2.5 - Hot Desert Case Study: Namib Desert, Namibia (Paper 1)

Question 1

Explain the examples of adaptations of plants in the Namib Desert: (3)

Answer 1

• Camel Thorn Tree: Has a strong tap root which can grow up to 60 metres allowing it to absorb water from deep underground. (1)
• Nara plant: This plant is found mainly in the Namib Desert and has been in existance for 1000 years. The reason it has survived for so long is because this plant has spikes instead of leaves to reduce water loss and it absorbs water droplets from fog through its steams. The bottom of the plant dies off as it is covered with sand, this provides nutrients for the new growth. (1)
• Quiver Tree: There are over 250 species of quiver trees in the Namib Desert. These are succulents, they can store water in their trunks and branches due to the spongy fibre. Their leaves also store water and have a smooth waxy surface to reduce water loss. The yellowish bark helps to reflect the suns heat. (1)

Question 2

Explain examples of adaptations of animals in the Namib Desert: (3)

Answer 2

• Fog basking beetle: These beetles are 2x greater in size than a normal beetle. It gathers water by standing on its head in a morning while the water vapour from the fog condenses on its back and trickles down to its mouth. (1)
• Desert Elephant: Only 350 of these are living in the Namib Desert. These elephants have smaller bodies, broader feet and longer legs than other elephants. The broader feet help to spread their weight on the sand and the smaller body. (1)
• Golden Mole: These were first discovered in the Namib Desert 250 years ago. With powerful digging claws, dense fur which repels dirt so they can almost swim through the sand. With very efficient kidneys, they do not need to drink much water at all. (1)

Question 3

Explain the characteristics of the Namib Desert: (6)

Answer 3

• Soil type: Soilless. (1)
• The highest day time temperatures can reach over 45 degrees celcious. (1)
• Night time temperatures can be as low as 0 degrees celcious. (1)
• The areas nearest to the coast are cooler due to the effect of a cold ocean current - the Bengula Current. (1)
• The cooling effect of the ocean can also lead to the formation of fog which can affect the coastal areas more than thalf the year. (1)
• Annual precipitation varies between 2-200mm per year. (1)

Question 4

Explain the threats to the Namib Desert: (3)

Answer 4

• Increased tourism to the Namib desert has led to activities such as off-roading and sand boarding. This is a threat because the soil in the Namib desert takes over 2000 years to be recovered from being driven over, this leads to small lichens and plants in the sand being destroyed and this effects the food web. (1)
• Mining for diamonds, uranium, copper and zinc occur in the Namib Desert at the Uranium mine near Swakompund. As a result of this 19km2 of plant and animal habitat is destroyed due to the removal of large areas of sand to enable mining. This results in a loss of biodiversity and increase in soil, water and air pollution. (1)
• Each year nearly 100 rhinos are illegally poached. The illegal poaching of animals impacts the food web. As well as this, it can lead to species endangerment and in the worst case, it can lead to extinction of a certain species. (1)

Question 5

Explain why the amount of rainfall is so low in the Namib Desert: (3)

Answer 5

• The Bengula current is a cold ocean current which travels northwards along the west coast of Southern Africa. Because the current is cold, it cools the air above it which increases its density. This leads to a high pressure system forming which leads to the amount of rainfall being low. (1)
• There is only 2000km2 worth of water sources in the Namib Desert which only accounts for 2% of the entire land area of the Namib Desert. Because there is a lack of water sources, this means that there is a lack of water to evaporate and form clouds. This leads to a low amount of rainfall. (1)
• The Namib Desert stretches 162km inland from the coast. Because most of the desert is located inland and a small proportion lies on the coast, there is less moisture and evaporation further inland which is why rainfall is low in the Namib Desert. (1)