| Abstrakt: |
The vegetation-soil relationships in the four major habitats of Kharga Oasis (farmlands, date-palm orchards, salinized lands and the surrounding desert) in the Western Desert of Egypt are examined in this study. Altogether, 122 vascular plants species distributed in 102 genera and thirty-five families were recorded. Poaceae (25.2 %), Asteraceae (11.9 %), Brassicaceae (6.5 %), Cyperaceae (6.5 %), Amaranthaceae (5.4 %) and Euphorbiaceae (5.4 %) were the largest families. With respect to the floristic composition, habitats varied from one to another: eighty-six species in farmlands, seventy-nine species in date-palm orchards, seventy-three species in salinized lands and thirty-nine species in the surrounding desert lands. About 22 % of the total flora was represented in the four habitats, while 37.7 % was found in one habitat. The vegetation classificatory method of Two-Way Indicator Species Analysis yielded fourteen vegetation groups: four in both farmlands and date-palm orchards, and three for both salinized lands and the surrounding desert habitats. The results of the Canonical Correspondence Analysis (CCA) showed that water content, soil texture, organic matter and bicarbonates were most related to the species distribution in the studied habitats. Other related variables included sulfates and phosphates in the date-palm orchards and salinized lands, and electric conductivity in the surrounding desert. Farmlands had the highest species richness, followed by the date-palm orchards and the salinized lands, whereas the desert outskirts were the lowest in terms of species richness. The linear correlations (r) between the farmlands and palm orchards were highly significant (r = 0.703), and also occurred between salinized lands and the surrounding deserts (r = 0.764). These high correlations may be attributed to the effect of concentric zonation of the habitat as each pair of the aforementioned habitats is adjacent to each other. [ABSTRACT FROM AUTHOR] |
