When population mortality outweighs fertility rates, the long-term survival of the population is not sustainable, resulting in species extinction. Given the current extinction crisis there is an urgent need to maximize the effectiveness of conservation management programs. For many such strategies, well-informed demographic models provide rigorous predictions of population fate, which can be critical for successful conservation. However, the accuracy of these models hinges on the availability of demographic data. Despite the importance of demographic data to inform management of threatened species, there has been no global assessment of demographic information available. We standardized the taxonomy and terms describing traits across 24 databases on demography and/or with demographic life history traits. We developed a Demographic Index of Species Knowledge (DISKo) that shows data availability for fertility and survival, which are the essential data to understand population dynamics, and therefore demographics. Our results show that demographic data for both fertility and mortality is shockingly scarce. This is the case for even the best-studied tetrapod groups. The data with the highest quality (i.e. to be able to forecast population fate) is available for only 3.4% of mammals and just 1% of bird species. For amphibians and reptiles this figure is less than 1% (0.2% for amphibians and 0.3% for reptiles). Knowledge is also geographically biased with glaring data gaps in the tropics. The low number of species with demographic data is surprising because major efforts to tackle comparative questions in ecology and evolution have resulted in the development of numerous species-specific trait databases (e.g. PanTHERIA, Amniote life-history database, AnAge). Our results illustrate the distribution of demographic information across trait-type, phylogeny and space and provide a useful tool for optimizing future research priorities. In addition, they highlight the importance of standardizing terminology and units across parallel database efforts. The next step is to link DISKo with a Genetic Knowledge index that we are developing.
