Characteristics of nabkhas in relation to dominant perennial plant species in Kuwait

Nabkhas are stabilized dunes formed around desert and sabkha perennial plants. Field studies were conducted and approximately 500 sediment samples were collected from surface and subsurface of nabkhas that developed around dominant perennial plant species in Kuwait. The desert (non-saline) nabkhas are those forms around plants such as Cyperus conglomeratus, Haloxylon salicornicum, Rhanterium epapposum, Astragalus spinosus, Lycium shawii, Citrulus colocynthis and Panicum turgidum in the study area, while saline (sabkha) nabkhas form around halophytes such as Nitraria retusa, Tamarix aucheriana, Halocnemum strobilaceum and Salicornia europaea. The presence of desert plants such as Cyperus sp., Haloxylon sp and Rhanterium sp. is a good indicator of highest severity of aeolian processes. The nabkha sediments of these three plant species have high pH values and low electrical conductivity (EC) and moisture percentage values. They are also characterized by shorter distances between plant branches and surrounding nabkhas. The nabkhas around Astragalus sp are characterized by the finest mean grain size and high carbonate content due to its growth on the lower stage of the wadis downstream on delta alluvial deposits resulted during recent flood seasons. Citrulus sp is the shortest plant and its nabkhas have the highest carbonate contents among the desert plants, as well as the lowest pH, EC and moisture percentage. Lycium sp has the largest spacing between branches and greatest distances to the same neighboring species. On the other hand, sabkha nabkhas have different morphological and ecological functions from those in desert nabkhas. The presence of thriving nabkhas within a salty sabkha environment is attributed to the existence of the shallow fresh groundwater lenses floating on the saline water bodies that are recharged by rainwater and the surface drainage paths. The recharging process was proven in this study through a 15 month period of monthly monitoring for the groundwater level and total dissolved solids (TDS) in three wells, one in a group of nabkhas in one sand body around Nitraria retusa and the other in sabkha level beside the nabkha.. The sediments of the sabkha nabkhas have lower pH and carbonates content, and higher values of moisture, TDS and EC than those in desert nabkhas. The Nitraria retusa from the sabkha environment and Haloxylon salicornicum from open desert environment are the most efficient plant species in trapping mobile sand