Priorities for conservation rely heavily on discovery and assessments

The Red List is one of the most important and widely used sources of biodiversity information, providing conservation assessments for nearly 160,000 species. Here, we assess how the change in available Red List data can influence the selection of spatial conservation priorities and which regions are identified as most critical for conservation. We mapped biodiversity importance based on species ranges and threat status at ∼25 km, ∼50 km, and ∼ 100 km resolutions for two time points: 2010 and 2023. We then analyzed shifts in the top 10 % and 25 % most important areas for biodiversity at global and national levels between the two time points. We find that, globally, conservation priorities shifted over time from higher-income to lower-income countries. Nationally, priority areas in 2010 and 2023 were on average 60 % retained and over 40 % of countries experienced a shift in over half of their priority areas between the two years. Beyond showing large shifts within countries of which areas would be the most important to preserve, our analysis highlights an increasing focus on biodiversity research in developing nations. These shifts showcase the uneven global sampling of biodiversity, which skews our understanding of where to invest to efficiently conserve nature. We recommend increased funding for geographically representative field data collection, and the inclusion of explicit guidelines for regular updates in biodiversity frameworks to ensure conservation strategies remain effective. • IUCN-based important areas for biodiversity can shift considerably over a decade. • Important areas for biodiversity shifted from high-income to low-income regions. • 33–42 % of countries shifted over half of their top 10 % priority areas.