Insular bats and research effort: a review of global patterns and priorities

Evidence-based knowledge is critical for the delineation and success of conservation interventions. However, despite limited research resources, research efforts frequently fail to target conservation priorities. Island endemic bats (IEBs) are a poorly studied group inhabiting some of the world's most vulnerable habitats, and for which no review of research allocation has ever been conducted. We conducted a bibliometric review to evaluate the global research patterns for IEBs with respect to individual species, geographical distribution and the International Union for Conservation of Nature (IUCN) Red List categories. Additionally, we studied the relationship between the number of publications and changes in Red List category, and identified species-based and area-based priorities for future research. IEBs are significantly more threatened than bat species that are not island endemics. However, research focusing on IEBs is scarce, centred on species of lesser conservation concern, and spatially asymmetric, overlooking areas of high IEB biodiversity. Conservation-oriented research seems to target species facing high extinction risk, but is extremely thinly and unevenly distributed. Although we found a positive association between research effort and improvement in Red List category, an increase in extinction risk did not trigger more scientific attention. A prioritisation analysis highlighted, as the top five islands for species richness in the least-studied and highest conservation concern IEBs: Sulawesi, Timor, New Guinea, Java, and Borneo. The ten species of highest research priority include threatened and Data Deficient species from Southeast Asian and Pacific islands. Conservation-oriented research seems to be too scarce to satisfy conservation needs. The observed mismatch between research allocation and conservation priorities may reflect the fact that highly endangered species are unattractive targets for fund-raising, due to species crypticity, high research budget requirements, and high risk of project failure. However, our findings support the importance of research for the conservation of IEBs, and we therefore advocate that more attention is directed towards the least-known species