Coastal lowland vegetation of eastern Saudi Arabia

Abstract

This study assesses the plant communities and environmental factors that govern species richness and distribution in the coastal lowlands of eastern Saudi Arabia using TWINSPAN, DCA and regression analyses. Thirty-four vegetation groups were identified, some of these occur in only one habitat: Juncus rigidus and Aeluropus lagopoides-Phragmites australis in the high saline flats, Plantago boissieri-Savignya parviflora, Panicum turgidum-Plantago boissieri-Moltkiopsis ciliata and Panicum turgidum-Haloxylon salicornicum in the non-saline flats, and Bassia eriophora-Launaea mucronata in the depressions between dunes. Some other groups are represented in at least four out of six studied habitats: Zygophyllum qatarense-Launaea capitata-Plantago boissieri, Zygophyllum qatarense-Plantago boissieri and Haloxylon salicornicum-Zygophyllum qatarense. Among 20 examined soil and community variables, regression analysis indicates that only six are influential in the stand ordination process (K, lime, sulphates, pH, plant cover and species richness). Some human impacts (e.g. grazing and cutting intensities) also play an important role. The nature of soil surface and salinity are the main factors that affect the species richness.