Bias and dispersal in the animal reintroduction literature

We examined the literature on animal reintroductions to assess the challenges facing individual conservation practitioners who wish to access, synthesize and interpret available evidence to inform their decision making. We undertook an extensive search in eight electronic literature databases, using seven different keyword combinations, and added the content of four bibliographies on reintroductions. We found 3,826 potentially relevant publications totalling at least 29,290 pages of text. Taxonomic bias is apparent in the distribution of general and conservation scientific literature and in reintroduction programmes. We examined whether the literature on reintroductions is biased in a similar way. Comparing the distribution of reintroduction publications to numbers of species, reintroduction programmes and the general conservation literature, there is a marked taxonomic bias favouring vertebrates, especially birds and mammals. The bias in relation to reintroduction programmes is surprising and indicates that managers working with invertebrates and amphibians are less willing and/or less able to publish their results than those working with mammals and birds. The reasons for this are unclear. The growth of the cumulative body of literature can be depicted by a sigmoid curve. Almost 40% of the items were scientific journal articles distributed across 335 journals. The large, ever-growing and dispersed evidence base results in an increased need for reviews, which must be systematic to minimize bias.