Soil characteristics and plant distribution in saline wetlands of Oued Righ, northeastern Algeria

Abstract

Saline wetlands are rare ecosystems in Saharan areas, which are important for conservation of many endemic and rare plant species. In this study, we investigated five saline wetland sites of the Oued Righ region, located in the northeastern Algeria, to determine the environmental factors controlling the composition and distribution of plant communities. We established a total of 20 transects to measure the vegetation parameters (density and cover) and soil characteristics (electrical conductivity, moisture, pH, CaSO4, CaCO3, organic matter, Na+, K+, Mg2+, Ca2+, SO4 2–, Cl–, NO3 – and HCO3 –). A total of 17 plant species belonging to seven families were identified. The natural vegetation was composed of halophytic and hydro-halophytic plant communities, presented specially by the species of Amaranthaceae family. Soils in the studied wetlands were moist, gypsiferous, alkaline, salty to very salty with dominance of chloride and calcium. Results of the Canonical Correspondence Analysis (CCA) showed that community structure and species distribution patterns of vegetation were mainly dependent on soil characteristics, mainly being soil salinity (CaSO4, K+, Ca2+ and Cl–) and moisture. The distribution of plant species was found to follow a specific zonal pattern. Halocnemum strobilaceum was observed to grow in highly salt-affected soils, thus being the more salt-tolerant species. Phragmites communis plants were widely distributed in the study area with a high density at the edges of accumulated water body. Juncus maritimus, Tamarix gallica and Salicornia fructicosa grew in soils that are partially or completely flooded in winter. Suaeda fructicosa, Traganum nudatum, Arthrocnemum glaucum, Aeluropus littoralis, Cressa cretica and Cynodon dactylon were distributed in salty and moist soils away from the open water body. Plants of Zygophyllum album, Limonastrirum guyonianum, Cornulaca monacantha, Cistanche tinctoria, Mollugo nudicaulis and Sonchus maritimus were found in soils with less salty and moisture. They constituted the outermost belt of vegetation in the studied wetlands. This study will provide a reference on introducing the salt-tolerant plant species as a fodder resource in saline habitats and regenerating the degraded saline wetlands.