Distribution Pattern of Aquatic Macrophytic Community and Water Quality Indicators in Upper and Lower Litani River Basins, Lebanon

In spite of their important role in the structure and function of river ecosystems, aquatic macrophytes of freshwater bodies in Lebanon have so far received very little attention. In the present study, comparative analysis of the composition and spatial distribution of macrophytic communities and water quality indicators were assessed between Upper and Lower Litani River Basins in Lebanon. Five sites distributed along River Basins which are separated by Qaraoun Dam and its reservoirs were investigated during 2013-2014. A total of 35 of both submersed and emergent macrophytes were observed. FCA analysis revealed the presence of a heterogeneous spatial distribution pattern of the communities between the Upper and Lower River Basins. Two principle taxa units each characterizing either of the river basins were identified. Corresponding water quality analysis also showed heterogeneous spatial distribution and high levels of eutrophication of the Upper Basin and better quality conditions of the Lower Basin and CCA analysis highlighted the distinctive ecological features of macrophytic associations with respect to water quality parameters and trophic conditions of studied sites. These results clearly indicate the influence of nutrient enrichment in the determination of macrophyte assemblages and role of Qaraoun reservoir in the observed discontinuity of the taxa between the Upper and Lower basins and reducing the eutrophication level in the Lower Basin. Monitoring of macrophytes could, thus, be a reliable means to assess the ecological status of Litani River.