The Desert
Rainfall And Climate
There are three types of deserts:
tropical, temperate, and polar. Tropical
deserts are generally hot and dry and
relatively barren like Saudi Arabia.
Temperate deserts are hot in the summer and
cold in the winter and have the most rainfall
of any type of desert. These are found in
places like Reno, Nevada and have sparse
vegetation like cactuses. Polar, or cold
deserts are found in places like northwestern
China and have low precipitation. The
semiarid zones between deserts and
grasslands are called semideserts and have
more vegetation than others.
Deserts Plants
Desert plants adapt to the hot, dry climate of a desert in many ways. The mesquite and
creosote for example drop their leaves and survive in a dormant state during prolonged droughts.
Saguaro have no leaves to limit evaporation and they store water in their fleshy tissue as well as
only opening up to absorb carbon dioxide at night to preserve their
water as much as possible. Plants like the prickly pear cactus use
deep roots to reach groundwater.
-Mesquite
-Saguaro
-Prickly Pear Cactus (pictured –>)
-Agave
-Yucca
Desert Animals
Some small animals like the kangaroo rat survive desert heat by burrowing in cool, rocky
crevices, others have physically adapted. Insects and lizards like the collared lizard have thick
outer coverings to retain moisture. Insects like the Arabian oryxes find water in dew rather than
depending on bodies of water.
-Kangaroo Rat (pictured –>)
-Diamondback Rattlesnake
-Jack Rabbit
-Collared Lizard
-Arabian Oryx
Limiting Factors
The primary abiotic factors that limit life in the desert are the harsh climate which
includes both extremely high and low temperatures as well as minimal rainfall and often long
droughts. Because there is so little moisture in the soil the temperatures at night and day are
drastically different because there is no water to regulate the change. These problems lead to
limiting biotic factors for many
organisms such as a lack of food due
to the sparse vegetation. All of these
factors combine lead to a relatively
low carrying capacity which means
that fewer organisms of any given
species can survive in the desert than
in more lush biomes.
Species Interaction
Cooperation and competition
among desert organisms is vital to
many plants and animals survival. The guinea worm is a parasite which
latches onto animals and survives off of them when they drink. With
such limited supplies of food and water there is a great deal of
competition for resources. For example both the collared lizard and the
roadrunner eat the darkling beetle so they must compete for this finite
resource. This is why bio-diversity is so vital to the survival of an
ecosystem because without a variety of organisms the overlaps in resources would cause
competition to drive species to extinction.
Desert Food Web–>
Major Environmental Issues
The desert is an arid environment with dry soil that contains very little moisture. Because
of the minimal water many plants reproduce infrequently and animals become dormant during
droughts, this means that any damage caused by humans takes longer to recover from. When
vegetation is depleted by livestock in a desert environment it may take decades for it to grow
back. Some of the major ways that humans are degrading deserts include land disturbance and
pollution from mineral mining, a depletion of already limited water supplies (such as in
southwestern California), and soil destruction by urban development. These disturbances destroy
the delicate balance of life that naturally exists.