Ecology of saltcedar—A plea for research

Abstract

/ Because of the interdisciplinary requirements of studies of river-floodplain systems, development of this field in the United States has been slow, and much information needed for watershed and river-basin planning is not available. This is particularly true in the southwestern United States, where study has been further complicated within the last 50 years by the introduction and spread of saltcedar (Tamarix chinensis)which has occurred simultaneously with other independently generated environmental changes.The spread of saltcedar has been aided both by purposeful planting and by a fortuitous combination of events that has weakened the native ecosystem at the time that seeds ot the new species have been made available, events that possibly include changes in such environmental parameters as flood frequency, channel stability, the season of the peak annual flood, water temperature and salinity, and sediment grain size. Careful research is needed to unravel and understand the network of relationships involved.Phenomena are arranged in chains of necessary sequence .... If we examine any link of the chain, we find it has more than one antecedent and more than one consequent .... Antecedent and consequent relations are therefore not merely linear, but constitute a plexus; and this plexus pervades nature. (Gilbert, 1886, p. 285-286).

Remote Sensing and Mapping of Tamarisk along the Colorado River, USA: A Comparative Use of Summer-Acquired Hyperion, Thematic Mapper and QuickBird Data

“…or saltcedar) is a well-known invasive phreatophyte introduced from Asia to North America in the 1800s as an ornamental or shade plant used subsequently for erosion control [3]. In the western USA, it occupies over 600,000 ha of riparian habitat [4] and continues to spread in semi-arid regions, consuming valuable resources [5][6][7]. Western states heavily infested with tamarisk include Texas, New Mexico, Colorado and California, where dense stands impact native vegetation and cause extensive groundwater loss [8].…”

Downstream effects of dams on alluvial rivers

“…Saltcedar growth, for example, is highly suspect as an indicator of the effects of flow regulation. This plant has been spreading at a rapid rate along innumerable valleys in the southwestern United States since its introduction late in the 18th century (Everitt, 1980). Although many of the valleys into which it has spread have been subjected to flow regulation, reaches or sections of many others have not.…”

Historical channel-planform change of the Little Colorado River near Winslow, Arizona

“…The effects of tamarisk on the geomorphology of dryland rivers have also been long disputed (for example, Robinson, 1965;Graf, 1978;Everitt, 1980). In general, the spread of tamarisk in riparian corridors of the Western United States is assumed to cause channel constriction through (1) excessive consumption of groundwater or (2) stabilization of biomass density (Graf, 1978).…”