Coastal wetlands food provisioning ecosystem services under a changing climate

Climate change (CC) is projected to affect coastal wetlands in multiple ways, altering their physical structure, community composition, ecological processes, and functions. However, society and ecosystems are deeply interconnected, since humans depend on ecosystems to live, while at the same time shaping and transforming ecosystems and their dynamics. The concept of socio-ecological systems (SESs), captures this complex interdependence, emphasizing that social and ecological systems cannot be fully understood separately. CC-induced modification of ecological processes and social system could indeed generate cascading and non-linear effects on both components, posing severe threats to SESs ability in providing Ecosystem Services (ESs). In this challenging procedural context, the main goal of this my PhD project was to offer an entry point for the exploration of CC impacts on socio-ecological systems, by integrating and systematizing existing data, and generating new empirical evidence through mixed methodologies, both quantitative and qualitative. Starting from a narrative literature review, I focused on what is known (and what is missing) about CC and coastal wetlands ESs. While this chapter confirms the growing interest of the scientific community towards this topic, I also highlight past and current methodological and knowledge gaps that still hamper our ability to fully understand and anticipate future CC impacts on SESs. Then, taking Sardinia coastal lagoons and food provisioning ESs as case study I conducted two complementary assessments to evaluate CC vulnerability of SESs. Notably, I explored the vulnerability of the ecological component, with a focus on those characteristics involved in the provisioning of the ESs that determine ecosystem propensity or predisposition to be adversely affected. Whit this study I contributed to fill a gap in the European context by scaling down existing vulnerability assessments to the specificity of the Sardinian context, emphasising that ecological vulnerability can be unevenly distributed in space, and highlighting the importance of conducting fine-scale regional scale assessment to identify where (and why) management intervention should be targeted. Thus, by adopting a deductive-inductive mixed methodology, I explored the characteristics of the social elements of the SESs involved in the provisioning of the ESs that determine their propensity or predisposition to be adversely affected by CC, encompassing related concepts such as social sensitivity and lack of capacity. I also identified barriers and enablers toward adaptation, ultimately contributing to the broader debate on socio-ecological vulnerability in coastal lagoon small-scale fisheries with a SES lens, providing a first case study of this kind in Sardinian lagoons. Finally, to evaluate how and if existing knowledge can be incorporated in emerging ecosystem accounting frameworks, I explored the feasibility of compiling ecosystem accounts for Sardinia according to the System of Environmental-Economic Accounting - Ecosystem Accounting (SEEA EA), a recognized international statistical standard, using available data sources. While describing the potential of ecosystem accounting to inform cross-sectoral management and policy decisions, also considering the ongoing threats posed by CC, the availability, the choice of indicators and the data uncertainty handling played a central role in my study, potentially affecting the full operationalization of the accounts at subnational scale in the near future, especially in effectively tracking ecosystem condition and their services over time. Though aware that the case studies included here represent only a few pieces of the complex mosaic of SESs, my thesis has put light on aspects which, while relevant at first instances only at a regional scale, can nonetheless contribute to support advancing in future implementations of local-based CC adaptation strategies.