The four classes of datasets supported by GBIF start simply and become progressively richer, more structured and more complex.
We encourage data holders to publish the richest data possible to ensure their use across a wider range of research approaches and questions, but not every dataset includes information at the same level of detail. Sharing what is available through GBIF.org is valuable, because even partial information answers some important questions.
At its simplest level, GBIF.org allows institutions to create datasets describing undigitized resources like those in natural history and other collections. All three other dataset classes include this basic information, but this ‘metadata-only’ class offers researchers a valuable tool for discovering and learning about evidence not yet available online. They can also help assess the relative importance and value of undigitized collections and set priorities for future digitization. As with all datasets, GBIF ensures that each metadata dataset is associated with a unique Digital Object Identifier (DOI) to streamline data users’ citation of these resources.
Datasets can also provide a catalogue or list of named organisms, or taxa. While they may include additional details like local species names or specimen citations, these ‘checklists’ typically categorize information along taxonomic, geographic, and thematic lines, or some combination of the three. For example, a dataset that catalogues the Red Listed molluscs of Seychelles has distinct elements of taxonomy (the phylum Mollusca), geography (the island nation of Seychelles) and theme (species deemed imperiled by IUCN experts). Checklists function as a rapid summary or baseline inventory of taxa in a given context.
Other datasets published through GBIF.org have sufficiently consistent detail to contribute information about the location of individual organisms in time and space—that is, they offer evidence of the occurrence of a species (or other taxon) at a particular place on a specified date. Occurrence datasets make up the core of data published through GBIF.org, and examples can range from specimens and fossils in natural history collections, observations by field researchers and citizen scientists, and data gathered from camera traps or remote-sensing satellites.
Occurrence records in these datasets sometimes provide only general locality information, sometimes simply identifying the country, but in many cases more precise locations and geographic coordinates support fine-scale analysis and mapping of species distributions.
Datasets sometimes provide greater detail, not only offering evidence that a species occurred at a given location and date, but also making it possible to assess community composition for broader taxonomic groups or even the abundance of species at multiple times and places. These quantitative or sampling-event datasets typically derive from standard protocols for measuring and monitoring biodiversity like vegetation transects, bird censuses and freshwater or marine sampling.
By indicating the methods, events and relative abundance of species recorded in a sample, these datasets improve comparisons with data collected using the same protocols at different times and places—in some cases, even leading researchers to infer the absence of particular species from particular sites.