Biodiversity of halophytic and sabkha ecosystems in Iran

Abstract

Iran, with a total surface area of 1.6 Mkm2, is a typical country of large sabkhas, littoral and inland salt marshes, and diverse brackish and salty river ecosystems. According to our present knowledge and evaluation of new data, a total of 365 species within 151 genera and 44 families of Ir anian vascular plants are known to be true halophytes, or species capable of successful growth on salty soils. The Chenopodiaceae family with 139 species ranks first, followed by the Poaceae (35), Tamaricaceae (29), Asteraceae (23) and Plumbaginaceae (14). The genus Salsola with 28 species, Tamarix with 25, Atriplex and Suaeda each with 15 and Limonium with 10 species, respectively, are the largest halophytic genera in Iran. Diverse eco- and morphotypes, anatomical features, life forms and photosynthetic pathways allow the halophytes of Iran to inhabit various ecological conditions from very high (an EC over 200 ds/m) to low salinity soils, and from sea water to very dry, salty and gypsum soils. In spite of a vast expanse of salty soils, the halophytic communities in Iran are in danger because of extensive damming, which has led to the drying out of many rivers and wetlands, deformation of salt depressions and overgrazing. A list of 28 endangered halophytes is presented here, with the knowledge that some species are on the verge of extinction. A short discussion of the economic and biotechnological potential of Iranian halophytes is given, including the emergence of a new vegetable crop in southern Iran (Suaeda aegyptiaca) and the opening of new opportunities in plant biology that have arisen from the discovery of C4 photosynthesis without Kranz anatomy in Bienertia cycloptera and B. sinuspersici (Chenopodiaceae). 1.