Species diversity and distribution along the Area Jeddah-Rabigh, Saudi Arabia

Abstract EN

The study assesses the plant communities and environ-mental factors that govern species diversity (alpha and beta diversity) and distribution in the area extending from Jeddah to Rabigh at the Red Sea coast.

Sixty-four plant species were recorded (43 perennials and 21 annuals).

Zygophyllum coccineum, Panicum turgidum and Cy-perus conglomeratus of perennials and Zygophyllum simplex of an-nuals attained high presence percentages in most of the selected stands.

Four vegetation groups with their sub-groups, which are present in the six different habitat types in the study area, were rec-ognized by applying NTSYS-PC classification technique.

Group A was divided into two subgroups, A1 that was indicated by Zy-gophyllum coccineum and Suaeda pruinosa and subgroup A2 that was indicated by Zygophyllum album and Acacia seyal.

Group B was also divided into two subgroups, B1 that was indicated by Limonium ax-illare and Cyperus conglomeratus and subgroup B2 that was indicated by Acacia tortilis and Heliotropium ramosissimum.

Group C was in-dicated by Indigofera spinosa and Panicum turgidum and group D was indicated by Acacia tortilis and Acacia ehrenbergiana.

Soil tex-ture, water holding capacity, Na, Ca and SO4 contents were the best predictor variables for species distribution in the study area.

The re-sults of beta diversity indicated that the study area must be divided into six different habitats.

Low species richness was associated with more saline conditions and mobile dunes in the study area.