The state of species at global level has generally been declining over the last decades. The IUCN Red List Index of Species Survival (currently available only for amphibians, birds, corals and mammals) shows a contrasting picture: while birds and mammals appear to be relatively stable, the survival chances of amphibian and coral species are in decline. The number of threatened species has doubled between 2000 and 2014. However, in the same period, the number of species assessed increased more than fourfold. This indicates that the knowledge gap related to the conservation status of species is narrowing, even though the status of only 4% of the known non-marine and 3% of the known marine species has been assessed.