Vegetation Dynamics and Species Diversity in a Saharan Oasis, Egypt

Abstract

The present study provides an analysis of the floristic composition, habitat types, vegetation structure and species diversity, elucidating the role of the environmental factors that affect species distribution in Kharga Oasis, Western Desert, Egypt. The vegetation was sampled from 89 permanently visited stands in 12 sites situated along N - S line transect across the oasis, and extending for about 185 km to cover as much as possible the physiognomic variation in habitats. Four main habitats were recognized and forming concentric zones (from inside to outside): farmlands and date-palm orchards represent the inner zone, the waste-salinized lands (not saltmarshes) in the middle zone, and the surrounding (bounding) desert in the outer zone. A total of 122 species from 35 families and 102 genera represented the flora of the study area. Poaceae, Asteraceae and Fabaceae were the major families, which constituted 47% of the total flora. Classification using Bray-Curtis cluster analysis produced 4 vegetation groups (A - D); each can be linked to a certain habitat. The arrangement of habitat zones along the first DCA axis can be noticed: outer zone (bounding desert), middle zone (waste-salinized lands) and inner zone (arable lands). On the other hand, farmlands and date-palm orchard groups were separated from each other along the second DCA axis. The relationship between the vegetation and soil variables was studied using Canonical Correspondence Analysis (CCA); it was indicated the most important environmental gradients those control the vegetation composition and the distribution pattern of species in Kharga Oasis, which were mainly related to gradients in soil moisture content and fine fractions. The present situation of Kharga Oasis urges the conservation of some old historic wells and the naturally growing open dom-palm forests before vanishing due to high human activities in the area.

Do Anthropogenic Activities Affect Floristic Diversity and Vegetation Structure More Than Natural Soil Properties in Hyper-Arid Desert Environments?

“…The overall floristic analysis of the study areas showed that the majority (48.2%) of the recorded flora belonged to five plant families: Asteraceae, Chenopodiaceae, Fabaceae, Zygophyllaceae, and Poaceae. This result was also consistent with those in adjacent areas in the arid region, e.g., El-Ghanem et al [78], Alatar et al [25], Shaheen et al [79], Zhang et al [71], Salama et al [80], and Croce et al [81] in Kuwait, Saudi Arabia, Pakistan, China, Egypt, and southern Italy, respectively. According to Pielou [68] and Magurran [69], the taxonomic range is higher in an area in which species are distributed among several genera than in which the most species belong to the same genus.…”

“…This study also indicated the disappearance of several plant communities that were previously of common occurrence, such as Retama raetam, Anabasis articulata, Ephedra alata, Artemisia monosperma, Zygophyllum decumbens, Lasiurus hirsutus, and Panicum turgidum. Most of the identified vegetation groups have analogues with others recorded in some wadis of the Eastern Desert [73,104], Western Desert [88,105], along the western Mediterranean region [106], in the South Sinai region [107,108], and in northwestern Negev, Israel [109]. This result can be directly related to the severe uncontrolled human disturbances (especially urbanization) along both sides of this road (Figure 6), where the vegetation is removed from nearly half of its length.…”

Utilization of Sugar Beet by Products in Feeding Grow-Ing Rahmani Lambs

“…Similar results found that introducing DSBP in rations of buffaloes and sheep resulted in an increase in CF content (10, 25). Also, replacing BH by DSBT in rabbit's ration decreased CF content and increased NFE and ash contents (13).…”

Water Quality Assessment of Ogbese River, Ekiti State Using Biological Approaches

“…Community structure analysis: The three community structure indices used include, Margalefʼs diversity index (d), Shannon-Wiener index (H1) and Species Equitability (j) or Evenness 15,16 .…”