v Deserts are defined as areas with an average annual precipitation of less than 250 millimeters per year.
v It occupies about 17% of the earth’s surface.
v Deserts are characterized by hot days & cold nights.
v The deserts of the world are mainly located in the
South- western United States, Mexico, North
America, Asia (Thar, Gobi, Tibet) & west Asia.
v Deserts are characterized by scanty flora & fauna.
v Soils of deserts often have abundant nutrients but little or no organic matter.
Sturucture and Functions of Desert Ecosystms
I. Biotic components
1) Producer Organisms
v In a desert, producers are mainly shrubs/bushes; some grasses & a few trees.
v Dominant plant species include: Succulents (water - retaining plants adapted to arid climate or soil conditions) & hardy grasses.
v Besides some lower plants such as lichens & xerophytic mosses are also present.
2) Consumer Organisms
These include animals such as insects, reptiles which are capable of living in xeric conditions
v Besides some nocturnal rodents, birds & some mammalians like camel etc are also found.
Due to poor vegetation with very low amount of dead organic matter, decomposers are poor in desert ecosystem.
v The common decomposers are some bacteria & fungi, most of which are thermophillic.
II. Abiotic components
Due to high temperature & very low rainfall, the organic substances are poorly present in the soil.