Deserts are formed in the driest of environment. The temperature of deserts may vary from very hot as in hot deserts, to a very cold as in cold deserts.
The most important hot deserts of the world is the Sahara-Arabia-Gobi which extends from Africa to Central Asia. It has a highly irregular an insignificant rainfall and low humidity. Hot deserts also occurs in India such as Sindh-Rajasthan desert South America, North America and Australia, cold deserts occurs in Ladakh regions of Himalayas and Tibet.
Desert plants which are adapted to drought conditions through reduced leaf size and the dropping of leaves in any conditions both reducing loss via evapotranspiration. The roots of most desert plants remain well developed and occur in the top of the soil in order to take maximum possible advantage of any rainfall.
The animals present in the desert are reptiles, insects and rodents. All these animals have special morphological, physiological and etiological adaptations for desert. Some desert animals are newly adapted for high extremes of temperatures. In general large animals are very uncommon except male deer. Some desert plant close their petals at night while many plants blossom only at night. There are some insects which remain active during the day while some insects are active at night.
ADVERTISEMENTS:
Some reptiles and insects are well adapted for their survival in deserts and excrete dry matter, kangaroo, rat and pocket mouse are able to live without drinking water. They do so by extracting the moisture from the seed they eat. The camel and the desert birds (ostrich) have an occasional drink of water but can go for long periods of time using the water stored in the body. Most insects of the deserts are herbivores.
The species composition of desert ecosystem is much more varied and typical.
The biotic components of deserts ecosystem are summarized as under:
(1) Producers:
ADVERTISEMENTS:
These are shrubs, bushes and some grasses and a few trees. The shrubs have widespread, branched root system. Some lower plants like xerophytes mosses may also be present.
(2) Consumers:
The most common animals are reptiles and insects which are able to live under xeric conditions. These are also present some nocturnal rodents and birds. The camel feed on tender shoots of the plants.
(3) Decomposers:
ADVERTISEMENTS:
They are very few due to poor vegetation. The amount of dead organic matter is correspondingly less. There are also some fungi and bacteria most of which are hemophilic.