Deserts and xeric shrublands
Deserts and xeric shrublands are a biome characterized by receiving only a small amount of moisture,[1] usually defined as less than 250 mm of annual precipitation. They form the largest terrestrial biome, covering 19% of Earth's land surface area.[2]
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
| Carnarvon xeric shrublands | Australia |
| Central Ranges xeric scrub | Australia |
| Gibson Desert | Australia |
| Great Sandy–Tanami Desert | Australia |
| Great Victoria Desert | Australia |
| Nullarbor Plain xeric shrublands | Australia |
| Pilbara shrublands | Australia |
| Simpson Desert | Australia |
| Tirari–Sturt stony desert | Australia |
| Western Australian mulga shrublands | Australia |
| Deccan thorn scrub forests | India, Sri Lanka |
| Indus Valley desert | India, Pakistan |
| Northwestern thorn scrub forests | India, Pakistan |
| Thar desert | India, Pakistan |
| Baja California desert | Mexico |
| Central Mexican matorral | Mexico |
| Chihuahuan desert | Mexico, United States |
| Colorado Plateau shrublands | United States |
| Great Basin shrub steppe | United States |
| Gulf of California xeric scrub | Mexico |
| Meseta Central matorral | Mexico |
| Mojave desert | United States |
| Okanagan (South) shrub steppe | Canada |
| Snake-Columbia shrub steppe | United States |
| Sonoran desert | Mexico, United States |
| Tamaulipan matorral | Mexico, |
| Tamaulipan mezquital | Mexico, United States |
| Wyoming Basin shrub steppe | United States |
| Araya and Paria xeric scrub | Venezuela |
| Aruba-Curaçao-Bonaire cactus scrub | Aruba, Bonaire, Curaçao |
| Atacama desert | Chile, Peru |
| Caatinga | Brazil |
| Cayman Islands xeric scrub | Cayman Islands |
| Cuban cactus scrub | Cuba |
| Galápagos Islands xeric scrub | Ecuador |
| Guajira-Barranquilla xeric scrub | Colombia, Venezuela |
| La Costa xeric shrublands | Venezuela |
| Leeward Islands xeric scrub | Anguilla, Antigua and Barbuda, British Virgin Islands, Guadeloupe, Saint Martin, Saint Barthélemy, Saba, US Virgin Islands |
| Malpelo Island xeric scrub | Colombia |
| Motagua Valley thornscrub | Guatemala |
| Paraguana xeric scrub | Venezuela |
| San Lucan xeric scrub | Mexico |
| Sechura desert | Peru |
| Tehuacán Valley matorral | Mexico |
| Windward Islands xeric scrub | Barbados, Dominica, Grenada, Martinique, Saint Lucia, Saint Vincent and the Grenadines |
| Saint Peter and Saint Paul Archipelago | Brazil |
See also
- Arid Forest Research Institute (AFRI)
- Hydric
- Mesic
- Sagebrush steppe
- Shrub-steppe
- Temperate grasslands, savannas, and shrublands
- Xeriscaping—gardening or landscaping in xeric environments
- Xerophytes—plants adapted to xeric environments
References
- ↑ Merriam-Webster.com Merriam-Webster Dictionary definition of xeric
- ↑ Lockwood, M. Managing Protected Areas: A Global Guide. p. 199.
- ↑ C. Michael Hogan. 2009. "Overgrazing". Encyclopedia of Earth. Sidney Draggan, topic ed.; Cutler J. Cleveland, ed., National council for Science and the Environment, Washington, D.C.
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