Chloé Schmidt, Sean Hoban, Margaret Hunter, Ivan Paz-Vinas, Colin Garroway

The International Union for Conservation of Nature (IUCN) Red List is an important and widely used conservation prioritization tool. It uses information about species range size, habitat quality and fragmentation levels, and trends in abundance to assess species extinction risk. Genetic erosion is an additional key factor determining extinction risk, but the Red List was not designed to assess genetic diversity. Declining populations experience stronger effects of genetic drift and higher rates of inbreeding, which can reduce the efficiency of selection, lead to fitness declines, and hinder species’ capacities to adapt to environmental change. Given the importance of conserving genetic diversity, several studies have attempted to find relationships between Red List status and genetic diversity. Yet, there is still no general consensus on whether genetic diversity is captured by the current Red List categories in a way that is informative for conservation, likely partly due to assessments using different molecular markers and taxa. Here, we synthesize previous work and re-analyze three datasets using different marker types (mitochondrial DNA, microsatellites, and whole genomes) to assess whether genetic diversity accurately predicts Red List threat status. Consistent with previous work we found that on average, species with higher threat status tended to have lower genetic diversity for all marker types, but the strength of these relationships varied across taxa. However, genetic diversity did not predict threat status well for any taxon or marker type. Our analyses indicate that Red List status is not a useful metric for informing species-specific decisions about the protection of genetic diversity. This is unsurprising because the Red List was not designed for conservation at the genetic level. Our findings clearly indicate a need to develop and incorporate metrics specifically developed to assess genetic diversity into our conservation policy frameworks.