Download Subtropical deserts are characterized by their dry

Subtropical deserts are characterized by their dry environments, while
chaparrals are characterized by the presence of shrubs.
LEARNING OBJECTIVE [ edit ]
Recognize the distinguishing characteristics of subtropical deserts and chaparrals
KEY POINTS [ edit ]
Subtropical deserts are centered on the Tropics of Cancer and Capricorn.
Subtropical deserts can be hot or cold, but they are all very dry,having very
low annual precipitation.
Because precipitation is so low in subtropical deserts, most plants are annuals which
utilize adaptations to conserve water.
Chaparrals (scrub forests) are found in California, along the Mediterranean Sea, and along the
southern coast of Australia.
Chaparrals are very wet in the winter, but very dry in the summer months; most chaparral plants
stay dormant during the summer.
Most chaparral plants are shrubs adapted to fires; some seedsonly germinate after a fire.
TERMS [ edit ]
chaparral
a region of shrubs, typically dry in the summer and rainy in the winter
subtropical desert
dry region centered on the Tropics of Cancer and Capricorn where evaporation exceeds
precipitation
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Subtropical Deserts
Subtropical deserts, which exist between 15° and 30° north and south latitude, are centered
on the Tropics of Cancer and Capricorn. In some years, evaporation exceeds precipitation in
this very dry biome. Subtropical hot deserts may have daytime soil surface temperatures
above 60°C (140°F) and nighttime temperatures approaching 0°C (32°F). In cold deserts,
temperatures may be as high as 25°C (77°F) and may drop below -30°C (-22°F). Subtropical
deserts are characterized by low annual precipitation of fewer than 30 cm (12 in), with little
monthly variation and lack of predictability in rainfall. In some cases, the annual rainfall can
be as low as 2 cm (0.8 in), such as in central Australia ("the Outback") and northern Africa.
Types of Deserts
There are several types of deserts including high-pressure deserts, mid-continent deserts,
rain-shadow deserts, andupwelling deserts. In high-pressure deserts, the highatmospheric
pressure enables the air to retain more moisture and there is little rainfall. High-pressure
deserts include the Sahara, Arabian, Thar, and Kalahari deserts, and the desert regions
within the Arctic and Antarctic circles. Areas in the middle of a continent can receive little
rainfall because moisture tends to condense before it reaches the middle of a large continent.
Modern examples of mid-continent deserts are the Turkmenistan, Gobi, and Great Australian
deserts. Third, rain-shadow deserts are created when moisture from the ocean condenses on
one side of a mountain range. These mountain ranges usually have a rainforest on one side
and a desert on the other. Examples of rain-shadow deserts include the Mojave desert in the
rain-shadow of the Sierra Nevada, the Patagonian desert in the rain-shadow of the Andes,
and the Iranian desert in the rain-shadow of the Zagros mountains. Finally, upwelling deserts
exist adjacent to areas where cold currents rise to the ocean surface, reducing evaporation.
Examples include the Atacama desert, the Western Sahara, and the Namib desert.
Adaptations for Deserts
The type of vegetation and limited animal diversity of this biome are closely related to the low
and unpredictable precipitation. Very dry deserts lack perennial vegetation that lives from
one year to the next. Instead, many plants are annuals that grow quickly, reproduce when
rainfall does occur, and then die. Many other plants in these areas are characterized by
having a number of adaptations that conserve water, such as deep roots, reduced foliage, and
water-storing stems . Seedplants in the desert produce seeds that can remain in dormancy for
extended periods between rains. To reduce water loss and conserve energy, many desert
animals like the fennec fox are nocturnal and burrow during the day .
Fennec fox
Fennec foxes live in the deserts of Northern Africa and have large ears for heat dissipation during the
day. They stay in burrows during the day and are mostly active at night.
Desert plants
To reduce water loss, many desert plants have tiny leaves or no leaves at all. The leaves of ocotillo
(Fouquieria splendens), shown here in the Sonora Desert near Gila Bend, Arizona, appear only after
rainfall and then are shed.
Chaparral
The chaparral, also called the scrub forest, is found in California, along the Mediterranean
Sea, and along the southern coast of Australia . The annual rainfall in this biome ranges from
65 cm to 75 cm (25.6–29.5 in), with the majority of rain falling in the winter. Due to the very
dry summers, many chaparral plants are dormant during that season. The chaparral
vegetation is dominated by shrubs and is adapted to periodic fires, with some plants
producing seeds that only germinateafter a hot fire . The ashes left behind after a fire are rich
innutrients, such as nitrogen, that fertilize the soil and promote plant regrowth.
Chaparrals
The chaparral, or scrub forest, is dominated by shrubs adapted to periodic fires. Some plants produce
seeds that only germinate after a hot fire.