In the Arctic Trait Database information is not only provided in text format, but also in form of “fuzzy codes”. Our intention by providing this download option is to facilitate trait-based approaches to a variety of users. The coded traits per species matrix (or Q table) can be downloaded and directly imported into R (R Core Team 2013) or other appropriate software.

The fuzzy coding procedure indicates to which extent a taxon exhibits each trait category (Chevenet et al. 1994). It has the advantage that it enables us to analyze diverse kinds of biological information derived from a variety of sources (as those included in the Arctic Traits Database), and that also intermediate scenarios (i.e. when a taxon does not clearly fall into one category or the other) can be accounted for (Chevenet et al. 1994). Although several coding schemes are found in literature, we use the 0–3 coding scheme as it is the most widely used (which facilitates comparisons and exchange of trait information), and provides a compromise between binary codes and many not clearly delineated graduations (Degen et al. 2018, Degen & Faulwetter in prep).

Explanation of fuzzy codes

3 Taxon has total and exclusive affinity for a certain trait category.
2 Taxon has a high affinity for a certain trait category, but other categories can occur with equal (2) or lower (1) affinity.
1 Taxon has a low affinity for a certain trait category.
0 Taxon has no affinity for a certain trait category.

Two coding examples for the trait “Feeding habit” which has six trait categories (FH1 – FH6): Species 1 is a surface deposit feeder, but can switch facultative to suspension feeding, while species 2 is an exclusive suspension feeder.

Feeding habit (FH) Species 1 Species 2
Surface deposit feeder FH1 2 0
Subsurface deposit feeder FH2 0 0
Filter/suspension feeder FH3 1 3
Opportunist/scavenger FH4 0 0
Predator FH5 0 0
Parasite/commensal FH6 0 0

This is how the above example would appear in the matrix downloaded from the Arctic Traits Database. In the download matrix format species are rows, trait categories are columns and the fuzzy codes are the values. Due to the database structure zero codes (“0”) are only displayed when they are backed up by a specific reference (e.g., for the trait category LH3/tube dwelling: “No species within the family Polynoidae is tubiculous”).

FH1 FH2 FH3 FH4 FH5 FH6
Species 1 2 1
Species 2 3

For further reading on trait-based approaches in marine community ecology we recommend Beauchard et al. (2017) and Degen et al. (2018), the latter placing emphasis on the polar regions.

References