The dataset contains records of vascular plants collected in the lower valley of River Sabor (NE Portugal) in the scope of the long-term Ecological Monitoring Program (PME) of the Baixo Sabor Hydroelectric Dams (AHBS), promoted by EDP – Energias de Portugal, S.A, to assess the temporal dynamics of selected habitats of conservation relevance, before and after the dams implantation. This dataset includes results of surveys made in and around the area affected by the dams, from May 2010 to August 2014. Plant inventories were made along the lower Sabor river valley and in some tributaries, from the river mouth up to 42 km upstream.