| ABSTRACT |
The vegetation-environment relationships in the inland saltmarshes of two geographically distant oases of the Western Desert of Egypt, Siwa, and Dakhla Oases, are described. Two data sets (25 species × 68 stands for Siwa Oasis and 29 species × 89 stands for Dakhla Oasis) were analysed, using multivariate procedures, i.e., two-way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA), and detrended canonical correspondence analysis (DCCA), to produce a classification of plant communities in the studied areas, and to examine the relationships of these plant communities to certain edaphic factors, namely soil reaction, total soluble salts, calcium carbonate, organic matter, moisture content, and fine fractions. Twelve halophytic plant communities linked to two main habitats (wet-moist and dry-mesic) were identified. Alhagi graecorum, Tamarix nilotica, Cressa cretica, Juncus rigidus and Phragmites australis were the most common in the two oases. Whereas communities of Cyperus laevigatus, Suaeda aegyptiaca, Suaeda vermiculata, Typha domingensis, and Aeluropus lagopoides are recorded from the Dakhla Oasis, Cladium mariscus and Arthrocnemum macrostachyum communities are recorded from the Siwa Oasis. The most important edaphic variables affecting the distribution and structure of the plant communities are salinity, moisture content and fine fractions, nevertheless CaCO3 content seems to be more effective in the Dakhla Oasis. A new agricultural strategy that minimizes the increase of salinized lands is called for. |
