Management strategies for coastal ecosystems in the face of climate change and increasing human pressure

Tidal coastal wetlands face increasing threats from climate changes and anthropogenic pressures, resulting in ecosystem loss and heightened flooding risk, negatively impacting the quality of life in coastal communities. Where population relocation is not feasible, strengthening coastal defences becomes essential to preserve the functioning of human settlements. This thesis tackles the challenge of balancing coastal wetland preservation with ensuring the resilience of coastal communities against flooding, driven by rising sea levels and intensifying extreme events. These needs are often interdependent but can sometimes be mutually exclusive, requiring careful consideration and management. Using the flood-regulated Venice Lagoon, Italy, as a pilot case study, this research employs numerical modeling to explore the long-term implications of various flood management strategies. Fieldwork in the minimally human-affected Virginia Coast Reserve, USA, complements these findings, providing a comparative perspective on ecosystem resilience. The study focuses on four key objectives: (i) evaluating the morphological evolution of the Venice Lagoon under anthropogenically-regulated tidal water levels, (ii) investigating trade-offs in flood-regulation strategies for sustainable urban and ecological resilience, (iii) assessing the ecosystemic equilibrium under multiple-and-independent flood-protection measures in present and future scenarios, and (iv) analyzing the development of salt-marsh ecosystems in environments with minimal human impact, under accelerated sea-level rise. By integrating these findings, this thesis provides a framework for sustainable management of coastal cities and ecosystems globally, provided local geomorphology and morphodynamic processes are adequately considered.