Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Vegetation dynamics of plant communities and species diversity in major habitats of Dakhla Oasis, Western Desert, Egypt

Auteur : Diaa Mostafa Mohamed Hasanin

Etablissement de soutenance : New Valley University

Grade : Master of Science (MS) In Botany 2021

Résumé partiel
The Egyptian Western Desert covers two-thirds of the total area of Egypt. Western Desert is also characterized by sand seas and sand dunes, a burning sun, winds and sandstorms, springs and wells, mountains and rocks, minerals and stones, plants and animals and a multitude of fossils. Sand dunes at different stages of development are numerous in the oases of the Western Desert. The significant oases in the Western Desert are (Siwa, Bahariya, Farafra, Dakhla and Kharga). Dakhla Oasis is one of the seven oases of Egypt’s Western Desert. Dakhla Oasis is located in the New Valley Governorate, 350 km from the Nile and between the Farafra and Kharga Oasis, which is about 190 km from Kharga. It is about 10-20 km from east to west and 250 km from north to south. Weather : 22°C, Wind N at 14 km/h, 24% Humidity. Dakhla Oasis extends between 25.5°N latitude and 29°E east longitude, and is 110-140 meters above sea level. During the growing seasons of 2017, vegetation was sampled from 47 permanently visited stands situated along N-S line transect across Dakhla Oasis, and extending for about 185 km to cover as much as possible the physiognomic variation in habitats. All the stands studied were geo-referenced using GPS technique. Four habitats were recognized in this study ; from inner to outer zones : farmlands and palm orchards represent the inner zone, the waste-salinized lands (not saltmarshes) in the middle, and the surrounding (bounding) desert in the outer zone. The farmlands included the major crops, wheat (Triticum aestivum L.), millet (Sorghum halepens L.) Moench, and the perennial alfaalfa (Medicago sativa L.). In each of the studied stand, presence or absence of plant species was recorded using a number of permanent stands randomly positioned and representing the variation in the floristic composition of these habitats. The studied stands covered the 4 recognized

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