Hot arid and semi-arid environments
1. For an area of semi-arid or arid climatic conditions, explain the causes of
desertification, and evaluate to what extent sustainable management
techniques have been effective. [20]
● The Eastern Cape province of South Africa receives 350 - 550 mm rainfall per
annum, classifying the area as semi-arid
● The thicket vegetation of the EC has been recognised as being particularly
vulnerable to degradation, mainly due to years of overgrazing
● Over 95% of this vegetation is under threat from overgrazing by domestic stock; bush
clearing; coastal resort development; and invasion by alien vegetation.
Intro:
● Definition of semi-arid, arid, desertification
● Sustainability meaning: a) the intrinsic values of the environment are respected in the
way natural resource use is conducted; b) the role of ecosystem services in
supporting human well-being is respected; and c) all role players ensure that
economic benefits are derived from the income of nature’s capital and not the capital
per se.
P1 explanation causes of desertification:
● Intensive grazing/overgrazing
- Wind and water erosion and salinisation
● Pastoralism with domestic herbivores
● 4-5 year drought from 2015 to early 2020 due to poor water management and
unpredictable rainfall patterns
P2 effective sustainable management:
● Drought-resistant fodder crops: american aloe, prickly pear, saltbrush and the
indigenous gwanish.
● The American aloe can be used for fencing, for kraals, for soil conservation and as
fodder.
- It requires little moisture
- It’s not attacked by any insects
- Raises milk production in cows
- Can act as a windbreak
- The juice is used in producing tequila
● Goats thrive on saltbrush, it needs less than half the water needed by other crops
and requires no irrigation once established. It remains green throughout the year and
so can provide all-year fodder.
P3 not effective:
● Insufficient access to land, poor infrastructure and a lack of education and finance
are still problems
● Drought- resistant fodder such as saltbrush is difficult to propagate and needs high-
quality management
● Precipitation trends have continued to exert a high degree of inter-annual variability
for the Eastern Cape which means the possibility of droughts remains high
, ●
Essential oils
● There are currently 10 government funded essential oils farms
● Common plants in S. Africa: eucalyptus, citrus, buchu, geranium and rosemary
- Rosemary grows well in drier conditions
● These plants replace goats/cows in terms of revenue and so allow the land to be
regenerated instead of degenerated
● Once the oil is extracted from the crop the remaining waste is used as a natural
fertiliser
● Essential oils can bring huge profits - 300 times more effective than goat farming as
6000 hectares of goats produce the same revenue as 20 hectares of rosemary oil
● The essential oil crops may eventually ruin the soil by removing all the nutrients
Game farming
● Shift from pastoralism to game farming - 2.5% of the Eastern Cape farms have
converted entirely from stock to game farming
- In a survey, 41 different game species including kudu and bushbuck were
found on the 63 game farms surveyed
● The hooves of game farm animals are shaped in such a way that there is less of an
impact on the ground, as they have pointier hooves than goats/cows
● They eat less and are more adapted to drought/aridity, meaning they are more likely
to survive during droughts such as the 2015-2020 one
● The introduction of extralimital species (for tourism) may threaten the sustainability of
game farming
- These species could become invasive or out-compete native species
● Hybridisation threatens the ecosystem as some farmers kept different species such
as the Blesbok and Bontebok antelope in the same fenced area
● The game farming industry is troubled by the inconsistent application of regulations
since there is no single national permit system
2. Evaluate the importance of the role of Pleistocene pluvials in the development
of desert landforms. [20]
● During the Pleistocene Ice Age 30% of the world’s surface at higher latitudes
contained ice
- At lower latitudes increased rainfall was experienced during pluvial periods
● Pluvial - a modern climate characterised by relatively high precipitation/ a period of
time of variable length, during which a climate is characterised by relatively high
precipitation or humidity
● As climatic conditions changed the landforms formed by water were left dried out
Evidence:
● Dry salty basins are evidence that water levels were higher in the past
● Living organisms have left traces of their existence in ancient lakes: pollen, siliceous
protozoans, biogenic silica, diatoms and algal pigments
● Lake Chad may have been 120m deeper than it currently is and may have extended
hundreds of kilometres north of its current location
● Spring deposits of lime (tufa) were formed by the precipitation of carbonate minerals
from ambient temperature water bodies
1. For an area of semi-arid or arid climatic conditions, explain the causes of
desertification, and evaluate to what extent sustainable management
techniques have been effective. [20]
● The Eastern Cape province of South Africa receives 350 - 550 mm rainfall per
annum, classifying the area as semi-arid
● The thicket vegetation of the EC has been recognised as being particularly
vulnerable to degradation, mainly due to years of overgrazing
● Over 95% of this vegetation is under threat from overgrazing by domestic stock; bush
clearing; coastal resort development; and invasion by alien vegetation.
Intro:
● Definition of semi-arid, arid, desertification
● Sustainability meaning: a) the intrinsic values of the environment are respected in the
way natural resource use is conducted; b) the role of ecosystem services in
supporting human well-being is respected; and c) all role players ensure that
economic benefits are derived from the income of nature’s capital and not the capital
per se.
P1 explanation causes of desertification:
● Intensive grazing/overgrazing
- Wind and water erosion and salinisation
● Pastoralism with domestic herbivores
● 4-5 year drought from 2015 to early 2020 due to poor water management and
unpredictable rainfall patterns
P2 effective sustainable management:
● Drought-resistant fodder crops: american aloe, prickly pear, saltbrush and the
indigenous gwanish.
● The American aloe can be used for fencing, for kraals, for soil conservation and as
fodder.
- It requires little moisture
- It’s not attacked by any insects
- Raises milk production in cows
- Can act as a windbreak
- The juice is used in producing tequila
● Goats thrive on saltbrush, it needs less than half the water needed by other crops
and requires no irrigation once established. It remains green throughout the year and
so can provide all-year fodder.
P3 not effective:
● Insufficient access to land, poor infrastructure and a lack of education and finance
are still problems
● Drought- resistant fodder such as saltbrush is difficult to propagate and needs high-
quality management
● Precipitation trends have continued to exert a high degree of inter-annual variability
for the Eastern Cape which means the possibility of droughts remains high
, ●
Essential oils
● There are currently 10 government funded essential oils farms
● Common plants in S. Africa: eucalyptus, citrus, buchu, geranium and rosemary
- Rosemary grows well in drier conditions
● These plants replace goats/cows in terms of revenue and so allow the land to be
regenerated instead of degenerated
● Once the oil is extracted from the crop the remaining waste is used as a natural
fertiliser
● Essential oils can bring huge profits - 300 times more effective than goat farming as
6000 hectares of goats produce the same revenue as 20 hectares of rosemary oil
● The essential oil crops may eventually ruin the soil by removing all the nutrients
Game farming
● Shift from pastoralism to game farming - 2.5% of the Eastern Cape farms have
converted entirely from stock to game farming
- In a survey, 41 different game species including kudu and bushbuck were
found on the 63 game farms surveyed
● The hooves of game farm animals are shaped in such a way that there is less of an
impact on the ground, as they have pointier hooves than goats/cows
● They eat less and are more adapted to drought/aridity, meaning they are more likely
to survive during droughts such as the 2015-2020 one
● The introduction of extralimital species (for tourism) may threaten the sustainability of
game farming
- These species could become invasive or out-compete native species
● Hybridisation threatens the ecosystem as some farmers kept different species such
as the Blesbok and Bontebok antelope in the same fenced area
● The game farming industry is troubled by the inconsistent application of regulations
since there is no single national permit system
2. Evaluate the importance of the role of Pleistocene pluvials in the development
of desert landforms. [20]
● During the Pleistocene Ice Age 30% of the world’s surface at higher latitudes
contained ice
- At lower latitudes increased rainfall was experienced during pluvial periods
● Pluvial - a modern climate characterised by relatively high precipitation/ a period of
time of variable length, during which a climate is characterised by relatively high
precipitation or humidity
● As climatic conditions changed the landforms formed by water were left dried out
Evidence:
● Dry salty basins are evidence that water levels were higher in the past
● Living organisms have left traces of their existence in ancient lakes: pollen, siliceous
protozoans, biogenic silica, diatoms and algal pigments
● Lake Chad may have been 120m deeper than it currently is and may have extended
hundreds of kilometres north of its current location
● Spring deposits of lime (tufa) were formed by the precipitation of carbonate minerals
from ambient temperature water bodies
