housing
- Mining projects such as the Grans carajas programme which brought iron mines
- Clearance for timber, especially mahogany and teak which are made into furniture
- Agriculture - huge area of forest have been cleared for commercial agriculture in particular for growing soya beans
- Hydroelectric dams along the Amazon's tributaries have flooded forest valleys
- New Roads-the construction of new roads such as the Trans-Amazon Highway leads to forest loss
What services does the biosphere provide?
- Maintains soil health (decomposition of waste)
- Regulates oxygen and carbon dioxide balance
- Reduces global warming
- Leisure activities: go ape
- Tourism: rainforests
- Employment: rangers, tourist guides
- Regulating the hydrological cycle (interception, storage etc.)
What goods does the biosphere provide?
- Foods from animals: meat, milk, eggs
- Foods from plants: cereals, vegetables, fruits, nuts
- Products from animals: leather, feathers, fur
- Products from plants: cotton, paper, gums, resins, oils
- Building materials: slate, granite
- Fossil fuels: oil, gas, coal
How The Biosphere Serves Us
Forests remove carbon dioxide from the atmosphere reducing global warming
Forests give out oxygen purifying the atmosphere
Protect watersheds from soil erosion and intercept precipitation preventing flash flooding
By trapping silt, forests keep water pure
Reefs and mangroves provide protection from coastal storms
Forests provide leaf litter which forms humus which makes the soil more fertile for crops
Providing habitats for wildlife/biodiversity
Rainforest and reefs are very biodiverse
Provide homes for a huge range of organisms including some very rare animals
Reefs and rainforests provide attractive scenery for tourism
Small-scale Management Strategies
- UK Biodiversity Action Plans
- Established in 1992
- Goal: To conserve and enhance biological diversity within the UK and contribute to the conservation of global diversity through all appropriate mechanisms.
- The involve local communities in small-scale schemes e.g. planting trees.This is similar to community forest, however on a much smaller scale
- They aim to use resources sustainably
Large-scale Management Strategies
- Operates in 147 countries
- Intergovermental treaty
- Established in 1971
- These areas support 30% of fish species
- Promote sustainable use of wetland areas
- Protect living organisms in the areas
- Can encourage tourism and increase house prices in the area
- Convention on International Trade in Endangered Species
- Established in 1963
- Operates in 175 countries
- 30,000 species of animals and plants are listed
- It protects animals from extinction e.g. leopards, panthers, giant pandas
- Community Forests
- UK scheme established in 1994
- 12 forests across the UK around cities e.g. Sherwood
- Aims to reduce effects of global warming, protect wildlife habitats and also provide leisure and employment opportunities
Sustainable Development Of The Rainforest
- Brazil needs it to develop so leaving the forest untapped is not an option.
- Uncontrolled and unchecked exploitation can cause irreversible damage so sustainable use of the forest is essential
Possible strategies include:
- Agro-forestry - growing trees and crops at the same time. This lets farmers take advantage of shelter from the canopy of trees. It prevents soil erosion and the crops benefit from the nutrients from the dead organic matter.
- Selective logging - trees are only felled when they reach a particular height. This allows young trees a guaranteed life span and the forest will regain full maturity after around 30-50 years.
- Education - ensuring those involved in exploitation and management of the forest understand the consequences behind their actions.
- Afforestation - the opposite of deforestation. If trees are cut down, they are replaced to maintain the canopy.
- Forest reserves - areas protected from exploitation.
- Monitoring - use of satellite technology and photography to check that any activities taking place are legal and follow guidelines for sustainability