Difference between invasive alien and native vegetation in trapping beach litter: A focus on a typical sandy beach of W-Mediterranean Basin

Abstract

Beach litter is one of the most pervasive pollution issues in coastal environments worldwide. In this study, we aim to assess the amount and distribution of beach litter on Porto Paglia beach, its entrapment across psammophilous habitats, and whether the invasive Carpobrotus acinaciformis (L.) L.Bolus plays a different role in trapping litter than native vegetation. To this end, two seasonal samplings (in spring and autumn) were conducted using a paired sampling method that considers plots in all coastal habitats with and without C. acinaciformis. Our results confirm that the main beach litter category is plastic, and that its distribution varies across habitats: the white dune seems to play a greater role in trapping and filtering beach litter, reducing its amount in the backdune. A correlation was found between the Naturalness index (N) and the beach litter amount, supporting the finding that invaded habitats trap beach litter better than native ones.

Keywords: Beach litter distribution; Coastal habitats; Invasive plant species; Naturalness; Plastic items; Sardinia.