Vegetation Structure and Diversity of Wadi Wasaa, Jazan, Saudi Arabia

Aims: To study vegetation, life-form and chorotype to assess the species diversity between the different community types.

Study Design: Several field trips were carried out to the study area.

Place and Duration of Study: Wadi Wasaa - Jazan - Saudi Arabia.

Methodology: Vegetation diversity, chorology and abundance values were visually estimated and used to form ten clusters of plant community types by statistical methods with Euclidian Distance and Ward method using SPSS program (ver.20). The Shannon-Wiener diversity index was used to estimate diversity, richness and evenness of the recorded species.

Results: A total of 95 species belonging to 75 genera and 31 families were recorded. Poaceae and Euphorbiaceae both are the dominant families constituted 23% of the total species followed by Apocynaceae, Malvaceae. Chamaephytes and therophytes were the prevailed life forms, indicating a typical desert life-form spectrum (chameo-therophytic) type. The chorological analysis revealed a total of 26 species representing 27% fall under monoregional, 56 species (59%) as biregional area and four species were detected under pluriregional region. The highest diversity index (H) was detected in Tamarindus indica community, followed by Acacia asak, whereas the lowest one was calculated in Lawsonia inermis.

Conclusion: Ten plant community types in the wadi were observed. I-Ziziphus spina-christi, II- Salvadora persica III- Anisotes trisulcus, IV- Adenium obesum, V- Ricinus communis. VI-Acacia asak, VII- Lawsonia inermis, VIII- Dobera glabra, IX-Tamarindus indica and X- Leptadenia arborea.