Biological Soil Crusts and Extremophiles Adjacent to Native Plants at Sabkhas and Rawdahs, Qatar: The Possible Roles

Several studies have investigated the biology of native plants (halophytes and xerophytes), biological soil crusts (BSC), as well as the associated and adjacent microorganisms. These studies concentrated on their eco-physiological aspects as well as the possible roles they might play in various life activities and industries. This article presents the mechanisms adopted by these living organisms to cope with the harsh environment, and the possible roles microorganisms might play to support native plants, some important examples from the flora of Qatar are presented to show these mechanisms. Special attention has been paid to the senescence and death of leaves or whole plants, since this strategy has been considered as an important option for escaping extreme environmental conditions. Discussion about solute accumulation (organic and inorganic) in all native living organisms in general and in microorganisms in particular, could result to further investigation to clarify their roles in such an ecosystem. Some case studies have been reported to discuss the ecological aspects at two main types of habitats in Qatar; Rawdahs and Sabkhas were chosen to show how native living organisms adapt in these habitats. This study discussed the general identification of BSC and microorganisms, as well as their possible roles in the soil biota. The possible methods and mechanisms exhibited by extremophiles to support native plants in coping with saline and arid lands have also been reported in this article. This study also discussed the recent outlook about the origin of metabolic activities in these living organisms to support the growth of native plants under stress conditions