The Catalogue of Life Data Package (CoLDP) and the Taxon Concept Standard (TCS): A comparison

The Catalogue of Life Data Package (CoLDP; Catalogue of Life 2022) is the preferred mechanism for getting data in and out of the ChecklistBank. A CoLDP is a ZIP file containing files with delimiter-separated values, similar to the Darwin Core Archive (DwC-A; Global Biodiversity Information Facility 2023), but does not enforce the DwC-A star schema requiring a single Core file and zero or more Extension files. This makes it preferable for exchanging taxonomic data in tabular format as taxonomic data contains at least three different types of objects—taxa, names and references—that are all interlinked.

TCS (currently still Taxon Concept Schema) is the TDWG (Biodiversity Information Standards) standard for dealing with taxonomic data specifically. An effort is currently underway (TCS 2 Task Group 2023) to free TCS from its XML schema and turn it into a TDWG vocabulary standard that is maintainable under the TDWG Vocabulary Maintenance Specification (VMS; Vocabulary Maintenance Specification Task Group 2017). For a domain standard like TCS, it is essential that it supports an important warehouse of taxonomic information like ChecklistBank and an exchange format like CoLDP. Therefore, as part of the Implementation Experience Report that has to accompany a major update to an existing TDWG standard, a comparison has been undertaken between TCS and the data model behind CoLDP.

While some of the terms CoLDP uses are different from the ones used by TCS, the two specifications are completely compatible. This presentation will highlight some of the key similarities and differences. It is heartening to see that different groups of people independently chose to make the same departure from the existing specification. As TCS will be maintainable—and, in fact, still has to undergo public review—and CoLDP presumably can evolve as well, there are opportunities for TCS and CoLDP to come even closer together than they already are.