Nature-based solutions (NBS) are actions that use natural processes in a resource efficient manner to solve societal challenges. The lack of supportive legislature, and financial, communication and social barriers complicate the process of NBS implementation. It is an urgent need to develop approaches to design and implement NBS that would act as drivers to overcome potential barriers and enhance the social acceptability of the project. The vision-based decision-making methodology and participatory process created in this study has been carried out in the Koiliaris Critical Zone Observatory in Crete to design erosion and flood protection NBS and restore the riparian forest. The methodology consists of four distinct steps as follows: i) develop a vision of the area, ii) conduct a baseline assessment study, iii) NBS design and co-design, and iv) procurement and implementation. The methodology overcame multiple barriers because of the effective stakeholder engagement and the vision “drove” the project and created the necessary consensus that is necessary to achieve the objective of converting privately owned prime agricultural land to riparian forest. It offers an exemplar of a functional ecosystem restoration project that protects the river in a sustainable way, improves its biodiversity and water quality and improves the quality of life and social cohesion.

Mediterranean ecosystems are in the spotlight of tourism activities, with the local populations trying to make the most of them, while in parallel, the stress signs, such as habitat and biodiversity degradation, increased pollution, or beach erosion, have begun to emerge. Furthermore, this combination of exotic and delicate qualities accompanied by excessive tourist flows leads to the imperative need for sustainable tourism development studies in these areas. In the current study, aiming to develop a new holistic framework for assessing Carrying Capacity in sensitive coastal ecosystems, a combined methodology was created and tested in Balos Lagoon, a Natura 2000 area in Western Crete. The method encompasses calculating different Carrying Capacity indicators, environmental quality measurements, visitors’ perceptions identification, and finally, a multicriteria analysis to capture the stakeholders’ and local community’s viewpoints. The combined methodologies identified vital issues, including overcrowding—Effective Carrying Capacity is exceeded by 1000 people per day during the peak season—tar residue pollution, microplastics, insufficient road infrastructure and excessive car numbers exceeding capacity. Stakeholder involvement was pivotal, prioritizing twelve proposed actions to address those issues. Notably, “frequent beach clean-ups,” targeting visual impacts, emerged as the most critical action, while parking reallocation and setting a maximum daily ferry limit were also highly ranked, promising solutions to alleviate overcrowding issues. The paper offers valuable insights for future research, emphasizing the need for continuous environmental monitoring, implementation of high-priority measures, and economic valuation of natural capital. Ultimately, this research contributes to the literature by presenting a pioneering methodology for holistic assessment and sustainable tourism development in Mediterranean sensitive coastal ecosystems.

The water ecosystem food (WEF) nexus duly acknowledges the complex interdependencies among water, ecosystems, and food production, underscoring nature based solutions (NBS) as an efficacious strategy for navigating these interconnections. In this research, four different NBS (terraces, riparian forest, livestock management and agro ecological practices) were assessed in terms of their impact to WEF nexus. The Karst-SWAT and the one-dimensional integrated critical zone (1D-ICZ) models were used to simulate the impact of NBS on water quantity and quality as well as on soil ecosystem services of Koiliaris River Basin, which serves as an illustrative example of a basin that has experienced severe soil and biodiversity degradation. The Karst-SWAT model showed that a combination of NBS of terraces and riparian forest can reduce soil erosion and the sediment load by 97%. The 1D-ICZ model successfully simulated the soil-plant-water system and showed that agro ecological practices affect biomass production, carbon and nutrient sequestration, soil structure and geochemistry.