Land Cover Change (SACE Stage 2 Geography Environmental Change)

What this dot point is asking

This dot point sits inside Topic 1, Environmental Change. You are expected to read land cover data from satellite imagery and maps, explain why change happens, and judge how well it is being managed. Strong answers separate land cover (what physically covers the ground) from land use (how people use that land), then connect the two.

Distinguishing land cover from land use

Land cover is measured by remote sensing: satellites such as Landsat record reflected light to classify the surface as forest, crop, water or urban. Land use is the human purpose, for example grazing, mining or housing. A paddock and a national park can share the same grassland cover but have very different uses. SACE rewards students who use this distinction and who quote land cover statistics drawn from satellite or census data.

Causes of land cover change

The dominant driver is human demand for food, fibre, fuel and space, amplified by population and economic growth.

• Deforestation and clearing: Australia is the only developed country on global deforestation fronts. Queensland has cleared hundreds of thousands of hectares of native vegetation in some recent years, largely for pasture, fragmenting habitat in the Brigalow Belt.
• Agricultural expansion: globally, agriculture occupies roughly half of all habitable land. In the Amazon, cattle ranching and soy drive the largest tropical forest loss on the planet.
• Urban expansion: cities such as Melbourne and Sydney spread outward, converting farmland and bushland on the fringe into housing and roads.
• Land degradation and desertification: in the Sahel, drought, overgrazing and firewood collection convert dryland into bare, eroded surfaces.

Consequences across the three systems

SACE marks answers that trace consequences through environmental, social and economic systems.

Environmentally, removing forest cover reduces carbon storage, raises local temperatures, increases soil erosion and silts up rivers. Clearing in catchments feeding the Great Barrier Reef sends sediment and nutrients onto the reef, worsening its decline. Loss of vegetation also reduces biodiversity and can change rainfall patterns.

Socially, land cover change can displace communities and damage the connection of Aboriginal and Torres Strait Islander peoples to Country. Urban sprawl increases commuting times and reduces access to green space, while desertification in the Sahel drives food insecurity and migration.

Economically, change can bring short-term gains (timber, crops, housing) but long-term costs through lost soil productivity, flooding and the price of restoration. Land degradation is estimated to cost the global economy trillions of dollars in lost ecosystem services each year.

Strategies for managing land cover change

Management works at several scales. Internationally, the UN Convention to Combat Desertification and the goal of land degradation neutrality aim to balance new degradation with restoration. National policy includes vegetation management laws that regulate clearing, although enforcement and political change affect how well they work.

Local strategies include revegetation and shelterbelts, no-till farming to hold soil, urban growth boundaries to limit sprawl, and Indigenous land management such as savanna fire programs in northern Australia that reduce destructive late-season fires. Restoration projects such as China's Loess Plateau rehabilitation show that degraded land can be returned to productive vegetated cover at large scale.

Linking it together

A complete response uses the land cover versus land use distinction, reads spatial patterns from satellite or map data, explains both natural and human causes, follows consequences through environmental, social and economic systems, and evaluates management at more than one scale using cases such as Queensland clearing, the Amazon and the Sahel. That structure matches the geographical skills and applications criteria the SACE Board assesses.