Riparian areas, the transitional areas between terrestrial and aquatic ecosystems, are considered cornerstones within the landscape due to their potential contribution to ecosystem service provision. However, they have been subject to a multitude of disturbances, mainly as a consequence of anthropogenic activities such as land use changes, pollution or intense grazing. Restoring and enhancing the wellbeing of these systems have become a priority for progressing towards a sustainable use of our resources and maximizing the delivery of ecosystem services. The overall thesis aims are to critically evaluate different methodologies to delineate riparian areas, especially considering their subsequent use for management purposes and ascertain their relative contribution to the provision of ecosystem services at the local and landscape scale. First, I started by critically evaluating the relative accuracy of different riparian delineation approaches and the impact of data quality and data types on predictions of riparian typologies. I concluded that different delineation methods greatly influenced the prediction of riparian typologies and the potential ecosystem service provided. Therefore, aspects such as economic viability of the buffer or their inclusion within priority habitats should be considered. In subsequent studies, I explored the contribution of riparian areas to deliver a broad range of ecological processes related to water quality enhancement and how riparian vegetation across different habitat types contributed to the provision of shade. My findings revealed that habitat type was the main driver explaining riparian soil physicochemical variability and that riparian function can be largely predicted from neighbouring land use/soil type. Additionally, I identified through a GIS approach that watercourse shading was maximal in afforested areas. Subsequent studies focused on specific regulating services (e.g. C sequestration and N cycling) in riparian areas in semi-natural ecosystems at a finer scale. Firstly, we critically evaluated the influence of five factors (i.e. nutrient stoichiometry, substrate quality and quantity, variations in microbial community due to proximity to the river and soil depth) on C mineralization rates. Differences in the immediate and long-term response of C mineralization suggested different microbial C use efficiency strategies through the soil profile. However, the influence of riparian area vs. nonriparian was minimal. The next experiment focused on denitrification in riparian wetlands with the aim to elucidate the effect of environmental factors, vegetation and microbial communities and N cycling gene abundance, regulating denitrification activity. This identified major changes in soil physicochemical properties, microbial community abundance and structure across the riparian transect, most likely influenced by the hydrology of the site. Additionally, I identified areas close to the river as a potential source of N2O emission whereas distal areas could become a sink. The last chapter aimed to assess the legal framework affecting riparian areas and identify knowledge gaps in current research. Results showed that the legislation concerning riparian areas was highly fragmented and often contained untargeted measures. In contrast, research tended to focus on specific ecosystem functions (e.g. N removal) in agricultural systems. Our study illustrated that past and current research lacks a multi-ecosystem service based approach that legislative policies promote. This mismatch is due to the complexity of undertaking holistic research and the lack of resources and economic support. This research provides a more detailed understanding of riparian ecosystem functioning. The thesis provides essential information that allows location of where, when and how we might expect the provision of pivotal ecosystem services in riparian areas, especially if the ultimate management goal is their protection, reinstatement of their pristine state or enhancing their resilience in a continuously changing climate.