Taxonomic heterogeneity in sampling, occurrence data origin and quality for 24 taxonomic classes. Top: Proportion of species per class recorded in GBIF with at least one occurrence (light green: p>1), with more than 20 occurrences (green: p>20), and with more than 20 spatially distinct occurrences (i.e. “decently” sampled – dark green: p>20d). For all classes, except Aves, less than 1/3 of all species are “decently” sampled. Classes are ranked according to their proportion of “decently” sampled species. Middle
: Occurrence origin (basisOfRecord) for each class. Some classes like Amphibia have a high proportion of occurrences based on specimens (blue: living or preserved specimen, material samples or fossils), whereas others like Aves have a majority of occurrences based on observation (orange: machine or human observation, literature). Grey bars show occurrences where the record basis is unknown. Classes are ranked according to their proportion of specimen-based occurrences. Bottom
: Data incompleteness. Proportion of occurrences with spatial (purple) or temporal (yellow) inaccuracies for each class. Spatial inaccuracy corresponds to an occurrence lacking coordinates or tagged has having geospatial issues by GBIF. Temporal inaccuracy corresponds to a sampling event with no specified month or year. Classes are ranked according to their proportion of occurrences with spatial issues.