Phytosociological survey of the desert vegetation of Sinai, Egypt

Hatim, Mohamed Z.; Janssen, John A.M.; Pätsch, Ricarda; Shaltout, Kamal; Schaminée, Joop H.J.


Aims: Although Sinai is a global hotspot for desert vegetation, there is no well-documented overview of the Sinai vegetation. We aim to provide a phytosociological overview of Sinai desert vegetation based on an extensive database and formal classification. We further aim to describe the vegetation communities and provide information on their distribution. Location: Sinai, Egypt. Methods: We built a comprehensive database utilizing all available vegetation plot data of the study area from published literature and our field surveys. We determined the database clustering tendency (Hopkins’ test analysis) and estimated its optimal number of clusters (Elbow method). We performed a cluster analysis (modified TWINSPAN) and improved the validity of the resulting groups by approximating natural clustering using the Silhouette algorithm. We visualized the results by calculating Non-metric Multidimensional Scaling and drawing distribution maps for the observed vegetation communities. Results: We distinguished nine classes representing Sinai desert vegetation: Salicornietea fruticosae, Retametea raetam, Haloxylonetea salicornici, Retamo-Tamaricetea fluviatilis, Acacietea tortilis, Artemisietea herbae-albae, Anabasietea articulatae, Chiliadenetea iphionoidis, and Stellarietea mediae. We distinguished 25 vegetation groups, of which seven are new findings, representing four main vegetation groups: salt desert, lowland desert, mountain desert, and ruderal desert. We observed a high diversity in life forms, chorotypes, and alpha-diversity of the vegetation among the main groups. Therophytes, chamaephytes, hemicryptophytes, and phanerophytes are the dominant life forms. Prevailing chorotypes are Saharo-Arabian, Mediterranean, Mediterranean-Irano-Turanian and Irano-Turanian-Saharo-Arabian. The salt desert and lowland desert vegetation are species-poor, whereas the mountain desert vegetation is relatively species-rich. The ruderal desert vegetation is the most species-rich. Conclusion: We present a common classification of Sinai desert vegetation based on cutting-edge methods and provide an updated description of the desert vegetation groups of Sinai. Our study forms an important basis for decision-making in nature conservation, global change issues, and further in-depth studies on Sinai vegetation.