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How can the ecosystem service approach provide insights for sustainable management of Portuguese estuaries?
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Os estuários são sistemas de transição entre ambientes dulçaquícolas e marinhos, onde a intrusão salina delimita a fronteira entre o ecossistema fluvial e o costeiro. Historicamente, os estuários têm um valor elevado para as comunidades humanas, oferecendo recursos como alimento (e.g., pesca) e lazer (e.g., desportos aquáticos). São ainda valorizados pela sua capacidade de proteção contra inundações e eventos extremos, e pelo sequestro de carbono. A riqueza em recursos estuarinos proporcionou o estabelecimento de comunidades junto a estes ecossistemas e o desenvolvimento de atividades comerciais, as quais, por sua vez, dinamizaram a evolução de muitos estuários para zonas portuárias. O conceito de Serviço do Ecossistema (SE) surgiu pela necessidade de compreender os usos dos recursos e funções naturais para o bem-estar humano. Deste modo, SE é definido como um serviço providenciado por um ecossistema, natural ou não, que impacta, direta ou indiretamente, o bem-estar humano. Infelizmente, o intenso uso dos estuários levou à transformação destes ecossistemas, sem que tivesse ocorrido uma eficaz adaptação na gestão e proteção dos mesmos, o que torna os estuários ainda mais vulneráveis a eventos naturais. A falta de reconhecimento do seu valor, apenas agravou a situação. Atualmente, a maioria dos modelos de governança não incluem os estuários. Apesar deste ser um assunto discutido habitualmente entre a comunidade científica, os estuários portugueses continuam sem proteção própria ou gestão integrada à escala de todo o ecossistema. O estuário do Sado (Setúbal, Portugal) é um dos casos mais vulneráveis, apesar de usufruir parcialmente do estatuto de Reserva Natural. É neste contexto que surge o presente estudo, que teve como principal objetivo realizar uma avaliação integrada dos SE do estuário do Sado. A longo prazo, pretende-se que este estudo possa contribuir com orientações para uma gestão sustentável do estuário mediante a aplicação de uma abordagem que analise a dinâmica ecológica, económica e social dos SE providenciados pelo estuário do Sado. Por conseguinte, foram definidos cinco objetivos específicos, que serão abordados em quatro capítulos complementares.
The increasing exploitation of estuaries has not been accompanied by a progress of effective management plans. This overarching aim of this study was to provide a comprehensive assessment of Ecosystem Services (ES) in the Sado estuary, ultimately offering guidelines for a sustainable management using an ES-based approach. Five specific objectives were addressed in four chapters. Initially, the legal framework for estuarine management in Portugal was reviewed and evaluated (Objective 1). Estuaries remain under-protected, highlighting the need for innovative governance approaches to increase ecosystem management. This chapter is the foundation for the following steps by proposing the use of new management approaches into the current governance system. For Objective 2, remote sensing tools were used to identify and map service providing units in intertidal zones of the Sado estuary. Based on this mapping, the potential supply of ES was assessed (Objective 3), along with stakeholder perceptions about ES supply and demand (Objective 4). Finally, the impacts of different management strategies and climate change on ES provision were evaluated using scenario modelling (Objective 5). Results indicate that the Sado estuary provides a total of 37 ES, in line with the potential capacity. However, stakeholders had difficulty in mapping ES regulating and demand. In line with the stakeholder challenge to map regulating services, modelling tools (InVEST models - Nutrient Delivery Ratio and Habitat Quality), were used to quantify and map water purification, a highly regulating ES provided by intertidal habitats. Agriculture and grazing fields were identified as the main nutrient exporters, while saltmarshes were the primary nutrient retainers and these were also the habitats in better condition according to the model simulations. Scenarios which modified nutrient input presented most significant differences in water quality compared to business-as-usual. The methodology presented can support future decision-making processes, by engaging directly with the stakeholders and transforming scientific outputs into actionable knowledge for estuarine governance
The increasing exploitation of estuaries has not been accompanied by a progress of effective management plans. This overarching aim of this study was to provide a comprehensive assessment of Ecosystem Services (ES) in the Sado estuary, ultimately offering guidelines for a sustainable management using an ES-based approach. Five specific objectives were addressed in four chapters. Initially, the legal framework for estuarine management in Portugal was reviewed and evaluated (Objective 1). Estuaries remain under-protected, highlighting the need for innovative governance approaches to increase ecosystem management. This chapter is the foundation for the following steps by proposing the use of new management approaches into the current governance system. For Objective 2, remote sensing tools were used to identify and map service providing units in intertidal zones of the Sado estuary. Based on this mapping, the potential supply of ES was assessed (Objective 3), along with stakeholder perceptions about ES supply and demand (Objective 4). Finally, the impacts of different management strategies and climate change on ES provision were evaluated using scenario modelling (Objective 5). Results indicate that the Sado estuary provides a total of 37 ES, in line with the potential capacity. However, stakeholders had difficulty in mapping ES regulating and demand. In line with the stakeholder challenge to map regulating services, modelling tools (InVEST models - Nutrient Delivery Ratio and Habitat Quality), were used to quantify and map water purification, a highly regulating ES provided by intertidal habitats. Agriculture and grazing fields were identified as the main nutrient exporters, while saltmarshes were the primary nutrient retainers and these were also the habitats in better condition according to the model simulations. Scenarios which modified nutrient input presented most significant differences in water quality compared to business-as-usual. The methodology presented can support future decision-making processes, by engaging directly with the stakeholders and transforming scientific outputs into actionable knowledge for estuarine governance
Descrição
Tese de doutoramento em Ciências do Mar, Universidade de Lisboa, Faculdade de Ciências, 2026.
Palavras-chave
Coastal and estuarine governance Intertidal habitats Participative methods GIS applications Transdisciplinary approaches Abordagens transdisciplinares Aplicações de ferramentas SIG Governança costeira e estuarina Habitats intertidais Métodos participativos