A semiquantitative model using the software Mental Modeler was developed for maërl beds in the Western Mediterranean. The conceptual model represents the multiple interaction between environmental and human factors happening in a maërl bed system, the key component of our model. These habitats are composed of species of coralline algae, which are found alive or dead as unattached nodules that cover large areas on the seafloor, also individually known as rhodoliths. Coralline algae are ecosystem engineers and hotspots of marine life occurring worldwide. Maërl beds provide a wide variety of ecosystem services such as nursery or carbon sequestration. Therefore, they are considered habitats with a remarkable conservation value, included in the European Habitats Directive (92/43/EEC). However, there are still human activities that threaten their ecological integrity such as bottom trawling, potentially increasing their vulnerability to climate change. The important components of the model and their relationships were defined based on literature review, expert knowledge and pre-processed quantitative data from Mediterranean maërl beds. Each component belonged to one of the following classifications: environmental drivers i.e., hydrodynamics; ecosystem services i.e., life-cycle maintenance; ecosystem components i.e., invertebrates and fish diversity; and impacts i.e., warming and fishing. We ran “what if” scenarios to explore the potential response of maërl beds, and its ecosystem services, under a range of projected human impacts and climate change scenarios

ASLO Aquatic Sciences Meeting, Resilience and Recovery in Aquatic Systems, 4-9 June 2023, Palma de Mallorca, Spain