Abstract
The present thesis is targeted to address the need for sustainable management of coastal lagoons, focusing on the Nestos Delta lagoons in Greece, where environmental significance coexists with anthropogenic pressures. The thesis is structured into six chapters, beginning with an overview of coastal lagoons characteristics, importance, and ecosystem management challenges. The study identifies the pressures in the Nestos Delta area, quantifies the ecosystem services (ES) provided by the lagoons, implements the DPSER (Drivers-Pressures-State-Ecosystem Services-Responses) model, and maps historical Land Use/Land Changes (LULC). Additionally, it quantifies stakeholder perception towards management practices using intuitionistic fuzzy sets (IFS), and selects the most effective measures for sustainable management. The framework proposed is based on ecohydrology and participatory management principles, ensuring the active involvement of all relevant stakeholders. Coastal lagoons are unique eco ...
The present thesis is targeted to address the need for sustainable management of coastal lagoons, focusing on the Nestos Delta lagoons in Greece, where environmental significance coexists with anthropogenic pressures. The thesis is structured into six chapters, beginning with an overview of coastal lagoons characteristics, importance, and ecosystem management challenges. The study identifies the pressures in the Nestos Delta area, quantifies the ecosystem services (ES) provided by the lagoons, implements the DPSER (Drivers-Pressures-State-Ecosystem Services-Responses) model, and maps historical Land Use/Land Changes (LULC). Additionally, it quantifies stakeholder perception towards management practices using intuitionistic fuzzy sets (IFS), and selects the most effective measures for sustainable management. The framework proposed is based on ecohydrology and participatory management principles, ensuring the active involvement of all relevant stakeholders. Coastal lagoons are unique ecosystems of high ecological and economic importance. Due to their special geomorphology and hydrology, they are biodiversity hotspots, and at the same time support anthropogenic activities, such as fisheries and tourism. The literature review conducted in the first chapter of the present dissertation, reveals that anthropogenic activities, along with climate change increase the vulnerability of coastal lagoons and therefore there is imperative need for their sustainable management. Even though several environmental protection frameworks and initiatives have been developed, especially in EU, to improve these systems’ ecological status, there still lot to be done to achieve their ecological and economic sustainability. The study area selected for this thesis is the Nestos Delta lagoons of Vassova, Erateino, Agiasma and Keramoti located on the western bank of the Delta. The study area was selected, due to the recorded high biodiversity, the significant economic value, the environmental protection legislation, and the lack of ES and LULC oriented research. The area of Nestos Delta has been subjected to significant human interventions over the last 80 years, such as the river’s embankment, an increase in the population of settlements, the intensification of agriculture, and the tourism development. The Ecosystem Services (ES) are defined as the direct or indirect benefits that human societies derive from the ecosystems and include provisioning, regulating, and cultural services. This environmental concept has gained popularity, and is increasingly accepted and embedded in policy at local, national, and global scales, recognizing the crucial role of natural systems in supporting human well-being. Mapping ES and assessing them using proper indicators is crucial for addressing the vulnerability of the system and develop a management plan to achieve sustainability. The concept of sustainability is also described by the UN, which posed the Sustainable Development Goals (SDG), developing suitable indicators for their assessment. The integration of ES and SDG approaches in water system management is essential for advancing an environmental approach to development plans and ensuring the equitable and efficient use of water resources while protecting ecosystems. The selection and quantification of the proper indicators of ES and SDG is required to develop policies related to water systems management. Thus in the third chapter of this thesis, a list of correlated indicators has been developed for the study area, consulting a list proposed by CICES (Common International Classification of Ecosystem Services) for ES indicators, while the OECD (Organisation for Economic Cooperation and Development) Core indicators framework has been used for the Ecological Sustainability Indicators (ESI). This Dissertation is the first description of ES provided by ND lagoons, as well as the first report of values of indicators of ES coupled with ESI. The selection of the indicators was based on: a) economic and social outputs, b) the Water Framework Directive (WFD) implementation, c) the Habitat Directive (92/43/EU), d) their relation to the eutrophication process and e) the availability of data. For the assessment of the selected indicators samplings took place and furthermore data were provided by stakeholders. The results of the chapter indicate that the integration and simultaneous assessment of ES and Ecological Sustainability Indicators is feasible and assists policy makers to track the needs of the system to achieve sustainability. The research community, especially in the EU, has made great efforts to provide tools to support the implementation of policy instruments for sustainability. In this context, the DPSIR (Drivers–Pressures–State–Impact–Response) model has been used as an analytical framework for the identification of pressures and impacts in the context of the WFD, as it is considered an effective tool for both society and policy makers in terms of water systems management. Since the importance of ES is widely accepted, there is much scientific drive to embrace the ES based approach, into the DPSIR tool. Based on the linking of these processes in chapter three is also presented an integration of the DPSIR model with the ES concept. According to the DPSER approach described in the present dissertation, the major driving forces leading to pressures were mainly the agriculture and the urbanization, while the livestock and the industry were also recorded. The pressures exerted by the recorded drivers, are affecting the chemical and ecological status of the lagoons, hindering their sustainability. The deterioration of the systems’ status affects ES both directly and indirectly with the regulating ES being the most impacted. The findings presented in chapter three indicate that several management measures need to be implemented, applying an multi-disciplined approach. The urbanization and land claim trends for intensifying agriculture have to modifications in the lifestyle and human needs, resulting in land use/land cover (LULC) changes, causing several natural environment alterations. Mapping LULC changes and its impacts on ES is crucial for decision making processes in meeting the goals of nature conservation and sustainability. To support sustainable management of the study site, a historical (80-year) assessment was conducted, using aerial photos and satellite images. Through photo-interpretation of these historical images, the mapping of the lagoon’s land uses was conducted utilizing Corine Land Cover classification. Moreover, this process provided valuable insights into the drivers and trends of these changes. The result show that until 1960, water-related Biomes were affected the most, in favor of agricultural (Nestos River embankment) and urban ones, but anthropogenic activities development rate reduced after land reclamation. The inclusion of the area in the Natura 2000 network and its designation as a National Park, have protected the coastal lagoons from the effects of the rapid development of the last 20 years. In addition, it is important that this system protection legislation has helped to increase the economic value of cultural ES, while not significantly affecting the provisioning services. One of the objectives of the fourth chapter, was the economic valuation of the system and the ES provided and the monetary assessment of the effects of the identified LULC on the systems’ value. This was performed, using widely accepted methodology that allows the comparison between similar systems in a global range. During the study period, the LULC changes have resulted in a cumulative loss exceeding USD 30 million. The results strongly indicate that legislative protection and integrated management of priority habitats is vital to achieve the highest ES values. Facing the threats that arise from anthropogenic activities and climate change is the main challenge of management in coastal lagoons. Management strategies focusing solely on ecological elements’ improvement have not yielded the desired outcomes, as they often neglect the needs and perspectives of stakeholders utilizing these systems. The participatory approach promotes stakeholder engagement and awareness, aiming to develop sustainable and effective management strategies. In an effort to contribute to the preservation and sustainable use of coastal lagoons, in the fifth chapter a participatory approach has been applied, which is a comprehensive method to addressing complex environmental challenges. This approach promotes the stakeholders’ involvement and ensures the representation of the conflicting interests in the study area. The complex nature of the ecosystem, along with the plurality of stakeholders’ opinion underscored the necessity for employing a multi-criteria methodology. Furthermore in order to capture the inherent uncertainty in stakeholder opinions, a fuzzy analysis using intuitionistic fuzzy sets (IFS) has been implemented. By using this method, stakeholder perspectives were quantified considering multiple criteria and an intuitionistic distance-based method was applied to rank management alternatives. The findings presented in this chapter indicate that not only the scientific community, but also the stakeholders of Nestos Delta lagoons identify agriculture as a critical pressure of the system and thus they favor management alternatives to mitigate these effects. Additionally, this chapter illustrates that the integration of the participatory approach combined with IFS can facilitate building agreement among different stakeholders and ultimately support decision-making and achieve sustainability. Overall, this dissertation contributes to the understanding of ES in Greek coastal lagoons, illustrating that improved ES correlate with sustainable practices and offer valuable insights for future conservation efforts. Additionally, it emphasizes the importance of interdisciplinary approaches (ecological, social and economic), stakeholder engagement, and inclusive decision-making in managing Mediterranean coastal lagoons to address the complex challenges. Summarizing, the thesis, through the methodologies it has developed and applied, (mapping and assessing ES, identifying historical LULC and monetary valuating of their effects, application of an integrated participatory approach with IFS) describes the necessary steps for developing a holistic approach and a comprehensive, multi-disciplined management plan that improves environmental health and society's welfare. Future research directions include addressing of the knowledge gap in lagoon hydrology, understanding of biodiversity in carbon sequestration, and widely apply the proposed framework for informed decision-making through stakeholder engagement to ensure sustainable management of these vital ecosystems.
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