Assessment of aquatic and semi-aquatic plants in arid regions: Testing factors affecting riparian plant distribution in the Draa Basin, Morocco

The main objective of this work was to study the richness and the effect of abiotic and anthropogenic factors on the distribution of riparian plant in Draa basin, which is part of the Oasis Biosphere Reserve located in South-East of Morocco. For this purpose, water quality parameters such as temperature, pH, salinity, electrical conductivity, Dissolved Oxygen, nitrate and phosphorus concentration, and riparian plants diversity were estimated at 12 stations along the Draa River and its tributaries using phytoecological surveys. The Canonical Correspondence Analysis (CCA) was performed to assess the relationship between environmental parameters, the distribution and abundance of riparian plants inventoried. \nThe results of the assessment of 12 phytoecological surveys revealed the existence of 86 species of aquatic and semi aquatic plants, divided into 76 genera and 30 botanical families, with 15.11% of the species are endemic and 9.30% as rare and threatened species. The Canonical Correspondence Analysis (CCA) results revealed that the salinity, the conductivity, degree of submersion and the nitrate concentration are the main factors affecting the composition and the distribution of the riparian plants in Draa basin. \nGiven the increasing human pressure on native riparian plant in the Mediterranean biodiversity hotspot region, including the climate change effects and habitat loss, urgent conservation measures are discussed for this and other riparian plant species.