Friday, January 21, 2011

Ecological Systems: Salt Shrub

example of salt shrub

Salt shrubland ecosystem types are typically dominated by saltbush species or other shrubs tolerant of saline or alkaline soils typically derived from marine shales, siltstones and clay. These sparse to moderately dense low-growing shrublands are widespread at lower elevations (generally from 4,500 to 7,000 feet) in Colorado's western valleys, and are also found in more limited distribution in the southern part of the eastern plains. In addition to mid-height and dwarf saltbush species, the shrub layer may include winterfat, wolfberry, horsebrush, and sagebrush species. Grasses and forbs are generally sparse, and dominated by species tolerant of these harsh soils. Some areas are essentially barren, or very sparsely vegetated.

These arid habitats support desert species such as the lesser earless lizard, desert spiney lizard, and the common kingsnake, but provide limited food and cover for mammal or bird species. White-tailed prairie dogs may be found in areas with sufficient vegetation. These barren and sparse shrubland habitats of shaley soils are one of the most important for Colorado's rare plants, including the federally listed endangered wild clay-loving buckwheat, and the threatened Mesa Verde cactus and Colorado hookless cactus.

Holbrookia maculata
The lesser earless lizard (Holbrookia maculata)

Sclerocactus mesae-verde
The Sclerocactus mesae-verde (Mesa Verde cactus) in bloom

Salt shrublands cover more than 750,000 acres in Colorado, primarily on federal lands managed by the Bureau of Land Management, and the remainder on private or tribal lands. Protection of these habitats is weak; few salt shrublands are within protected areas with special management in place. A substantial portion of these shrublands have been converted to agricultural use in valley bottoms where irrigation is available. Because remaining occurrances are generally not productive agricultural or ranching lands many are in good condition. Impacts and fragmentation from energy development are the most current threats to this type.

Overall biodiversity, threat, and protection status scores for salt shrub in Colorado.

A "windrose" graph depicting salt shrub status for individual scoring factors.

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