Land cover change Flashcards
Environment
Environment means the living and non-living elements of the Earth’s surface and atmosphere. It includes human changes to the Earth’s surface.
The UN found that 75% of Earth’s terrestrial surface has been altered by human activity.
Natural biome
Natural biomes are those which have not had sustained, direct human interactions.
E.g. aquatic, desert, forest, grassland, and tundra
Anthropogenic biome
Anthropogenic biomes are biomes that are the result of sustained direct human interactions with ecosystems.
E.g. urban, rural or villages, croplands, and rangelands
Land cover change
Land cover change refers to the changes that have taken place in natural environments due to a variety of natural and/or human induced causes.
Ecosystem structure
The ecosystem has a structure made up of the biotic and abiotic elements, with a hierarchy of organisms which includes, producers, consumers, and detritus.
Ecosystem dynamics
The ecosystem is dynamic, meaning there are relationships between biotic and abiotic elements, which includes the flow of energy between the elements (food chains and food webs). There is also an exchange of matter between biotic and abiotic elements within the system (nutrient cycle).
Biodiversity loss
The extinction of species (plant or animal) worldwide, and also the local reduction or loss of species
in a certain habitat.
Climate change
Climate change is a long term change in the statistical distribution of weather patterns over periods of time that range from decades to millions of years.
E.g. greater or fewer extreme weather events
Sustainability
Meeting the needs of current and future generations through simultaneous environmental, social
and economic adaptation and improvement.
E.g. adapting power generation strategies to ensure protection of the environment while mainting a benefit to people in terms of economic growth and standard of living.
Identify the processes of land cover change.
- Deforestation
- The expansion and intensification of agriculture
- The growth of urban settlement
- Mining
Deforestation
The removal or clearing of forests generally for other uses, such as agriculture and urban development.
- Clear cutting - removal of all the trees in an area of forest.
- Slash and burn - forests are cut down and vegetation is burned to create a field.
Deforestation example: Borneo
Third largest island in the world located in Asia. Dense rainforests and mangroves ➡ industrial palm oil and timber plantation. Palm oil is highly profitable, double income for farmers. Illegal plantations. Responsible for 40% of deforestation since 2000.
The expansion and intensification of agriculture
The expansion of agriculture refers to the increasing amount of land available for agriculture. The intensification of agriculture refers to an increase in the output from existing agricultural areas. ⬅ efficient methods of farming (fertilisers, technology)
- Over a third of the world’s terrestrial land and 75% of freshwater resources dedicated to crop or livestock production.
- Globally 20% more land converted to agriculture by 2050.
- 300% increase in food crop production since 1970.
The expansion and intensification of agriculture example: The Green Revolution
Key turning point in global agricultural production in mid-20th century. Adopted new technology:
- Chemical - pesticides and fertilisers
- Mechanical - tractors and improved irrigation
Brazil ≈ 500% increase in cereal output since 1960. Expanded area used for agriculture by ≈ 90%.
The growth of urban settlement
Clearing of native vegetation, fragmentation of habitats, building of infrastructure required to support urban areas. Greatest influence on global environmental change due to total transformation.
Global urban land cover ≈ 1% to 3%.
The growth of urban settlement example: Lagos, Nigeria
One of the world’s fasted growing cities, experiencing both rapid urbanisation and urban growth, doubling in size since 1990. Growth was accompanied by loss of bare soil, vegetation, and water bodies.
Mining
Changes to abiotic and biotic conditions, with significant amounts of land being cleared, use and release of chemicals, dust, and aerosols during the mining process.
Mining example: Australia vs Peru
Mining represents a significant part of Australia’s economy, generating ≈ 60% of total export revenue in 2020. Highly regulated. Sediment movement from Madre de Dios in Peru has degraded many ecosystems along connecting rivers in Brazil.
Remote sensing
The science of obtaining information about objects or areas from a distance, typically from aircraft
or satellites.
Location, type, rate, and extent of land cover change
Remote sensing
- Location - examined at a range of scales, from local, regional, to global.
- Type - category of land cover change occuring (e.g. deforestation)
- Rate - speed at which changes have taken place (e.g. how much is being lost/altered annually)
- Extent - size and area of land cover change occuring (e.g. in km², %)
How remote sensing images identify and measure
- Cameras can remotely collect images to detect and monitor changes to physical characteristics.
- True colour, infrared/elevation image displays Earth’s colours in a way that allows changes to be easily identified.
- Infra-red can detect differences in surface temperatures.
- Laser technology can accurately create 3D topographic images of Earth’s surface.
E.g. Copernicus Sentinel 2 displays sediment near Great Barrier Reef lagoon after flooding in QLD in 2019. LIDAR is used to measure the presence of chemicals in the atmosphere and the heights of objects on the surface, including vegetation.
World population
- Humans are living longer.
- Majority of population growth is occuring in urban areas in developing countries.
- Fertility rates are declining.
E.g. global life expectancy is higher than any country in 1950. South Sudan has a population growth rate ≈ 5%.
Impacts of world population growth on land cover change
- Type - urban land use and land required for agriculture to feed the growing population.
- Rate/extent - urban areas have doubled since 1990 as a result.
Impacts of growing affluence on land cover change
- Type - demand for more resources including meat and dairy ➡ deforestation and expansion and intensification of agriculture.
- Rate - 300% increase in food crop production since 1970.
- Extent - Almost half of habitable land is used for food production.
Impacts of advances in technology on land cover change
Handsaws to chainsaws to large efficient forest machines have sped up the process of deforestation. Difficult and time consuming ➡ Cleared by a machine in the same time.
Government policy in Australia on land cover change
Strict in terms of rehabilitation of mine sites and other deforested areas. Land Use Agreement 2005 allows traditional custodians to transfer lease of land to mining operators while maintaining native title rights.
E.g. Argyle mine site, closed in 2020, produced 90% of the world’s pink diamonds. Mandated rehabilitation will take 5 years before land is returned to traditional custodians.
Government policy in Brazil on land cover change
Government encouraged economic growth by identifying the Amazon rainforest as a large area with significant potential for productivity.
- Built trans-Amazonian highway to allow easier access.
- Gave out free plots of land and paid citizens to farm.
E.g. 1980 to 1990 an average 20,000 km² of forest was cut down.
Changes in government policy in Brazil
Decrease in deforestation
Waves of protection of the Amazon.
- 80% decrease in deforestation between 2004 and 2014.
- Implementation of Forest Code ➡ 20% of farmland could be cleared, rest is set aside as native vegetation.
Changes in government policy in Brazil
Increase in deforestation
Deforestation increased by 20% in 2015 as a result of changes in government.
- Ruralistas (farmers and activists opposed to land reform) grew their hold of Brazilian parliament.
- Forest Code was weakened.
Culture and ideology in Australia on land cover change
Large scale agriculture and deforestation introduced with colonisation. Government policies show a shift in ideology.
- Greatly values its natural environment.
- Stakeholder groups such as World Wildlife Fund have an influence on the rate and scale of land cover change in Australia.
E.g. Urban sprawl and land clearing along the coast, with more than 85% of Australians living within 50km of the ocean. Expense of land cover change.
Changing culture and ideology in Brazil on land cover change
Government
Changing ideologies through shift in government priorities and more towards protection of Amazon. Simultaneously, government policies shifted to encourage cattle and soybean, continued emphasis on economic growth.
Culture and ideology in Brazil on land cover change
Stakeholders, farmers, migrants
Some areas considered environmentally progressive, prioritised sustainable use ⬅ pressure from stakeholders who see economic benefits. Farmers adapted methods of land clearing to avoid detection of policies. Clash of migrant land use with traditional land use.
Impact of Aboriginal and Torres Strait Islander peoples’ land management
Areas held or managed by indigenous peoples have less sever alteration of the environment. Globally, around 25% of land area is traditionally owned, managed, used/occupied by indigenous peoples.
Mosaic burning
Involved the use of cool burns (regular, relatively controlled, low intensity burns) to clear native vegetation. Patchwork burning system ➡ clear undergrowth ➡ reduced risk/severity of bushfires.
Many native plants require heat and/or smoke for germination such as the acacia.
Mosaic burning over time
Areas were changed or gradually transformed from dense forest/bush to more medium scrublands, it ensured that forests were not destroyed.
Seasonal calendars
Understanding the flowering of plants, hibernation of reptiles, when are where to hunt certain animals, leaving adequate seeds and vegetation to ensure regrowth of food source plants.
Ensured the sustainable use of the land, available for future seasons and generations, reducing the long term impact on land cover.
E.g. during Birak (December to January) land would be burned in mosaic patterns to increase grazing pastures, reduce fuel loads, and assist seed germination.
Impacts of land cover change
- Changes to the water cycle
- Soil erosion and degradation
- Loss of habitat and biodiversity
- Loss of ecosystem services
- Degradation of aquatic and marine environments
- Urban heat islands
Changes to the water cycle
Tree roots take mouisture from deep in the soil and release it through their leaves via transpiration ➡ rainfall. Irrigation depletes rivers and water tables, and nutrient runoff due to fertilisers can cause eutrophication.
Amazon is responsible for 10% of water recycled by Earth’s vegetation each day through transpiration.
Soil erosion and degradation
Soil erosion, soil compaction, loss of soil structure, nutrient degradation, and soil salinity.
- Reducing the quantity and quality of soil ➡ reduce productivity and economic value ➡ threatens food security.
In Australia around two thirds of all agricultural land is affected by degradation.
How has deforestation exacerbated land degradation and erosion?
Removal of ground cover removes roots which help to hold soil together ➡ topsoil is suscebtible to being washed away. Less fertile land as the nutrient rich topsoil is gone and increased levels of soil acidity due to fertilisers.
Loss of habitat and biodiversity
Expansion of agricultural lands, increase in demand for timber/forest products, overgrazing, changing climates. Habitat loss includes the thinning, fragmentation, or destruction of a habitat ➡ loss of biodiversity, endangerment and extinction, destruction of breeding grounds, ecological imbalance.
Australia has one of the highest rates of animal extinction in the world due to rapid rate of deforestation. Since colonisation, Australia has lost 26 mammals and put 1700 others in the endangered/threatened classifications.
Loss of habitat and biodiversity example: Carnaby’s Black Cockatoo
Large scale clearing for agriculture in Wheatbelt (where they are locally extinct in many parts) removed breeding habitat. Ongoing urban development in Swan Costal Plain reducing its feeding habitat.
1970 to 1990 disappeared from over a third of their former range. Entire population is believed to have halved.
Loss of habitat and biodiversity example: Koalas
Endangered across much of eastern Australia. Koala numbers have dropped dramatically in recent years, due to climate-driven weather events and land-clearing for agricultural and urban development.
Populations in Queensland and New South Wales decreased by 50% or more in the last two decades.
Loss of ecosystem services
Ecosystem services refer to the benefits people derive from an ecosystem such as food and water. Diversion of surface water, removal of vegetation, urban infrastructure ➡ Impermeable surface (rooftops, roads), runoff containing pollutants carried into water bodies/watershed areas.
WHO increase in quantity and diversity of pollutants reaching freshwater systems since 1970s. India, 80% of country’s rivers are polluted from urban domestic sewage ➡ stomach ailments, waterborne diseases.
The degradation of aquatic and marine environments: Eutrophication
Quality of watershed areas and runoff into oceans impacts aquatic and marine flora and fauna.
When excess nutrients (fertilisers) enter the water courses and cause an algal bloom ➡ reduces oxygen in the water and fish/marine and aquatic life dies. Fertiliser runoff in QSD ➡ coral bleaching and algal bloom in Great Barrier Reef.
Since 2019, two major algal blooms locally in Swan and Canning river ➡ unable to consume seafood. Cockburn Sound area lead to over 2000 fish deaths.
The degradation of aquatic and marine environments: Ocean acidification
Result of rise in carbon dioxide levels created from processes of land cover change. Ocean absorbs carbon dioxide ➡ pH levels decrease, water becomes more acidic, affects marine biology.
30% increase in acidity since Industrial Revolution. Marine organisms such as corals, clams, mussels have difficulty forming shells. Larval clownfish struggle to locate habitats ➡ food web at risk due to biodiversity loss.
Urban heat islands
Clearing of lands to accommodate growing urban areas ➡ warming of temperatures due to human-made environment. Infrastructure absorbing/re-emitting the sun’s heat. Greenery is also sparser. Asphalt roads and concrete car parks.
Reported that some suburbs in Perth can be six degrees hotter than surrounding areas. Intensified by other human activities that generate heat, such as transport and industry.
