Modelling approaches support decision making by first assessing the interplay between the environment, human influence, biodiversity and ecosystem services, and then generating scenario projections of alternative management actions or environmental changes relevant to the aquatic ecosystem.

The AQUACROSS project has assessed modelling approaches in selected AQUACROSS case studies and beyond. For a first analysis, the relevant linkages can be explored with a qualitative model, the linkage framework. The proposed spatially explicit modelling framework goes beyond and supports the identification of critical areas for allocating particular management actions.

Useful tools to approximate biodiversity and indicate possible hotspots are Species Distribution Models (SDMs) that use species geographic occurrences and environmental factors at those locations to simulate the range-wide potential habitat suitability across a study area. Ecosystem services can be analysed with the ARtificial Intelligence for Ecosystem Services (ARIES). Both the predictions of biodiversity and ecosystem services are then used to spatially prioritise different management zones. The modelling outputs include maps which allow the identification of critical areas for allocating particular management actions and enable stakeholders to visualise potential outcomes of scenarios. It further allows assessing trade-offs between conservation of biodiversity and use of ecosystem services, satisfying different stakeholder demands.

General challenges related to modelling are e.g. data availability, ensuring the connectivity within and between ecosystems, the availability and definition of scenarios, socio-economic issues, and stakeholder involvement. Challenges when applying the spatial prioritisation approach are related to setting “adequate targets”, such as a proportion of the total population of a species to be protected or the proportion of the delivered ESS to be used, or to consider spillover effects and connectedness. Further, only a limited number of management scenarios can be analysed, and cost information to analyse cost-effectiveness is often rudimentary.

Modelling in the AQUACROSS case studies tackled key issues of ecosystem-based management such as taking an interdisciplinary approach, considering societal choices, aiming at ecological integrity and biodiversity, or considering ecosystem connection. They employed well known and robust modelling approaches in a coherent framework to analyse both areas for conservation of aquatic biodiversity and different ecosystem services.

For example, the AQUACROSS modelling approaches yielded the following key outcomes: Modelling within the AQUACROSS Andalusia and Morocco case study showed higher probability of conflicts between conservation and exploitation goals in freshwater areas than in the marine and coastal areas. Modelling within the AQUACROSS Danube case study supports strategic planning of river-floodplain segments for conservation and restoration. Modelling within the AQUACROSS Aveiro case study relied on substantial stakeholder involvement for framing the baseline condition, formulating objectives, screening measures and instruments, the foreseen management measures and ecosystem services valuation.

The full report on Assessing Modelling Approaches in Selected AQUACROSS Case Studies and its Executive Summary are available online.