Flora

The flora of the UAE contains more than 630 species, and comprises elements from both Asia and Africa. In addition there are about 20 bryophyte species (Kürschner and B?er 1999). The permanent vegetation pattern is formed essentially of perennial xerophytes, psammophytes, and halophytes. However, the greatest number of species recorded in the UAE are therophytes. These appear after rains and disappear in dry periods.The natural wealth of the UAE flora may be ecologically categorised into several main vegetation types, namely: seagrass, mangrove, salt marsh, reed swamp, sand dune, gravel plain, desert wadis, and rocky-mountainous vegetation. Apart from these, there are several oases with date palm vegetation, and urban green areas within the UAE. The overall scientific knowledge on UAE flora and vegetation, major ecosystems, the potential economic value, and the status of conservation are described.

The vegetation of the UAE is sparse, due to the harsh environmental conditions. The soils are of the aridosol type: poorly developed, sandy in nature, alkaline in reaction, with low water contents, nutrients and organic matter. Some important relationships between UAE desert plans and soil parameters, such as salinity, grain size and surface hardness, were recently documented by B?er and Sargeant (1998). The climate is generally arid with low precipitation rates, high air temperatures and high evaporation rates (B?er 1995b, 1997). Thus, the water and nutrient availability to the plants is limited. Such harsh environmental factors have their impact on the plant life. The vegetation is scarce with low ground cover rates, densities and bio-diversities. The flora of the UAE mainly comprises thorny shrubs, therophytes (ephemerals, annuals, biennuals), xerophytes, psammophytes and halophytes. Also, there are some hygrophytes growing in the shaded humid wadis of the mountains, and some hydrophytes in the inundated ecosystems of the UAE.