Vegetation and Environment of the Western Mediterranean Coastal Land of Egypt: II. The Habitat of Inland Ridges

Abstract

The Mediterranean coastal land west of Rosetta is vegetationally and floristically the richest part of Egypt. Owing to the nature of sediments, this region is differentiated into an eastern zone extending from Rosetta to Alexandria, and a western zone from Alexandria to Sallum near the Lybian border. The sediments in the eastern zone are poor in carbonate content and relatively dark in colour due to enrichment with clay minerals deposited by the Nile; those in the western zone are composed mainly of calcareous grains which are much less contaminated by clay deposits. The latter zone, which is referred to as Mareotis (or Mariut) is characterized by a variety of landforms which display varied environmental and vegetational spectra. This is especially obvious in the Burg El-Arab area where a series of ridges alternating with depressions run parallel to the coast (Fig. 1). Accordingly, two sets of habitats are distinguishable, one on ridges and the other in depressions. Ridge habitats may be further differentiated into two main types: that of the coastal ridge which is composed mainly of snow-white calcareous sand grains and is overlain by dunes, and that of inland less calcareous ridges. Habitats of depressions differ according to the relative proximity of water table to the soil surface, and consequently the level of salinity and the extent of waterlogging. This paper is the first in a series of studies with the aim of providing quantitative descriptions of the vegetation and environment of these habitats. It includes an assessment of the relationships between the distributional behaviour of species and local environmental variations in the habitat of sand dunes.