Litter and microplastic contamination in bearded vultures (Gypaetus barbatus) from the Central Italian Alps: a preliminary study

The contamination of terrestrial ecosystems by discarded plastic has gained increasing attention in the last decade. However, its extent and impact on remote, high-altitude habitats remain insufficiently explored. Based on evidence of anthropogenic materials in bearded vulture (Gypaetus barbatus) nests at high altitudes (above 2000 m a.s.l.) in the Stelvio National Park (Central Italian Alps), we monitored two nests from 2016 to 2020, collecting anthropogenic nest materials, faecal samples, and food remains to assess plastic contamination and diet. In total, 21 macro-fragments were found and ATR-FTIR analysis showed that most were bio-plastic bags, while two consisted of synthetic plastic films (EVA). Additionally, we detected 15 potential anthropogenic micro-materials in 15 out of the 50 faecal pellets analysed. µ-FTIR analysis allowed to identify seven cellulose-based, man-made fibres, while one fragment was identified as PVC. On average, we found 0.3 anthropogenic micro-items per pellet, corresponding to 0.12 micro-items per gram of faeces. No significant difference was recorded in the frequency of occurrence of macro- and micro-materials when comparing the two territories. Four mammal species-chamois (Rupicapra rupicapra), alpine ibex (Capra ibex), marmot (Marmota marmota), and sheep (Ovis aries)-formed the bulk of bearded vulture diet in both territories. Overall, this study points out that even species living in remote mountain areas may be impacted by plastic litter and the need for further investigation and the development of more effective policies to address pollution in sensitive areas.