Chapter 6 - 'Natural Processes Changing Land Cover' Flashcards
Describe the effects of decline in average temperature.
The cooler hence drier conditions expand desert and semi desert areas, as a result forests shrink.
The last glacial period peaked between…
Temperatures were…
Sea levels were…
17000 to 20000 years ago.
4C cooler.
125m lower.
The UN estimated that ‘x’ of the population are at risk from…
2 billion
Desertification.
List what geophysical changes result in land cover change.
Volcanic activity, earthquakes, landslides.
All due to plate movements.
Describe how Volcanoes affect the land cover.
Explain how lahars are formed and how they affect the environment.
Outflows of lava, ash and rock smother the existing land cover
Lahars are ash deposits combined with rainfall, they are essentially mudflows which can bury the surrounding land covers.
Explain how earthquakes affect land cover. Elaborate.
2 different things
Earthquakes can elevate or depress land masses, forming steep slopes. These steep slopes result in the reduced ability to support anything more than sparse vegetation.
Earthquakes can also alter the direction of flow of moving water bodies, depriving previously hydrated vegetation of regular or seasonal water supplies.
Describe the process of plant succession.
Pioneer plants which first colonise the land are eventually replaced by secondary plant species, which use the conditions created by the pioneer plants. Eventually as the secondary species grows larger and become more diverse, they take over.
Explain how fire affects land cover.
Fires promoted the development of grass over trees whilst also cleaned the ground of ground litter (leaves and branches).
Explain how pests affect land cover.
Pests such as locusts sweep entire areas of vegetation.
This results in the ground becoming open to winds and soil erosion, reducing any chance of plant succession.
List the natural processes which change land cover.
Climate change.
Geophysical processes.
Plant succession.
Fires and pests.
