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for Plants and Animals in Deserts
population is increasing at an alarming rate. Herds of cattle, sheep and goats as
well as people gathering firewood strip vegetation. Once this cover is lost,
the ground may easily be eroded by wind and rain, and the desert gains a few
margins have been advancing with disastrous effects on local plants and animals,
especially in Africa. This process of desertification is complicated, but it
occurs largely in many countries.
The problems for plants in deserts is
first to find water and then keep it. Some plants take up the dew which forms
in coastal desert areas. Some such as acacia, develop extremely long tap roots
to reach deep ground water supplies others, like cacti have root systems which
are shallow but extensive so that they can get the maximum amount from
occasional floods. Cacti also exhibit other characteristic of desert plants.
They are succulents which store water and they have thick waxy skins to prevent
transpiration. Some grasses have rolled up leaves so that transpiring surfaces
are inside. Desert trees shed their leaves before the dry season.
deserts must avoid overheating and water loss. Many adopt a nocturnal habit to
shun daytime heat. Some burrow into the ground. Insets tend to be poorly suited
to desert conditions. However, reptiles can survive reasonably well.
Controlling their temperature by moving from sun to shade, large animals such
as camels seen shade in the hottest part of the day and get their water from
food rather than by drinking.