This tutorial provides best-practice principles when standardising traits with terms of the Ecological Trait-data Standard (ETS, https://terminologies.gfbio.org/terms/ets/pages/).

We focus this document on the first of the three use-cases for the ETS vocabulary: The publication of project-specific primary data. To comply with the FAIR principles of scientific data management and aim at findability, accessibility, interoperability and reusability (Wilkinson et al. 2016), trait data should apply the following principles when preparing data for publication:

Example 1 - Apply standard terms for matrices

If trait data have been collated at the species level from different literature sources or from expert knowledge, or as aggregated measurements collated from raw data, they usually are reported in a observation-level wide-table format, with a column of values for each trait recorded and a row for each species (or taxon) for which data were available. The wide-table format is widely used for the production of lookup-tables at the species level, which may either report qualitative facts (from literature or expert knowledge) or aggregated quantitative traits (averages or ranges of trait values for this taxon).

This wide-table format is straightforward for maintaining and managing new data for the data author. In terms of analysis, it allows to easily correlate traits with each other and analyse trade-offs between traits. However, wide-tables need to clearly differentiate missing data and traits not applicable to a given taxon (often filled in as ‘NA’ or dummy numbers, e.g., ‘999’). Additional information (e.g., on variation of means or literature source) may be stored in secondary columns or accompanying datasheets. When applying the data standard to wide-table data, the columns for taxa or individuals may be labelled using the terms of the ETS. Taxon concepts should be referenced to globally available concepts using URIs, e.g., by referring to GBIF Taxonomy. Taxa authors and fine-grained higher taxonomy must then be consistent with the linked concept, or may be omitted as redundant and to avoid confusion.

Remarks should be provided in a human-readable form within the table and provided with further detail in the metadata, if necessary.

For wide tables, it is essential that the multiple trait columns are labelled in unambiguous ways and be linked to trait concepts provided in the metadata or a secondary spreadsheet.

Example 1 before standardisation; excerpt of original data from Gossner et al. (2015) 2:150013; data DOI: containing eight traits of arthropods from an European grassland; details provided in data publication .
Order Suborder Family SpeciesID Author Body_Size Dispersal_ability Feeding_guild Remark
Araneae Labidognatha Anyphaenidae Anyphaena accentuata (Walckenaer, 1802) 6.25 1.00 c
Araneae Labidognatha Araneidae Aculepeira ceropegia Walckenaer, 1802 11.00 1.00 c
Araneae Labidognatha Araneidae Agalenatea redii (Scopoli, 1763) 6.93 0.50 c
Araneae Labidognatha Araneidae Araneus diadematus Clerck, 1757 11.88 1.00 c
Araneae Labidognatha Araneidae Araneus marmoreus Clerck, 1757 10.03 0.75 c
Araneae Labidognatha Araneidae Araneus quadratus Clerck, 1757 12.25 1.00 c
Araneae Labidognatha Araneidae Araneus sturmi (Hahn, 1831) 4.63 0.75 c
Araneae Labidognatha Araneidae Araneus triguttatus Fabricius, 1775 5.25 0.50 c
Araneae Labidognatha Araneidae Araniella alpica (L. Koch, 1869) 6.00 0.75 c
Araneae Labidognatha Araneidae Araniella cucurbitina (Clerck, 1757) 5.50 1.00 c
Araneae Labidognatha Araneidae Araniella opisthographa (Kulczynski, 1905) 4.38 0.75 c
Araneae Labidognatha Araneidae Argiope bruennichi (Scopoli, 1772) 11.78 1.00 c
Araneae Labidognatha Araneidae Cercidia prominens (Westring, 1851) 5.38 0.50 c
Araneae Labidognatha Araneidae Cyclosa conica (Pallas, 1772) 5.75 0.75 c
Araneae Labidognatha Araneidae Cyclosa oculata (Walckenaer, 1802) 5.08 0.75 c
Araneae Labidognatha Araneidae Gibbaranea gibbosa (Walckenaer, 1802) 6.75 0.00 c
Araneae Labidognatha Araneidae Gibbaranea omoeda (Thorell, 1870) 9.13 0.50 c
Araneae Labidognatha Araneidae Hypsosinga albovittata (Westring, 1851) 4.15 0.50 c
Araneae Labidognatha Araneidae Hypsosinga sanguinea (C.L. Koch, 1844) 3.75 0.75 c
Araneae Labidognatha Araneidae Larinioides cornutus (Clerck, 1757) 10.35 0.75 c
Araneae Labidognatha Araneidae Mangora acalypha (Walckenaer, 1802) 4.50 1.00 c
Araneae Labidognatha Araneidae Nuctenea umbratica (Clerck, 1757) 11.25 1.00 c
Araneae Labidognatha Araneidae Singa hamata (Clerck, 1757) 5.90 0.75 c
Araneae Labidognatha Clubionidae Clubiona brevipes Blackwall, 1841 5.50 0.50 c
Araneae Labidognatha Clubionidae Clubiona diversa O. P.-Cambridge, 1862 4.00 0.50 c
Araneae Labidognatha Clubionidae Clubiona leucaspis Simon, 1932 4.05 0.50 c
Araneae Labidognatha Clubionidae Clubiona neglecta O. P.-Cambridge, 1862 6.25 0.75 c
Araneae Labidognatha Clubionidae Clubiona reclusa O. P.-Cambridge, 1863 5.75 0.75 c
Araneae Labidognatha Clubionidae Clubiona stagnatilis Kulczynski, 1897 6.25 0.50 c
Araneae Labidognatha Dictynidae Argenna subnigra (O. P.-Cambridge, 1861) 2.25 0.75 c
Araneae Labidognatha Dictynidae Dictyna pusilla Thorell, 1856 2.45 0.50 c
Araneae Labidognatha Dictynidae Lathys humilis (Blackwall, 1855) 2.20 0.50 c
Araneae Labidognatha Dictynidae Nigma flavescens (Walckenaer, 1830) 3.08 0.75 c
Araneae Labidognatha Gnaphosidae Micaria pulicaria (Sundevall, 1831) 3.55 1.00 c
Araneae Labidognatha Linyphiidae Araeoncus humilis (Blackwall, 1841) 1.60 1.00 c
Araneae Labidognatha Linyphiidae Baryphyma pratense (Blackwall, 1861) 2.20 0.50 c
Araneae Labidognatha Linyphiidae Bathyphantes approximatus (O. P.-Cambridge, 1871) 2.63 0.50 c
Araneae Labidognatha Linyphiidae Bathyphantes gracilis (Blackwall, 1841) 1.98 1.00 c
Araneae Labidognatha Linyphiidae Bathyphantes parvulus (Westring, 1851) 2.15 0.75 c
Araneae Labidognatha Linyphiidae Centromerita bicolor (Blackwall, 1833) 3.25 1.00 c
Araneae Labidognatha Linyphiidae Centromerus sylvaticus (Blackwall, 1841) 3.43 1.00 c
Araneae Labidognatha Linyphiidae Ceratinella brevipes (Westring, 1851) 1.45 0.50 c
Araneae Labidognatha Linyphiidae Ceratinella scabrosa (O. P.-Cambridge, 1871) 1.88 0.50 c
Araneae Labidognatha Linyphiidae Cinetata gradata (Simon, 1881) 1.45 0.50 c
Araneae Labidognatha Linyphiidae Cnephalocotes obscurus (Blackwall, 1834) 1.73 0.75 c
Example 1 after standardisation. Column names mapped to ETS terms; taxa are mapped to taxon concepts in published terminologies via URIs. Trait columns are not standardised and respective definitions and units must be provided in the accompanying metadata.
scientificName order family taxonID Body_Size Dispersal_ability Feeding_guild measurementRemarks
Anyphaena accentuata Araneae Anyphaenidae http://www.gbif.org/species/2159474 6.25 1.00 c
Aculepeira ceropegia Araneae Araneidae http://www.gbif.org/species/2160943 11.00 1.00 c
Agalenatea redii Araneae Araneidae http://www.gbif.org/species/2154595 6.93 0.50 c
Araneus diadematus Araneae Araneidae http://www.gbif.org/species/2134131 11.88 1.00 c
Araneus marmoreus Araneae Araneidae http://www.gbif.org/species/2160133 10.03 0.75 c
Araneus quadratus Araneae Araneidae http://www.gbif.org/species/2159970 12.25 1.00 c
Araneus sturmi Araneae Araneidae http://www.gbif.org/species/2159735 4.63 0.75 c non-grassland species
Araneus triguttatus Araneae Araneidae http://www.gbif.org/species/2160067 5.25 0.50 c non-grassland species
Araniella alpica Araneae Araneidae http://www.gbif.org/species/2159883 6.00 0.75 c non-grassland species
Araniella cucurbitina Araneae Araneidae http://www.gbif.org/species/2158387 5.50 1.00 c
Araniella opisthographa Araneae Araneidae http://www.gbif.org/species/2158384 4.38 0.75 c
Argiope bruennichi Araneae Araneidae http://www.gbif.org/species/2158385 11.78 1.00 c
Cercidia prominens Araneae Araneidae http://www.gbif.org/species/2144644 5.38 0.50 c
Cyclosa conica Araneae Araneidae http://www.gbif.org/species/5170994 5.75 0.75 c
Cyclosa oculata Araneae Araneidae http://www.gbif.org/species/2134203 5.08 0.75 c
Gibbaranea gibbosa Araneae Araneidae http://www.gbif.org/species/2134053 6.75 0.00 c
Gibbaranea omoeda Araneae Araneidae http://www.gbif.org/species/2134068 9.13 0.50 c non-grassland species
Hypsosinga albovittata Araneae Araneidae http://www.gbif.org/species/2134110 4.15 0.50 c
Hypsosinga sanguinea Araneae Araneidae http://www.gbif.org/species/2138915 3.75 0.75 c
Larinioides cornutus Araneae Araneidae http://www.gbif.org/species/2138546 10.35 0.75 c
Mangora acalypha Araneae Araneidae http://www.gbif.org/species/2138356 4.50 1.00 c
Nuctenea umbratica Araneae Araneidae http://www.gbif.org/species/2138349 11.25 1.00 c non-grassland species
Singa hamata Araneae Araneidae http://www.gbif.org/species/2158735 5.90 0.75 c
Clubiona brevipes Araneae Clubionidae http://www.gbif.org/species/2137224 5.50 0.50 c non-grassland species
Clubiona diversa Araneae Clubionidae http://www.gbif.org/species/2143869 4.00 0.50 c
Clubiona leucaspis Araneae Clubionidae http://www.gbif.org/species/2144214 4.05 0.50 c non-grassland species
Clubiona neglecta Araneae Clubionidae http://www.gbif.org/species/2143966 6.25 0.75 c
Clubiona reclusa Araneae Clubionidae http://www.gbif.org/species/2144189 5.75 0.75 c
Clubiona stagnatilis Araneae Clubionidae http://www.gbif.org/species/2144246 6.25 0.50 c
Argenna subnigra Araneae Dictynidae http://www.gbif.org/species/2143910 2.25 0.75 c
Dictyna pusilla Araneae Dictynidae http://www.gbif.org/species/2137146 2.45 0.50 c
Lathys humilis Araneae Dictynidae http://www.gbif.org/species/2158202 2.20 0.50 c non-grassland species
Nigma flavescens Araneae Dictynidae http://www.gbif.org/species/2158180 3.08 0.75 c non-grassland species
Micaria pulicaria Araneae Gnaphosidae http://www.gbif.org/species/2144854 3.55 1.00 c
Araeoncus humilis Araneae Linyphiidae http://www.gbif.org/species/2158811 1.60 1.00 c
Baryphyma pratense Araneae Linyphiidae http://www.gbif.org/species/2158809 2.20 0.50 c
Bathyphantes approximatus Araneae Linyphiidae http://www.gbif.org/species/2160397 2.63 0.50 c
Bathyphantes gracilis Araneae Linyphiidae http://www.gbif.org/species/2160408 1.98 1.00 c
Bathyphantes parvulus Araneae Linyphiidae http://www.gbif.org/species/2159204 2.15 0.75 c
Centromerita bicolor Araneae Linyphiidae http://www.gbif.org/species/2144779 3.25 1.00 c
Centromerus sylvaticus Araneae Linyphiidae http://www.gbif.org/species/2159061 3.43 1.00 c
Ceratinella brevipes Araneae Linyphiidae http://www.gbif.org/species/5168243 1.45 0.50 c
Ceratinella scabrosa Araneae Linyphiidae http://www.gbif.org/species/2145001 1.88 0.50 c non-grassland species
Cinetata gradata Araneae Linyphiidae http://www.gbif.org/species/2158999 1.45 0.50 c non-grassland species
Cnephalocotes obscurus Araneae Linyphiidae http://www.gbif.org/species/2159393 1.73 0.75 c

Example 2 - provide structure in long-table

In observation wide-tables, each row is centered around a single physical occurrence of a species, e.g., phenotypic variation of traits within species would usually be recorded per observation where each replicate taken on a distinct individual specimen would be recorded in a row, with the respective trait values stored in columns (see Table B1). Those data are common in investigations of evolutionary trade-offs and trait correlation, or of intra-specific variation along environmental gradients. Occurrence data would also capture phenotypic variation arising from morphotypes and sexual dimorphism. This format is the most intuitive for recording own empirical measurements and therefore is common for measured quantitative data but rarely found for reported qualitative facts obtained from the literature.

A more effective method that allows for high flexibility and easier data merging is the storage of traitdata in long-table formats (Wickham 2014; Parr et al. 2016). This data format corresponds has a row-based structure: each row contains a single measurement or fact of a specific trait, referenced to a single specimen (or one occurrence of an individual organism at a particular space and time) which is assigned to a specific taxon (see Table B2). Identifiers can provide structure and link measurements that are correlated by assigning a unique ID for each single individual. Also, multivariate trait measurements can be recorded in this format by linking multiple rows via a unique measurement identifier. Long-table datasets purport multiple advantages for data handling (e.g., filtering, sub-setting and aggregating data), visualization (e.g., plot measured values by factor variable or taxon) and statistical modelling (e.g., ANOVA for testing difference of trait value by sex) (Wickham 2014). As long-table data share a larger set of columns, merging of datasets is in most cases easier for the end-user.

However, a disadvantage of the long-table data structure is the mixing of units or even factor levels in the ‘traitValue’ column. The mixed content of this column prohibits filtering data based on their values. Data-splitting techniques or a database system are tools to disentangle the data. Note also, how the datasets become bulkier, as many information and labels are now repeated on all measurements as instances of the same individual organism (i.e., one occurrence).

Example 2 before standardisation. Data are stored in observation wide-table format, i.e., one row contains a single specimen with multiple trait measurements (in columns). Units and specific information on measurements must be reported in the metadata of the dataset. Data extract from Mangels et al. (released within the data management system of the Biodiversity Exploratories, BExIS:21247).
label species plot weight wing_length wing_width wing_area wing_loading
F1 Chiasmia_clathrata HEG9 5.174 12.59 8.34 141.9974 0.0364
F2 Xanthorhoe_spadicearia HEG9 8.058 11.38 7.63 99.4278 0.0810
F3 Chiasmia_clathrata HEG4 5.586 15.01 11.40 231.4057 0.0241
F4 Chiasmia_clathrata HEG6 4.797 14.90 12.39 249.6584 0.0192
F6 Chiasmia_clathrata HEG9 14.263 11.47 13.60 210.9555 0.0676
F7 Chiasmia_clathrata HEG9 4.731 12.82 11.61 201.2838 0.0235
F8 Chiasmia_clathrata HEG9 9.200 12.85 13.85 240.6808 0.0382
F11 Chiasmia_clathrata HEG9 4.611 9.83 13.85 184.1161 0.0250
F12 Xanthorhoe_spadicearia HEG9 5.173 10.59 6.63 80.3989 0.0643
F14 Chiasmia_clathrata HEG9 5.181 12.50 11.63 196.5976 0.0264
F15 Chiasmia_clathrata HEG9 14.159 13.50 8.33 152.0783 0.0931
F16 Chiasmia_clathrata HEG9 8.745 12.44 12.06 202.8879 0.0431
Example 2 after standardisation into measurement long-table format. Each row contains a single measurement linked to an observation of an individual specimen, i.e., an occurrence, via identifiers. Only three traits have been selected from the original data, and rows have been cut off to fit the page.
scientificName traitName traitValue traitUnit traitID verbatimTraitName taxonID occurrenceID measurementID locationID
Chiasmia clathrata wing_length 12.5900 mm wing_length http://www.gbif.org/species/4525078 F1 2557 HEG9
Chiasmia clathrata body_weight 5.1740 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/4525078 F1 1 HEG9
Chiasmia clathrata wing_area 141.9974 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/4525078 F1 7669 HEG9
Xanthorhoe spadicearia wing_length 11.3800 mm wing_length http://www.gbif.org/species/1986166 F2 2558 HEG9
Xanthorhoe spadicearia body_weight 8.0580 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/1986166 F2 2 HEG9
Xanthorhoe spadicearia wing_area 99.4278 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/1986166 F2 7670 HEG9
Chiasmia clathrata wing_length 15.0100 mm wing_length http://www.gbif.org/species/4525078 F3 2559 HEG4
Chiasmia clathrata body_weight 5.5860 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/4525078 F3 3 HEG4
Chiasmia clathrata wing_area 231.4057 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/4525078 F3 7671 HEG4
Chiasmia clathrata wing_length 14.9000 mm wing_length http://www.gbif.org/species/4525078 F4 2560 HEG6
Chiasmia clathrata body_weight 4.7970 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/4525078 F4 4 HEG6
Chiasmia clathrata wing_area 249.6584 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/4525078 F4 7672 HEG6
Chiasmia clathrata wing_length 11.4700 mm wing_length http://www.gbif.org/species/4525078 F6 2561 HEG9
Chiasmia clathrata body_weight 14.2630 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/4525078 F6 5 HEG9
Chiasmia clathrata wing_area 210.9555 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/4525078 F6 7673 HEG9
Chiasmia clathrata wing_length 12.8200 mm wing_length http://www.gbif.org/species/4525078 F7 2562 HEG9
Chiasmia clathrata body_weight 4.7310 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/4525078 F7 6 HEG9
Chiasmia clathrata wing_area 201.2838 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/4525078 F7 7674 HEG9
Chiasmia clathrata wing_length 12.8500 mm wing_length http://www.gbif.org/species/4525078 F8 2563 HEG9
Chiasmia clathrata body_weight 9.2000 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/4525078 F8 7 HEG9
Chiasmia clathrata wing_area 240.6808 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/4525078 F8 7675 HEG9
Chiasmia clathrata wing_length 9.8300 mm wing_length http://www.gbif.org/species/4525078 F11 2564 HEG9
Chiasmia clathrata body_weight 4.6110 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/4525078 F11 8 HEG9
Chiasmia clathrata wing_area 184.1161 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/4525078 F11 7676 HEG9
Xanthorhoe spadicearia wing_length 10.5900 mm wing_length http://www.gbif.org/species/1986166 F12 2565 HEG9
Xanthorhoe spadicearia body_weight 5.1730 mg http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Body_weight weight http://www.gbif.org/species/1986166 F12 9 HEG9
Xanthorhoe spadicearia wing_area 80.3989 mm2 http://t-sita.cesab.org/BETSI_vizInfo.jsp?trait=Wing_surface wing_area http://www.gbif.org/species/1986166 F12 7677 HEG9
Chiasmia clathrata wing_length 12.5000 mm wing_length http://www.gbif.org/species/4525078 F14 2566 HEG9

Example 3 - apply ETS extensions in trait-data table

If data contain covariate information, the two-dimensional data table can cover these by adding more columns. The three extensions of the ETS complement the core terms according to different layers of metadata information: 1) the “taxon” extension includes terms to describe more details on the taxon concept applied, 2) the “Measurement or Fact” extension adds information on the methodology or context of the measurement of the trait value, and 3) the “occurrence” extension provides terms to describe the individual specimen and its observation context.

A data table for instance should report on the taxonomic resolution of the trait observation, especially if it is reported on something else than the species level (by setting taxonRank: genus). The additional terms for taxon hierarchies (kingdom to genus) would allow the data user to extract information on genera or families, but this would be redundant with an unambiguous taxon concept has being provided within taxonID. Further columns would provide detail on the measurement accuracy (measurementResolution) or the number of individuals on which an aggregated measure has been determined (by reporting individualCount: n and aggregateMeasure: ‘TRUE’). Data providers can easily contain information on sex or life stage of the specimen (using terms sex or lifeStage), or on the location of sampling (e.g., verbatimLocality, all ‘occurrence’ terms).

If data are provided in a single two-dimensional data table that applies standard terms of the ETS, this may increase readability and facilitate re-use by synthesis researchers as they do not need to process information stored elsewhere. Data tables conforming to the same data standard can be merged with ease.

Example 3 before standardisation; Excerpt of data from Gossner et al. (2015b) Ecology, 96, 1154–1154. doi: on measurements of traits in Heteroptera.
ID Order Suborder Family SpeciesID Author Sex Source Center_Sampling_region Body_length Body_width Body_height Thorax_length
8 Hemiptera Heteroptera Tingidae Acalypta parvula (Fallen, 1807) m Biodiversity Exploratories 48 43’ N 09 37’ E 1.65 0.49 0.51 0.68
9 Hemiptera Heteroptera Tingidae Acalypta platycheila (Fieber, 1844) f Zoological State Collection Munich 48 11’ N 10 45’ E 2.39 1.13 0.73 0.59
10 Hemiptera Heteroptera Tingidae Acalypta platycheila (Fieber, 1844) f Zoological State Collection Munich 48 48’ N 11 06’ E 2.42 1.30 0.77 0.60
11 Hemiptera Heteroptera Tingidae Acalypta platycheila (Fieber, 1844) m Zoological State Collection Munich 49 29’ N 10 59’ E 2.44 1.19 0.71 0.63
12 Hemiptera Heteroptera Tingidae Acalypta platycheila (Fieber, 1844) m Biodiversity Exploratories 51 20’ N 10 41’ E 1.63 0.81 0.56 0.50
13 Hemiptera Heteroptera Miridae Acetropis carinata (Herrich-Schäffer, 1841) f Biodiversity Exploratories 51 20’ N 10 41’ E 6.45 1.79 1.05 0.74
14 Hemiptera Heteroptera Miridae Acetropis carinata (Herrich-Schäffer, 1841) f Zoological State Collection Munich NA 6.28 1.82 1.23 0.72
15 Hemiptera Heteroptera Miridae Acetropis carinata (Herrich-Schäffer, 1841) m Biodiversity Exploratories 53 02’ N 13 83’ E 4.46 0.98 1.49 0.57
Example 3 after standardisation; application of terms of the ETS extensions structure the two-dimensional data table. Excerpt of data from Gossner et al. (2015b) Ecology, 96, 1154–1154. doi: .
scientificName traitName traitValue traitUnit occurrenceID taxonID family sex basisOfRecord basisOfRecordDescription decimalLatitude decimalLongitute
Acalypta parvula Body_height 0.51 mm 8 http://www.gbif.org/species/2020740 Tingidae m PreservedSpecimen Biodiversity Exploratories 48.71667 9.61667
Acalypta parvula Body_width 0.49 mm 8 http://www.gbif.org/species/2020740 Tingidae m PreservedSpecimen Biodiversity Exploratories 48.71667 9.61667
Acalypta parvula Body_length 1.65 mm 8 http://www.gbif.org/species/2020740 Tingidae m PreservedSpecimen Biodiversity Exploratories 48.71667 9.61667
Acalypta platycheila Body_height 0.73 mm 9 http://www.gbif.org/species/4489001 Tingidae f PreservedSpecimen Zoological State Collection Munich 48.18333 10.75000
Acalypta platycheila Body_length 2.39 mm 9 http://www.gbif.org/species/4489001 Tingidae f PreservedSpecimen Zoological State Collection Munich 48.18333 10.75000
Acalypta platycheila Body_width 1.13 mm 9 http://www.gbif.org/species/4489001 Tingidae f PreservedSpecimen Zoological State Collection Munich 48.18333 10.75000
Acalypta platycheila Thorax_width 1.13 mm 9 http://www.gbif.org/species/4489001 Tingidae f PreservedSpecimen Zoological State Collection Munich 48.18333 10.75000
Acalypta platycheila Body_height 0.77 mm 10 http://www.gbif.org/species/4489001 Tingidae f PreservedSpecimen Zoological State Collection Munich 48.80000 11.10000
Acalypta platycheila Thorax_width 1.17 mm 10 http://www.gbif.org/species/4489001 Tingidae f PreservedSpecimen Zoological State Collection Munich 48.80000 11.10000
Acalypta platycheila Body_length 2.42 mm 10 http://www.gbif.org/species/4489001 Tingidae f PreservedSpecimen Zoological State Collection Munich 48.80000 11.10000
Acalypta platycheila Body_width 1.30 mm 10 http://www.gbif.org/species/4489001 Tingidae f PreservedSpecimen Zoological State Collection Munich 48.80000 11.10000
Acalypta platycheila Thorax_width 1.09 mm 11 http://www.gbif.org/species/4489001 Tingidae m PreservedSpecimen Zoological State Collection Munich 49.48333 10.98333
Acalypta platycheila Body_height 0.71 mm 11 http://www.gbif.org/species/4489001 Tingidae m PreservedSpecimen Zoological State Collection Munich 49.48333 10.98333
Acalypta platycheila Body_length 2.44 mm 11 http://www.gbif.org/species/4489001 Tingidae m PreservedSpecimen Zoological State Collection Munich 49.48333 10.98333
Acalypta platycheila Body_width 1.19 mm 11 http://www.gbif.org/species/4489001 Tingidae m PreservedSpecimen Zoological State Collection Munich 49.48333 10.98333
Acalypta platycheila Thorax_width 0.60 mm 12 http://www.gbif.org/species/4489001 Tingidae m PreservedSpecimen Biodiversity Exploratories 51.33333 10.68333
Acalypta platycheila Body_height 0.56 mm 12 http://www.gbif.org/species/4489001 Tingidae m PreservedSpecimen Biodiversity Exploratories 51.33333 10.68333
Acalypta platycheila Body_length 1.63 mm 12 http://www.gbif.org/species/4489001 Tingidae m PreservedSpecimen Biodiversity Exploratories 51.33333 10.68333
Acalypta platycheila Body_width 0.81 mm 12 http://www.gbif.org/species/4489001 Tingidae m PreservedSpecimen Biodiversity Exploratories 51.33333 10.68333
Acetropis carinata Body_height 1.05 mm 13 http://www.gbif.org/species/8426653 Miridae f PreservedSpecimen Biodiversity Exploratories 51.33333 10.68333
Acetropis carinata Body_length 6.45 mm 13 http://www.gbif.org/species/8426653 Miridae f PreservedSpecimen Biodiversity Exploratories 51.33333 10.68333
Acetropis carinata Body_width 1.79 mm 13 http://www.gbif.org/species/8426653 Miridae f PreservedSpecimen Biodiversity Exploratories 51.33333 10.68333
Acetropis carinata Thorax_width 1.45 mm 13 http://www.gbif.org/species/8426653 Miridae f PreservedSpecimen Biodiversity Exploratories 51.33333 10.68333
Acetropis carinata Body_height 1.23 mm 14 http://www.gbif.org/species/8426653 Miridae f PreservedSpecimen Zoological State Collection Munich NA NA
Acetropis carinata Body_length 6.28 mm 14 http://www.gbif.org/species/8426653 Miridae f PreservedSpecimen Zoological State Collection Munich NA NA
Acetropis carinata Thorax_width 1.52 mm 14 http://www.gbif.org/species/8426653 Miridae f PreservedSpecimen Zoological State Collection Munich NA NA
Acetropis carinata Body_width 1.82 mm 14 http://www.gbif.org/species/8426653 Miridae f PreservedSpecimen Zoological State Collection Munich NA NA
Acetropis carinata Body_height 1.49 mm 15 http://www.gbif.org/species/8426653 Miridae m PreservedSpecimen Biodiversity Exploratories 53.03333 14.38333
Acetropis carinata Body_length 4.46 mm 15 http://www.gbif.org/species/8426653 Miridae m PreservedSpecimen Biodiversity Exploratories 53.03333 14.38333

Example 4 - apply ETS extensions in relational databse

Two-dimensional spreadsheets are however limited in the number and complexity of co-variates they can contain. As such, for datasets containing multi-layered information on observations, traits, taxa and environmental context, the use of relational database structures may be indicated. Relational databases help to avoid content duplication, as the core table will only maintain identifiers, that relate to secondary data tables containing multiple specifications on the identifier level. For instance, the core table may specify ‘occurrenceID’ for which specific information can be found in a lookup table. The ETS may be applied to describe columns within the individual data tables of relational databases. Compatibility with other database structures is warranted, as ETS terms map to terms of the Darwin Core Standard used in other suggested database structures for trait data, like the generic structure for plant trait databases (Kattge et al. 2011) or the TraitBank structure (Parr et al. 2016).

For publishing relational databases, it is however important to provide sufficient information on how the individual data tables are related, e.g., in a machine readable metadata specification (e.g., in EML language). Further, it must be ensured that data tables are always contained in a single data publication and are not distributed independently of each other, as this would cause issues of broken links if data are updated or lost. Both requirements are met if data are released as a packaged archive, for instance following the Darwin Core Archive specification (Robertson et al. 2009).

Example 4: original data of Example 3 after standardisation into relational database structure, providing taxon and occurrence level information in secondary data tables (Fig. 8 and 9, respectively).
scientificName traitName traitValue traitUnit taxonID occurrenceID
Acalypta parvula Body_height 0.51 mm http://www.gbif.org/species/2020740 8
Acalypta parvula Body_width 0.49 mm http://www.gbif.org/species/2020740 8
Acalypta parvula Body_length 1.65 mm http://www.gbif.org/species/2020740 8
Acalypta platycheila Body_height 0.73 mm http://www.gbif.org/species/4489001 9
Acalypta platycheila Body_length 2.39 mm http://www.gbif.org/species/4489001 9
Acalypta platycheila Body_width 1.13 mm http://www.gbif.org/species/4489001 9
Acalypta platycheila Thorax_width 1.13 mm http://www.gbif.org/species/4489001 9
Acalypta platycheila Body_height 0.77 mm http://www.gbif.org/species/4489001 10
Acalypta platycheila Thorax_width 1.17 mm http://www.gbif.org/species/4489001 10
Acalypta platycheila Body_length 2.42 mm http://www.gbif.org/species/4489001 10
Acalypta platycheila Body_width 1.30 mm http://www.gbif.org/species/4489001 10
Acalypta platycheila Thorax_width 1.09 mm http://www.gbif.org/species/4489001 11
Acalypta platycheila Body_height 0.71 mm http://www.gbif.org/species/4489001 11
Acalypta platycheila Body_length 2.44 mm http://www.gbif.org/species/4489001 11
Acalypta platycheila Body_width 1.19 mm http://www.gbif.org/species/4489001 11
Acalypta platycheila Thorax_width 0.60 mm http://www.gbif.org/species/4489001 12
Acalypta platycheila Body_height 0.56 mm http://www.gbif.org/species/4489001 12
Acalypta platycheila Body_length 1.63 mm http://www.gbif.org/species/4489001 12
Acalypta platycheila Body_width 0.81 mm http://www.gbif.org/species/4489001 12
Acetropis carinata Body_height 1.05 mm http://www.gbif.org/species/8426653 13
Acetropis carinata Body_length 6.45 mm http://www.gbif.org/species/8426653 13
Acetropis carinata Body_width 1.79 mm http://www.gbif.org/species/8426653 13
Acetropis carinata Thorax_width 1.45 mm http://www.gbif.org/species/8426653 13
Acetropis carinata Body_height 1.23 mm http://www.gbif.org/species/8426653 14
Acetropis carinata Body_length 6.28 mm http://www.gbif.org/species/8426653 14
Acetropis carinata Thorax_width 1.52 mm http://www.gbif.org/species/8426653 14
Acetropis carinata Body_width 1.82 mm http://www.gbif.org/species/8426653 14
Acetropis carinata Body_height 1.49 mm http://www.gbif.org/species/8426653 15
Acetropis carinata Body_length 4.46 mm http://www.gbif.org/species/8426653 15
Acetropis carinata Body_width 0.98 mm http://www.gbif.org/species/8426653 15
Acetropis carinata Thorax_width 1.45 mm http://www.gbif.org/species/8426653 15
Example 4, data table on taxon level information after standardisation. Data extracted from GBIF backbone taxonomy.
taxonID scientificName scientificNameAuthorship taxonRank kingdom phylum class order family genus taxonomy
http://www.gbif.org/species/2020740 Acalypta parvula (Fallén, 1807) species Animalia Arthropoda Insecta Hemiptera Tingidae Acalypta GBIF Backbone Taxonomy
http://www.gbif.org/species/4489001 Acalypta platycheila (Fieber, 1844) species Animalia Arthropoda Insecta Hemiptera Tingidae Acalypta GBIF Backbone Taxonomy
http://www.gbif.org/species/8426653 Acetropis carinata (Herrich-Schaeffer, 1841) species Animalia Arthropoda Insecta Hemiptera Miridae Acetropis GBIF Backbone Taxonomy
Example 4, data table on occurrence level information after standardisation, accompanying Table 7.
occurrenceID sex basisOfRecord basisOfRecordDescription references decimalLatitude decimalLongitute
8 m PreservedSpecimen Biodiversity Exploratories AEG_26_KEF_august2008 48.71667 9.61667
9 f PreservedSpecimen Zoological State Collection Munich Schwabmünchen_Schwaben_27.5.1965_leg.G.Schuster 48.18333 10.75000
10 f PreservedSpecimen Zoological State Collection Munich Altmühltal_Wellheim_18.7.34_K.Schmidt 48.80000 11.10000
11 m PreservedSpecimen Zoological State Collection Munich Fürth.i.B._Vach_25.5.32_K.Schmidt 49.48333 10.98333
12 m PreservedSpecimen Biodiversity Exploratories HEG_42_NO_BF_juni2008 51.33333 10.68333
13 f PreservedSpecimen Biodiversity Exploratories HEG_46_KEF_juni2008 51.33333 10.68333
14 f PreservedSpecimen Zoological State Collection Munich Ungarn_Sammlung.Hüter NA NA
15 m PreservedSpecimen Biodiversity Exploratories SEG_13_KEF_juni2008 53.03333 14.38333

References

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Gossner, M. M., N. K. Simons, L. Höck, and W. W. Weisser. 2015b. Morphometric measures of Heteroptera sampled in grasslands across three regions of Germany. Ecology 96:1154–1154.

Kattge, J., K. Ogle, G. Bönisch, S. Díaz, S. Lavorel, J. Madin, K. Nadrowski, et al. 2011. A generic structure for plant trait databases. Methods in Ecology and Evolution 2:202–213.

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