A systematic map of syntheses on anthropogenic noise impacts on wildlife: evidence gaps, policy attention, and quality appraisal

As systematic reviews on the effects of anthropogenic noise on wildlife increasingly inform policy, a critical evaluation of this secondary evidence is essential. We assessed the scope, quality, and policy attention of existing syntheses in this field. Following a preregistered protocol, we conducted a systematic search in Scopus, Web of Science, and Google Scholar, identifying 50 syntheses (systematic reviews, maps, and meta-analyses). We included all 50 syntheses in the systematic map, critical appraisal, and policy-attention analysis, and found that 23 had received policy citations. We included 47 syntheses in the bibliometric analysis. Syntheses were published between 2008 and 2025, with a focus on behavioural, physiological, and communication outcomes in wildlife. Most examined transportation and energy-related noise and reviewed evidence from marine, followed by terrestrial ecosystems. We found critical gaps in taxonomic coverage, with notable underrepresentation of invertebrates, amphibians, and reptiles. Most syntheses were led by researchers from the UK, Canada, and the USA, with limited participation from non-English-speaking countries. Almost half were cited in policy documents, mainly government and regulatory submissions. Syntheses on marine environments received the most policy citations, while those on urban noise received the least. There was no significant difference in quality scores between policy-cited and non-cited syntheses, and most were rated low due to methodological and reporting shortcomings. Our findings highlight the need to fill synthesis gaps and improve methodological transparency to strengthen the evidence base for policy decisions on anthropogenic noise.