Beach litter and woody-debris colonizers on the Atlantico department Caribbean coastline, Colombia

Highlights: • Floating marine litter doubles or even triples the dispersal potential of marine organisms. • Along the Atlantico Department coastline (Colombia) average abundance of refuse is 2.9 items m⁻¹. • Some marine species were found using litter and woody debris as a substrate for potential rafting and dispersal. • Three taxonomic groups were found: Bryozoans, barnacles, and polychaetes. • Primary source of litter corresponds to litter transported by rivers, together with human activities related to beach use. - Abstract: Some marine invertebrates can inhabit floating substrates, and raft over long distances, becoming a significant environmental problem in terms of alien species and habitat disruption. On the Atlantico Department beaches (Colombia) woody debris and plastic litter dominate (86%) the types of refuse on the beaches with their densities ranging from 0.82–1.72 items m⁻¹. Such litter and woody debris generate the optimal conditions for floating colonizers. In this work, 26 beaches were surveyed, and 16 of them (62%) were found to have marine fauna using litter and woody debris as a substrate for potential rafting and dispersal. Serpulidae polychaete tubes, goose barnacles Lepas (Anatifa) anserifera Linnaeus, 1767, and the bryozoans Arbopercula tenella (Hincks, 1880), Arbopercula angulata (Levinsen, 1909), plus three unidentified species were found colonizing woody debris, seeds, plastic and glass bottles. These findings of woody debris and litter facilitating the arrival and dispersal of non-native species on this coast, demonstrate that preventive management of such refuse in coastal habitats goes beyond simply preserving coastal esthetics.