The biodiversity we ignore: A global meta-analysis on taxonomic bias

As biodiversity decline continues, there is a critical need to document, monitor, and protect species equitably across the tree of life. However, both scientific research and societal perceptions of biodiversity are often biased toward large, colorful, charismatic, familiar, or otherwise "useful" species. We conducted a global meta-analysis encompassing 905 effect sizes from 78 studies across three decades of research assessing drivers of taxonomic bias. Positive biases were widespread across study designs, regions, and taxonomic scopes, with plants and invertebrates typically receiving disproportionately less attention than vertebrates. However, the magnitude of bias was generally small (Pearson's r < 0.5), suggesting mild impacts on research agendas. Concerningly, conservation priority emerged as the only dimension not consistently associated with positive bias, suggesting a misalignment between research attention, funding, public interest, and conservation needs. We conclude that while biases are pervasive across taxonomic groups, they are subtle-but their conservation consequences warrant urgent correction.