Deserts and xeric shrublands

Deserts and xeric shrublands also called xerófila are a biome characterized by, relating to, or requiring only a small amount of moisture,^[1] usually defined as less than 250 mm of annual precipitation. It is the largest terrestrial biome, covering 19% of the earth's land surface area.^[2] They may be further characterized as hyperxerófila (very dry) and hypoxerófila (less dry).

Character of the biome

Biodiversity: Deserts and xeric shrublands may have a very diverse and rich flora. Reptile fauna may also be very diverse with pronounced local endemism in some regions.

Minimum resources: Many species track seasonally variable and patchy resources and require large natural landscapes to persist. Available water sources and riparian habitats are critical for the persistence of many species.

Poor soils: Because biomass productivity is low, the litter layer is almost nonexistent and the organic content of surface soil layers is very low. Also, evaporation tends to concentrate salts at the soil surface.

Sensitivity to disturbance: As the desert is highly sensitive to grazing, soil disturbance, burning, plowing, and other cover alteration; restoration potential can be very low and regeneration very slow. The introduction of exotic species may be a serious problem.

Desertification

The conversion of productive drylands to desert conditions, known as desertification, can occur from a variety of causes. One is human intervention, including intensive agricultural tillage or overgrazing^[3] in areas that cannot support such exploitation. Climatic shifts such as global warming or the Milankovitch cycle (which drives glacials and interglacials) also affect the pattern of deserts on Earth.

Desert and xeric shrublands ecoregions

See also

• Arid Forest Research Institute (AFRI)
• Xeriscaping- gardening or landscaping in xeric environments
• Xerophytes- plants adapted to xeric environments
• Shrub-steppe
• Temperate grasslands, savannas, and shrublands
• Sagebrush steppe
• Mesic
• Hydric

References

External links

• Deserts and xeric shrublands (World Wildlife Fund)
• Index to Deserts & Xeric Shrublands at bioimages.vanderbilt.edu
• Xeric World Online Community focused on the study of Xeric Plant Species.