The ability of Google Scholar to find included articles from six published systematic reviews.

1 For those articles not found using Google Scholar, Web of Science searches were carried out using Bangor University subscription (Biological Abstracts, MEDLINE, SciELO Citation Index, Web of Science Core Collections, Zoological Record).Records identified as citations are found only within reference lists of other articles (their existence is not verified by the presence of a publisher version or full text article, unlike hyperlinked citations).