The water-energy-food-ecosystems (WEFE) Nexus has gained recognition as an innovative approach for analysing the interconnectedness of global resource systems and achieving sustainability goals. In the Mediterranean, where water scarcity, climate change, and ecosystem degradation pose significant challenges, implementing an integrated WEFE Nexus approach is crucial. We conducted a comprehensive review of scientific literature through the lenses of Nexus ‘ideas’, ‘relationship’ and ‘practices’. A total of 142 research articles were selected and characterized in terms of WEFE interlinkages being investigated, explored topics, methods and scales of analysis, and contexts of operationalization. We found that water-energy interdependences dominate WEFE Nexus research in the Mediterranean, driven by the large presence of energy-intensive water abstraction and distribution systems to meet drinking and irrigation water demands. At the same time, the expansion of the Nexus approach to additional components is only partial, mostly focusing on assessing impacts on the physical environment and climate, without capturing feedback dynamics. Geographically, Nexus research in the Mediterranean is primarily conducted in isolated case studies, with few large scale assessments developed at the entire Mediterranean scale, and with some countries not yet represented, in particular the Western Balkans. Although WEFE Nexus research in the Mediterranean is recognizing the importance of transdisciplinarity moving beyond biophysical assessments to encompass societal and governance dynamics, further research is needed on understanding the economic implications of WEFE Nexus interactions. To advance Nexus implementation in the region, sustainable technology, and natural resources management, which are key fields of WEFE Nexus research operationalization, would benefit from harmonization in their design objectives. This would enable a more comprehensive and coherent approach towards achieving water, food, and energy security while preserving the environment in the Mediterranean region.

This paper aims to analyze the scientific evolution and research trends concerning the water–energy–food (WEF) nexus, as well as its development within scientific databases. To achieve this, a bibliometric analysis has been conducted using publications sourced from Scopus and Web of science databases. This study examined key aspects such as primary journals, prominent authors, affiliated institutions, countries of origin, subject areas, and notable keywords. Furthermore, there is a dedicated section that delves into research and innovation gaps within publications related to the WEF nexus. Results reveal that research on the WEF nexus has experienced exponential growth over the past decade, with the majority of publications emerging between 2017 and 2023. The United States leads in this field, with engineering and environmental science being the predominant research categories, with Spain and Italy being the prominent countries in Europe. The WEF nexus concept in the agriculture sector is notably underdeveloped, particularly in its ties with the Sustainable Development Goals and the science–policy–society interface. The study stresses the importance of integrating health considerations into the WEF Nexus to understand the interconnections and their implications on public health, thereby enriching the Nexus approach with a critical dimension of human well-being. This situation underscores the urgent need to create a nexus community that bridges science and practice, and to incorporate this specialized discipline into university curricula.

The paper investigates the effects of climate change on riverine ecosystems in the Upper Arno River basin, adopting a hybrid methodology relating the changes in streamflow to its related water ecosystem services. Twenty hydrological models were run using the Soil and Water Assessment Tool (SWAT), under their respective climate model and emission scenario. The streamflow variable obtained was analysed according to the method of Indicators of Hydrologic Alteration (IHA). The development of spatial maps of IHA allowed us to represent the spatial of the results according to the three river subbasins studied, with a focus on the presence of hotspots. Using IHA allowed to capture of the streamflow quantity and dynamics, through groups of magnitude, timing and rates, where the potential effect could be then linked to the concept of water ecosystem services. Finally, the results obtained were presented as a proxy that can be integrated into the existing Driver, Pressure, State, Impact, Response (DPSIR) management framework to eventually move towards an ecosystem‐based management methodology. The main results, induced from the Mann–Kendall trend analysis of the IHA, suggested that provisioning and regulating services are to be affected by climate change where the quantity of flows shows a decreasing trend under several emission scenarios, in addition to an intensification of the extreme events. This shift is accompanied by a change in the dynamics of flow, which holds the potential of affecting habitat suitability. With the emergence of studies directed towards ecosystem‐based management, the study refers to well‐established hydrological modelling to evaluate climate change as a driver and provide screening results to ensure a proactive response planning that converges with the idea of ecosystems.

Over the last few years, the Water-Energy-Food (WEF) Nexus has been brought forward by scientists as a novel way of analysing the interconnectedness of global resources systems, and by policy makers as an approach to achieving water, food and energy security while preserving the environment. Implementing such an integrated thinking is crucial for the Mediterranean, a region characterised by increasing demand for food and energy, and vulnerable to water scarcity, impact of climate change and degradation of natural ecosystems. Through an integrative review of scientific literature, we examined the evolution of Nexus research in the Mediterranean in terms of critical interlinkages being investigated, explored topics, methods and scales of analysis, and context of operationalizations. The 136 reviewed articles revealed that (a) water-energy interlinkages dominates Nexus research in the Mediterranean, driven by the need of satisfying water demands for drinking and irrigation through energy-intensive water resources; (b) the expansion of Nexus thinking to additional components is mostly limited to assessing the impact of Nexus sectors on the physical environment and the climate, without capturing feedback dynamics; (c) there are only few Nexus studies working at the entire Mediterranean scale which would provide a much needed contextual setting to the impact of isolated case studies; (d) there is promising evidence that Nexus research in the Mediterranean is going beyond the biophysical dimension to encompass socio-economic interactions and governance aspects; yet, (e) their analysis often remain segregated in silos because of a limited integration of methods across disciplines; (f) Sustainable Technology and Natural Resources Management are the key drivers of Nexus research operationalization and would benefit from an harmonisation to coherently advance Nexus implementation in the Mediterranean region. This review concludes that Nexus research in the Mediterranean would benefit from an integration of the knowledge developed so far in multi-scale, multi-sector, and multi-dimensional frameworks, which would be capable of supporting technological, socio-economic and governance interventions.

Summarizing the various dimensions of the Water-Energy-Food-Ecosystem (WEFE) Nexus and articulating their interconnections through indicators can improve the understanding of the Nexus among both experts and stakeholders without specialized knowledge, supporting the transition towards implementing a WEFE Nexus approach for effective management of socio-ecological systems. As part of the EU PRIMA-funded project NEXUS-NESS, a participatory approach has been devised for identifying indicators related to the WEFE Nexus. The project's objective is to collaboratively develop WEFE Nexus management strategies within four Living Labs, designated as Nexus Ecosystem Labs (NELs), situated in distinct Mediterranean countries (namely, Egypt, Italy, Spain, and Tunisia). To achieve this, the concept of Responsible Research and Innovation (RRI) has been implemented through the RRI Roadmap (The RRI Roadmap©™ is under the ownership of XPRO Consulting Limited) methodology to establish a stakeholders’ participatory and interactive process. This involves active engagement between societal stakeholders and scientists, fostering knowledge-sharing and co-defining the indicators used to represent the WEFE Nexus within the NELs. Specifically, the work done has led to the formulation of a comprehensive inventory of WEFE Nexus indicators, applicable across all NELs. Additionally, a simplified representation has been developed to provide a preliminary assessment of the Nexus within the NELs under current conditions and future scenarios. Subsequently, a matrix approach has been devised to systematically map and evaluate all interconnections within the WEFE Nexus within a given NEL, utilizing indicators tailored to the specific needs of that NEL and its stakeholders.These indicators will play a crucial role in assessing the advantages and trade-offs associated with proposed solutions to the main Nexus-related challenges identified within the NEL. Furthermore, they will support the cost-benefit analysis, serving as a pivotal element in the identification of the most suitable WEFE Nexus-based management strategies. The methodology can be applied to any waterbody that wishes to develop a WEFE Nexus management strategy and achieve ownership and willingness for change by the waterbody’s stakeholders.