Biodiversity data is the main pillar of conservation planning. The quality of species assessments, however, relies on the availability and standard of occurrence data. If data is scarce—the Wallacean Shortfall—results may be unreliable.
Large, colourful and with plenty of aesthetic appeal, butterflies are a remarkable exception to undersampling of insects. In this study, researchers used GBIF-mediated occurrences of six butterfly families containing more than 8,000 species to identify gaps in inventory data at the global level.
The authors found a positive trend in record accumulation in the past century—particularly since 1990—in most of the world with the exception of Central Africa. The highest levels of inventory completeness are found in Europe, North America, coastal Australia and Southern Africa.
While using regression models to identify predictors of inventory completeness, the authors found road density (i.e. accessibility) to be important, however, this was only at the finest resolution. At a large scale, completeness was better predicted by elevation and density of protected areas.