Waders in a sea of debris: a global overview

Abstract

The impact of plastic pollution on ecosystems and marine fauna is well documented, although research into its effects on waders (also known as shorebirds) remains limited. Given that waders are exposed to coastal marine litter, this exposure could be a significant factor in the decline of their populations. This study aims to assess the global distribution of plastic ingestion in waders and investigate regional differences in their exposure. Our analysis included 30 studies, examining 316 digestive tracts and 1114 faecal samples. Only four studies analysed plastic in wader nests or entanglements. Eastern Asia exhibited the highest prevalence of plastic ingestion in waders, although no significant differences were detected among coastal regions. Descriptive patterns suggest that this trend may be influenced by intensive industrial activity, high population density, and pollution along migratory flyways. Southern Asia had the highest prevalence of plastics in faecal samples. No statistically significant differences were observed across wader families; however, descriptive results indicated elevated ingestion frequencies in Haematopodidae and Scolopacidae, while Recurvirostridae and Haematopodidae tended to show higher plastic prevalence in faecal samples. This study highlights the need for standardised sampling protocols and continued research on the effects of plastic on wader populations, which could contribute to their conservation.