Phragmites australis (Poaceae) is a cosmopolitan reed grass, so far reported only in Eastern Region of Saudi Arabia. Our recent field exploration in the South West Region of Saudi Arabia resulted in documentation of this species in Gizan City (Jazan Region). The species is reported here as a first record in Jazan Region and an addition to Jazan flora. A note on distribution, ecology, and brief description of the plant is also provided.

Background and Objective: Although desert dams create storage reservoirs that recharge ground water, irrigate desert agriculture and protect against flash floods, there is controversy about their effects on ecosystem. Work in this study was carried out to provide first environmental impact assessment of Wadi Jazan desert reservoir by studying its effects on soil and floristic composition. Materials and Methods: Soil analysis included studies of soil types and characteristics. Vegetation analysis included study of plant distribution, life forms, growth habits, carbon isotope discrimination, CO 2 fixation pathways, species drought and salt tolerance ranges. Results: Soil analysis revealed changes in soil type around reservoir from common sand-silt to clay and clay-loam types reflecting reservoir-induced changes in sedimentation patterns. Soil analysis also revealed increased soil electric conductivity and total dissolved solids in reservoir vicinity denoting increased soil salinity. High reservoir level during wet season enables water to cover vast areas with subsequent evaporation during long hot dry season resulting in salt accumulation and increased soil salinity. Vegetation analysis revealed prevalence of salt tolerant C3 species in saline soil in reservoir vicinity that was reversed with prevalence of C4 drought tolerant species as distance from reservoir increased. Presence of non-native aquatic and wetland species are due to recruitment facilitated by reservoir. Conclusion: Wadi Jazan desert reservoir modified sedimentation pattern, facilitated establishment of invasive aquatic plants and induced changes in regional floristic diversity and distribution.

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Work aimed at assessing status and introducing water conservation regimes for coffee production in southern Saudi Arabian highlands. Data on farm locations, altitudes, areas, practices, irrigation, tree density, and annual coffee production were analyzed. Field experiment using chlorophyll fluorescence and different irrigation regimes was conducted to examine effects of reducing irrigation frequency on photosynthesis. Results indicated that Coffea arabica L. is commonly grown at altitudes of 1300–1400 m. Plants grown at 4–6 Trees m−2 using 100 kg ha−1 mineral fertilizer produce an average of 3 t ha−1. High frequency 2-day-intervals irrigation regime practiced by farmers during the dry season presents ecological challenge to limited local artesian water resources. Changes in chlorophyll fluorescence under 14-day-intervals irrigation regime initiated water stress that markedly inhibited Photosystem II efficiency and quantum yield and increased non-photochemical energy dissipation. Applying a 7-day-intervals irrigation regime induced less inhibitory effects on Photosystem II. Results also indicated that shifting from 2-day-intervals irrigation regime to 7-day-intervals regime improves coffee agroecology and directs coffee production towards sustainability.

SUMMARYTwo new species of Schizostachyum Nees: S. andamanicum and S. kalpongianum, are described and illustrated.