Phreatophyte - Biological Value

Biological Value

They are plants of great ecological value, fast growing pioneers and highly resistant to disease. They make excellent fodder for livestock and provide nesting areas and shelter for fauna. They are used as fuel, cheap construction material, and basketry. Many of the plants grow in degraded waters, salty or saline, that are useless for agriculture. Phreatophyte plants help to purify these waters and their roots fix heavy metals with a bacteria filter. For example, it is estimated that the total annual groundwater phreatophytes consumed in the western U.S. alone is about 30,000 hm.

Phreatophytes are indicators of potable groundwater. Phreatophytes can be differentiated into plant communities by the length of their root, as they extend more or less deeply into the aquifer. Meinzer Studies. O.E. (1927) and Robinson, T.W. (1958) on vascular plants in the arid western U.S., set up certain general types of indicator species, according to level of minimum depth of the water table at which water was at the maximum suction RO.

Some phreatophytes have a low tolerance for salt, indicating freshwater. This can be a valuable guide to the location of drinking and agricultural water in arid and semiarid areas. Examples of phreatophytes include welwitschia and mesquite: Prosopis glandulosa. The alfalfa, or Medicago sativa, is a widespread phreatophyte plant of great economic value. Trees like the Ash, the Alder, the Willow and the Poplar are also useful in this regard. These trees generally grow in freshwater aquifers where the water table depth is not more than ten meters.

These species are found in riparian ecosystems and areas characterized by shallow groundwater, such as bottomlands. They are also present in water limited environments; for example, Oaks in the Mediterranean climate regions.