Temporal and spatial distribution patterns of beach litter on a Mediterranean coastal dune: A case study from Sardinia, Italy

Beach litter is one of the most widespread and persistent forms of pollution affecting coastal environments globally. In this study, we aim to analyse the temporal and spatial distribution patterns of beach litter in a Mediterranean coastal dune system, evaluating how seasonal dynamics and habitat characteristics influence the accumulation and distribution of this anthropogenic component. To this end, nine transects were randomly positioned in the study area, perpendicular to the shoreline. Within each transect, all consecutive plots (each measuring 4 m2) were analysed, and monthly surveys were carried out for a whole year. Over the entire monitoring period, a total of 21,904 items were recorded. The results obtained highlight a marked variability in the distribution of litter along the beach. A seasonal trend was observed with a peak of accumulation in the winter and spring seasons. Specifically, the months with the highest accumulation were January, March, April and December. Furthermore, the accumulation was influenced by psammophilous plant species and communities (habitat) type, with the EU Habitat 1210 showing a significantly higher amount of beach litter (12.14 +/- 1.95) compared to the other habitats. Moreover, our study area has been classified as extremely dirty based on the Clean-Coast index (total CCI = 31.92), with an average litter density of 1.60 items/m2, which exceeds the global average density. These results underline the importance of adopting targeted waste management interventions on beaches, which consider both temporal and spatial variables, to reduce the accumulation of this component and limit its impact on coastal ecosystems.