This report provides a characterization of the riparian and terrestrial Ecological Relevant Units (ERU) in the Mediterranean sampling areas established under the Connectivity of forest and riparian ecosystems of the SUDOE space (CERES) project (CERES Interreg IV-B SUDOE-SOE2/P5/F0551). Portugal represents the Mediterranean ecoregion in the CERES consortium, with two case studies located in Tagus basin, the Sorraia and Almonda. The two areas have distinct land use matrices: an intensive agricultural production system dominated by irrigated croplands, a forest production system characterized by eucalyptus and pine forests, and an agroforestry system dominated by cork oak and holm oak trees. The report provides an initial section containing the maps and a spatial landscape metrics characterization of the Ecological Relevant Units in the two study areas. The maps were obtained through the visual classification of the ERU patches using high spatial resolution aerial images, and validated by field campaigns. ERUs were classified by taking into account the dominant ecosystem where they are located (riparian ecosystem or forest ecosystem) and the dominant strata (woody or herbaceous). The fallowing sections of the report describe the methodological framework and the main results concerning the potential biodiversity, the floristic composition and the biological characterization of the ERUs. Ants, dummy caterpillars and chiropterans were selected for the Mediterranean region as biological indicators, as they simultaneous provide biodiversity measures (richness and abundance) and ecosystem services (pest predation, seed dispersal and soil enrichment). The last section of the report contains a connectivity analysis of the ERUs ), in the distinct land use matrices, assess using the Integral Index of Connectivity (IIC), developed by Pascual-Hortal & Saura (2006).