Spatial distribution and soil characteristics of the vegetation associated with common succulent plants in Egypt

Abstract

The most succulent species-rich family in Egypt is Chenopodiaceae, followed by Aizoaceae and then Zygophyllaceae, Crassulaceae, and Orobanchaceae. The Sinai Peninsula and the Mediterranean regions include most of these succulent species, at 73.2% and 53.7%, respectively. A floristic data matrix (59 stands and 137 species) was subjected to classification by 2-way indicator species analysis (TWINSPAN). This yielded 8 vegetation groups. The most prominent groups were the Mesembryanthemum crystallinum-Mesembryanthemum nodiflorum group, the Anabasis articulata group, the Zygophyllum coccineum-Zilla spinosa group, and the Zygophyllum album group. The vegetation associated with the 5 most common succulent plants was analyzed, and variations in floristic composition were described. Sixteen soil physical and chemical parameters from stands dominated by each of the studied succulent plants were analyzed. This investigation demonstrated the role of 12 soil factors in affecting the distribution of the 5 studied succulent plants: electric conductivity, pH, bicarbonates, sulfates, CaCO_{3}^{++}, Ca^{++}, Mg^{++}, K^+, Na^+, Cl^-, silt, and sand. The application of canonical correspondence analysis indicated that the distribution of Arthrocnemum macrostachyum was affected by Mg and electric conductivity; Zygophyllum album was affected by SO_{4}^{++}, electric conductivity, and Ca^{++}; and Anabasis articulata, Haloxylon salicornicum, and Zygophyllum coccineum were highly affected by percentages of sand and clay and values of CaCO_3, total mineral nitrogen, and pH.