TDWGAudiovisual Core (commonly known as Audubon Core or AC) is a TDWG standard providing a comprehensive set of vocabularies for describing biodiversity-related multimedia resources and collections. It serves as the primary metadata framework for images, audio recordings, video, and other media documenting the natural world, enabling researchers and institutions to manage, discover, and share biodiversity media effectively.
Background
The Audiovisual Core standard was developed by the GBIF/TDWG Multimedia Resources Task Group and ratified by Biodiversity Information Standards (TDWG) on October 28, 2013. The standard emerged from the need for a structured way to describe the rapidly growing volume of biodiversity multimedia — from specimen photographs and field recordings to microscopy images and ecological video surveys.
The standard has been actively maintained since ratification. A dedicated Audiovisual Core Maintenance Group, whose charter was approved in January 2018, manages vocabulary term additions and changes and maintains supporting documentation. The most recent substantive update across the standard's documents occurred on February 24, 2023.
Purpose & Scope
Audubon Core addresses the metadata needs of biodiversity multimedia at both the individual resource and collection levels. The vocabularies aim to represent information that helps determine whether a particular resource or collection is fit for a specific biodiversity science application before acquiring the media. Key concerns include:
- Management of media and collections
- Descriptions of content
- Taxonomic, geographic, and temporal coverage
- Appropriate methods for retrieval, attribution, and reproduction
Structure
The standard comprises six vocabularies and nine documents:
| Vocabulary | Namespace URI |
|---|---|
| AC main vocabulary | http://rs.tdwg.org/ac/ |
| variant controlled vocabulary | http://rs.tdwg.org/acvariant/ |
| format controlled vocabulary | http://rs.tdwg.org/format/ |
| subtype controlled vocabulary | http://rs.tdwg.org/acsubtype/ |
| subjectOrientation controlled vocabulary | http://rs.tdwg.org/acorient/ |
| subjectPart controlled vocabulary | http://rs.tdwg.org/acpart/ |
Key documents include the Term List (normative), the Structure document, the Introduction, and the Guide, along with controlled vocabulary term lists for format, subjectOrientation, subjectPart, subtype, and variant.
Serializations & Technical Formats
Audubon Core terms use RDF-based identifiers following TDWG conventions. The vocabularies borrow terms from Dublin Core (dc:format, dcterms:format) and define controlled vocabularies for specific property values. Terms are identified by permanent IRIs under the rs.tdwg.org domain.
Governance & Maintenance
The standard is maintained by the Audiovisual Core Maintenance Group under TDWG's Vocabulary Maintenance Specification. The group manages term additions and changes, maintains documentation, and may establish Task Groups for broader changes. Community participation is welcomed through the group's GitHub Issues tracker, which serves as the mechanism for suggesting changes and raising discussion items.
Notable contributors include Robert A. Morris (University of Massachusetts Boston), Gregor Hagedorn (JKI, Germany), Steve Baskauf (Vanderbilt University), and numerous other collaborators from institutions worldwide.
Notable Implementations
Audubon Core is used by biodiversity data aggregators and natural history collections for describing multimedia associated with specimen records and biodiversity observations. It complements Darwin Core, which handles occurrence and taxonomic data, by providing the metadata framework for associated media resources.
Related Standards
- Darwin Core — Complementary TDWG standard for biodiversity occurrence data
- Dublin Core — Audubon Core borrows several Dublin Core terms