Taxonomy and beyond: ecological trait information in Aphia and WoRMS

Added on 2022-07-01 13:03:20 by Dekeyzer, Stefanie
In recent years, the WoRMS editors and Data Management Team have made collective efforts towards documenting the following species traits information in Aphia and WoRMS: environment (99,5% complete), functional group (76% complete), qualitative (45% complete) and quantitative body size (9% complete) (percentages are for accepted species in Aphia). The availability of these traits greatly enhances the usability and utility of WoRMS towards ecologists and the public at large.
In 2018, the WoRMS Steering Committee identified “documenting relevant species traits” as one of the content priorities for WoRMS. The relevance of traits and their integration with the taxonomy of WoRMS however already dates back to 2015, when Costello et al., 2015 prioritized 10 marine species traits to document: Taxonomy, Environment, Geography, Depth, Body size, Substratum, Mobility, Skeleton, Diet and Reproduction.

Taxonomy, which is not actually a trait, is the main goal of WoRMS, and geography and depth are covered by the distribution module in WoRMS. Environment and body size were considered as the most straightforward traits of this list; meaning this information is easy to find rapidly and can be applied across all taxa in WoRMS. Therefore, it was decided to first focus on collecting information for these two traits in WoRMS.

Since long, environment information has been included in WoRMS as the “environment flag”. This flag indicates whether a species is marine, brackish, freshwater and/or terrestrial. In addition, the “functional group” trait documents whether a species belongs to the benthos, plankton, nekton, etc.

For body size, WoRMS makes the distinction between quantitative and qualitative body size. While quantitative body sizes are numerical values (e.g. 10 mm minimum length for the adult), qualitative body sizes refer to size classes. To document the qualitative body size, four size classes were agreed upon by the WoRMS Steering Committee: Microbiota (< 0.2 mm), Meiobiota (0.2 – 2.0 mm), Macrobiota (2.0 - 200 mm) and Megabiota (> 200 mm). We are aware that other classifications can have different size boundaries, but these size classes were chosen by the WoRMS SC to be applicable to most taxa in WoRMS.

For both functional group and body size, life stage (adult, larva, specific life stages) and gender information (male, female, etc.) can be documented, if available. All trait information is linked to a source, either a publication, database or expert opinion.

Before 2019, both functional group and body size were documented in Aphia and WoRMS to some extent, but not systematically, and not for all species. To complement this trait information, the WoRMS Data Management Team started a “traits data mining exercise” in 2019. Thanks to the positive responses of many editors, environment is now 99,5% complete, functional group 76%, qualitative body size 45%, and quantitative body size 9%. These are the numbers for the accepted species in Aphia. If we look at the accepted, extant, marine species, the numbers are even higher: 100% complete for environment, 81% for functional group, 47% for qualitative body size, and 17% for quantitative body size. More statistics can be found here. Definitions of all traits and values currently available in WoRMS and Aphia can be consulted here.

If you want to help completing these traits even more, please contact

This work is supported by LifeWatch Belgium, part of the E-Science European LifeWatch Infrastructure for Biodiversity and Ecosystem Research. LifeWatch is a distributed virtual laboratory, which is used for different aspects of biodiversity research. The Species Information Backbone of LifeWatch aims at bringing together taxonomic and species-related data and at filling the gaps in our knowledge. In addition, it gives support to taxonomic experts by providing them logistic and financial support for the organization of meetings and workshops related to expanding the content and enhancing the quality of taxonomic databases.

Image credit: Verhelst, Pieterjan, image available at here.

Taxonomy and beyond: ecological trait information in Aphia and WoRMS


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