A process-based model for multiple ecosystem services in the Venice lagoon under climate change and demographic forcings

Understanding the dynamics and trade-offs of ecosystem services (ESs) represents a crucial step towards a more sustainable management of coastal lagoons. Nonetheless, within ESs modelling, process-based dynamic models had a confined development. This work presents a non-spatial process-based model that represents the dynamics of twelve ESs in the Venice lagoon, grounded in the social-ecological system framework. ESs emerge from the interactions among habitats, fauna, and actors, represented as state variables through a system of ordinary differential equations, forced by climatic and socio-demographic trends. A comprehensive set of data on habitats, fauna, and ESs was considered to parameterise the model, and a numerical simulation covering the years 2000-2080 was performed. Parameters sensitivity was explored through the Morris method. Simulations reveal long-term trends in ESs and state variables, showing a marked long-term decline of lifecycle maintenance and fishing activities, driven by the negative trends of intertidal habitats and fauna. Habitat loss, restoration, and lagoon high-tide regulation influence the lifecycle maintenance ESs, shaping faunal dynamics; nonetheless, the decline in provisioning ESs is also related to the trend in actors, including artisanal and recreational fishers. Simulation outputs and sensitivity analysis showed that the model is capable of representing contrasting feedbacks among different cultural ESs, habitat dynamics and fauna, which are subjected to the exogenous trends in tourists and residents, highlighting leverage points for lagoon management. Comparison with historical data and sensitivity patterns provides guidance for future model development and applications to policy scenarios.