Differences in plant phenological traits and population dynamics related with the vegetation structure at the community level illustrate the mechanism for maintenance of diversity in desert plant communities. Vegetation analysis and plant phenological study were conducted in wadi Degla ecosystem for three consecutive years parallel with environmental variables including soil variables and climatic conditions. Eighty eight plant species recorded in the study area, twenty of which dominate different plant communities. There were various phenological patterns which differ in the flowering/fruiting time and the fruit setting among size classes, populations, years and community types. The reproductive success of gynodioecious populations of Ochradenus baccatus varied among size classes, population, sexes and seasons.