The macrophytes stranded on the beach, also known as wrack can provide habitat and food to beach-dwelling macrofauna and seabirds, contribute to carbon and nutrient cycling and protect from coastal erosion, when accumulations are large and compact. In the Mediterranean Sea, beach wrack is largely composed of endemic seagrass Posidonia oceanica leaves and rhizome fragments, often mixed with woody debris. The aim of this study is to investigate how macrofauna varies in relation to wrack accumulation on northwestern Mediterranean beaches. We expect that greater wrack cover may be associated with higher macrofaunal abundance and diversity. 

During spring 2026, a sampling campaign was carried out on twelve beaches within three locations (Tuscany, eastern and western Liguria) to encompass a range of environmental conditions. On each beach we sampled along three transects high and low on the shore. Macrofauna was collected using five replicated pit traps per transect and height on the beach, deployed overnight. Wrack cover was quantified visually (%) using five 50 × 50 cm quadrats around each pit trap. The study is part of the Interreg MARITIMO project AMMIRARE, which aims to enhance the resilience of Mediterranean beach ecosystems to climate change through the management of P. oceanica accumulation as a nature-based solution.  

We will present the preliminary results of this study and discuss new insights into the ecological role of wrack and its relevance for sustainable coastal management.