Habitat and Plant Communities in the Egyptian Desert: VI. The Units of a Desert Ecosystem

Abstract

Plant growth of the wadi beds within a 2000 km2 area of the limestone desert east of Cairo is described. 13 community types are recognized. Each type is characterized by one dominant species. The main difference between the phytocoenoses of the various vegetation units (community types) is due to the behavior of the species and not necessarily to differences in the floristic composition. Each community type is referred to a discrete habitat type as a prerequisite of its identity; the community type is an ecocoenosis. The community types are syndynamically related. The change from one stage to the next, in the upgrade series, is due to the gradual building of the wadi-fill deposits. This is mainly a physical process (allogenic succession). Vegetational classification in the desert should rest on bases of dynamic and ecological relationships.