Ukrainian Plant Trait Database: UkrTrait v. 1.0

Abstract Background Considering the growing demand for plant trait data and taking into account the lack of trait data from Eastern Europe, especially from its steppic region, we launched a new Ukrainian Plant Trait Database (UkrTrait v. 1.0) aiming at collecting all the available plant trait data from Ukraine. To facilitate further use of this database, we linked the trait terminology to the TRY Plant Trait Database, Thesaurus of Plant Characteristics (TOP) and Plant Trait Ontology (TO). For taxa names, we provide the crosswalks between the Ukrainian checklist and international sources, i.e. GBIF Backbone Taxonomy, World Checklist of Vascular Plants (World Checklist of Vascular Plants (World Checklist of Vascular Plants (WCVP), World Flora Online (WFO) and Euro+Med PlantBase. We aim to integrate our data into the relevant global (TRY Plant Trait Database) and pan-European (FloraVeg.EU) databases. The current version of the database is freely available at the Zenodo repository and will be updated in the future. New information Until now, plant traits for the Ukrainian flora were scattered across literature, often focusing on single species and written mainly in Ukrainian. Additionally, many traits were in grey literature or remained non-digitised, which rendered them inaccessible to the global scientific community. Addressing this gap, our Ukrainian Plant Trait Database (UkrTrait v. 1.0) represents a significant step forward. We compiled and digitised plant traits from local Ukrainian literature sources. Furthermore, we performed our own field and laboratory measurements of various plant traits that were not previously available in literature. In the current version of the UkrTrait, we focus on vascular plant species that are absent from the other European trait databases, with emphasis on species that are representative for the steppe vegetation. Traits assembled from literature include life span (annuals, biennials, perennials), plant height, flowering period (flowering months), life form (by Raunkiaer), plant growth form and others. Our own measured traits include seed mass, seed shape, leaf area, leaf nitrogen concentration and leaf phosphorus concentration. The current version, i.e. UkrTrait v. 1.0, comprises digitised literature data of 287,948 records of 75 traits for 6,198 taxa and our own trait measurements of 2,390 records of 12 traits for 388 taxa.

To facilitate further use of this database, we linked the trait terminology to the TRY Plant Trait Database, Thesaurus of Plant Characteristics (TOP) and Plant Trait Ontology (TO).For taxa names, we provide the crosswalks between the Ukrainian checklist and international sources, i.e.GBIF Backbone Taxonomy, World Checklist of Vascular Plants

Introduction
Plant traits, measured at the species level, reflect plants' performance in response to abiotic and biotic environmental constraints (Violle et al. 2007).Using species-specific traits together with the community composition data allows one to upscale the assessment of functioning from the species level to the entire community scale and allows one to directly look at the whole-community relationships between entire species assemblages and the respective functional processes carried out in these communities in response to environmental drivers (Grime 1977, Westoby 1998, Wright et al. 2004, Díaz et al. 2016, Pierce et al. 2017, Weigelt et al. 2021, Carmona et al. 2021).Trait-based approaches, acknowledged by ecologists as the common framework for the comparison of species or community functioning amongst any combination of communities within and between ecosystems and habitat types (Laureto et al. 2015), are widely adopted for testing biodiversity-ecosystem functioning relationships (Grossman et al. 2018).They are also used to link plant functioning to the diversity and performance of higher trophic levels (Schuldt et al. 2019) as well as to the whole-ecosystem functioning (De Bello et al. 2010) and ecosystem services (Diaz et al. 2007).Additionally, these approaches are used to predict the functional consequences of biodiversity change (Lavorel and Garnier 2002) and to provide information for ecosystem management and conservation policies on the altered biodiversity (Kissling et al. 2018, Perrino et al. 2022).
In response to the high potential of plant traits for their application to both theoretical and applied research, a number of regional and global plant trait databases were established in recent decades, such as BIOPOP (Poschlod et al. 2003), BROT (Tavşanoğlu and Pausas 2018), TRY (Kattge et al. 2020), AusTraits (Falster et al. 2021), PADAPT (Sonkoly et al. 2023), GRooT (Guerrero-Ramírez et al. 2021) and RSIP (Tumber-Dávila et al. 2022).While these trait databases fill in numerous gaps in global coverage and provide an important basis for both regional studies and global synthesis projects, there are still strong limitations in trait availability for plant species that are endemic to Eastern Europe .Ukrainian flora, particularly that of the steppe zone, is strongly under-represented in the plant trait literature.
According to the latest available nomenclature checklist (Mosyakin and Fedoronchuk 1999), Ukrainian flora included about 6,000 taxa of native and frequently cultivated vascular plants, including hybrids and infraspecific taxa.The most species-rich parts of Ukraine are the Carpathian Mountains and Crimea, harbouring ca.2,000 and 2,250 species, respectively (Dobrochaeva 1987, Mosyakin andFedoronchuk 1999).Around 850 species of the Ukrainian flora are specifically associated with steppe vegetation, 400 species with limestone and chalk outcrops, 300 with the Crimean mountain forests, 150 with alluvial sand deposits and 100 with outcrops of granite rocks (Dobrochaeva 1987).These vegetation types contain a particularly large number of endemic species and of the species not occurring in Central and Western Europe.Consequently, many of these species are missing from the existing plant trait databases.Considering the growing demand for plant trait data and, at the same time, the lack of trait data from Eastern Europe, we launched the Ukrainian Plant Trait Database (UkrTrait v.1.0),aiming at filling in the gaps in the traits' availability for plant species of the Ukrainian flora.

Funding:
The Ukrainian Plant Trait Database was established as part of the project 'Functional, syntaxonomical and phylogenetic diversity of steppes of Ukraine as a basis of an evaluation of their ecosystem services

Description:
The Ukrainian Plant Trait Database (UkrTrait v. 1.0) includes both traits assembled from literature sources and those measured in field and laboratory conditions.The nomenclature of the database was harmonised, based on the Ukrainian Checklist (Mosyakin and Fedoronchuk 1999) with crosswalks to the international taxonomical sources.Laboratory and field-trait measurements were done according to the standardised protocols for trait collection.
We extracted information about the residence time status for alien species from Protopopova (1991) and Protopopova and Shevera (2015), i.e. time of introduction (residence time status), geographic origin and degree of naturalisation (Suppl.material 1).Time of introduction included two trait modalities: archaeophytes are alien species deliberately or accidentally introduced before the year 1500, while neophytes are alien species introduced deliberately or accidentally after the year 1500.For some neophyte species, we changed the status to "neophyte (doubtfully)" when, in several other sources (Golubev 1996, Brown et al. 2023, Euro+Med 2023), the species was reported as native.
By the degree of naturalisation, five groups were distinguished by Protopopova and Shevera (2015), following Kornaś (1990).Cultivated and escaped from cultivation species are listed in the database according to the Ukrainian Checklist (Mosyakin and Fedoronchuk 1999).For native species, we added information on the protection status in Ukraine, including whether the species is listed in the Red Data Book of Ukraine (Ministry of Ecology and Natural Resources of Ukraine 2021) and its corresponding protection category (Suppl.material 1).
For plant traits that were not available in literature, we performed our own measurements, including seed mass (327 measurements, 282 species), seed shape (335 measurements, 286 species), leaf area (130 measurements, 112 species), leaf nitrogen concentration and leaf phosphorus concentration (196 measurements, 188 species) and specific leaf area (72 measurements, 68 species) (Suppl.material 2).All the measurements were done according to the standardised protocols for trait collection (Pérez-Harguindeguy et al. 2013 ).We primarily targeted plant species absent from other European databases of plant traits, with the main focus on species that are representative of steppe vegetation.Most of the samples for trait measurements were georeferenced.
The list of taxa names was initially harmonised according to the Ukrainian Checklist "Vascular Plants of Ukraine: A Nomenclatural Checklist" (Mosyakin and Fedoronchuk 1999 ), which contained 6,074 vascular plant taxa, including infraspecific taxa and hybrids.Then we supplemented the species list with an additional 110 taxa names, newly listed for Ukraine since the Checklist had been published (e.g.Peregrym and Kuzemko 2010, Nachychko et al. 2018, Novák and Zukal 2018, Shevchyk et al. 2018, Ljubka 2019, Mosyakin and Mandák 2020, Moysiyenko et al. 2022 etc.).All taxa names and their authorship were checked for possible misprints to avoid misinterpretations in further use.
The original corresponding taxa names from the Ukrainian Checklist were preserved for each taxon in the UkrTrait database.
Finally, we matched the species list of the UkrTrait database to the international taxonomic and nomenclatural sources and trait terminology to the ontologies and terms in the TRY Plant Trait Database (detailed information in Step description).

Quality control:
We used R packages 'tidyverse' (Wickham et al. 2019) and OpenRefine v. 3.6.0for the data quality control.
Step description: 1. Preparation of the dataset of plant traits from literature sources (Suppl.material 1): 1.1.Extraction of numerical and categorical traits from the Identification key of vascular plants of Ukraine (Dobrochaeva 1987): plant height, life span and flowering period for all species of Ukrainian flora.
1.5.Extraction of the cultivated species and escaped from cultivation species which are listed in the "Vascular Plants of Ukraine: A Nomenclatural Checklist" (Mosyakin and Fedoronchuk 1999).
1.6.Extraction of the protection categories of species from the Red Data Book of Ukraine (Ministry of Ecology and Natural Resources of Ukraine 2021).
2. Preparation of the Dataset of measured plant traits (Suppl.material 2) using the standardised protocols for trait collection (Pérez-Harguindeguy et al. 2013): • Field measurements of generative and vegetative plant height.

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Collection, scanning and drying of plant leaves and collection of plant seeds.

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Laboratory measurements of dry leaf mass, nitrogen concentration (quantity of nitrogen in the leaf per respective unit dry mass), phosphorus concentration (ratio of the quantity of phosphorus in the leaf per respective unit dry mass), seed dimensions (length, width and thickness of a seed) and dry seed mass.

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Calculation of leaf area and specific leaf area using scanned leaf images, calculation of seed shape using seed dimensions.
3. Taxonomical harmonisation and linking plant names to other sources (Suppl.material 3): 3.1.Harmonisation of species data according to "Vascular Plants of Ukraine: A Nomenclatural Checklist" (Mosyakin and Fedoronchuk 1999).Checking taxa names and their authorship against the World Checklist of Vascular Plants (World Checklist of Vascular Plants (World Checklist of Vascular Plants (WCVP), Euro+Med PlantBase and International Plant Names Index (IPNI).

Matching the UkrTrait species list to the international checklists:
• Euro+Med PlantBase (Euro+Med 2023); • GBIF Backbone Taxonomy ( GBIF Secretariat 2023) using the GBIF Species Lookup Tool and manual correction for fuzzy matches; • World Checklist of Vascular Plants (World Checklist of Vascular Plants (World Checklist of Vascular Plants (WCVP) using R package 'rWCVP' (Brown et al. 2023, Brown andWalker 2023) and expert check for fuzzy matches; • World Flora Online (WFO) using R package 'WorldFlora' (Kindt 2023) and expert check for fuzzy matches.
4. Linking trait terminology of the UkrTrait database to the Thesaurus of Plant Characteristics (TOP), the Plant Trait Ontology (TO) and TRY Plant Trait Database.

Traits coverage
Overall, the Ukrainian Plant Trait Database (UkrTrait v.1.0)includes the literatureassembled data of 287,948 records for 75 traits for 6,198 plant taxa, as well as our own field and lab measurements of 12 traits for 388 species with in total of 2,390 records.The best-covered traits of Ukrainian flora are plant height, flowering period and life span, extracted from literature and also Raunkiaer life form and plant growth form, gathered based on both literature and expert knowledge (Fig. 1).All new trait measurements (including seed mass, seed shape, leaf area, leaf nitrogen concentration, leaf phosphorus concentration and others) were made on plants collected from the steppe biome, i.e. the forest-steppe and grass-steppe sub-biomes according to the Loidi et al. ( 2022) classification, within the following administrative regions in Ukraine: Dnipro, Kharkiv, Kherson, Kirovograd, Kyiv, Luhansk, Mykolaiv, Poltava and Zaporizhzhia (Fig. 2).traitParameter Measured parameter: height_gen_cm -generative plant height measured in the field (cm); height_veg_cm -vegetative plant height measured in the field (cm); leaf_area_mm2 -average one-sided projected surface area of the fresh leaf (mm ); leaf_mass_mg -average dry leaf mass (mg); sla_mm2_mg -average specific leaf area (SLA) -average one-sided area of the fresh leaf divided by its oven-dry mass (mm * mg ); nitrogen_concentration -leaf nitrogen concentration, ratio of the quantity of nitrogen in the leaf per respective unit dry mass (mg * g ); phosphorus_concentration -leaf phosphorus concentration, ratio of the quantity of phosphorus in the leaf per respective unit dry mass (mg * g ); seed_dimension1_mm -length of a seed (mm); seed_dimension2_mm -width of a seed (mm); seed_dimension3_mm -thickness of a seed (mm); seed_shape -variance of its three dimensions, i.e. the length, the width and the thickness (unitless, raging from 0 to 1); seed_mass_mg -average dry mass of a seed (mg Data set name: Dataset of plant traits from literature sources.
Description: Dataset is available in Suppl.material 1.The up-to-date version of the dataset can be found in the Zenodo repository.
Explanation: two types of root system -fibrous and taproot, which may be short (in the upper soil layer), medium or long (deep in the soil).

Data set name: Taxonomical crosswalks between the UkrTrait species list and other nomenclature sources
Description: Dataset is available in Suppl.material 3.

Column label Column description
ID_UkrTrait ID of the species in the UkrTrait database.scientificName_checklist1999 Taxon name in the Ukrainian Checklist (Mosyakin and Fedoronchuk 1999).authorship_checklist1999 Taxon author in the Ukrainian Checklist (Mosyakin and Fedoronchuk 1999).
scientificName_euroPlusMed Name of the corresponding accepted taxon in the Euro+Med PlantBase.
authorship_euroPlusMed Authorship of the corresponding accepted taxon in the Euro+Med PlantBase.

Additional information
Integration and harmonisation of trait data from heterogeneous sources is an important task, given the rapid emergence of new databases around the world (Lenters et al. 2021).
To facilitate the further use of our database, we provided terminological and nomenclature crosswalks.

Harmonisation of nomenclature data and linking taxa names to the international taxonomical sources
We used the Ukrainian Checklist (Mosyakin and Fedoronchuk 1999) as a primary taxonomical source to preserve the original taxa names and their corresponding trait values, which is especially meaningful for the traits collected from the existing literature sources.In case of nomenclatural changes, lumping and splitting, the original interpretation of traits for certain species of Ukrainian flora will be preserved.
Since the Ukrainian Checklist was published more than 20 years ago, we added 110 species that were listed for the territory of Ukraine since the 2000s.In particular, these were alien species (e.g.Elodea nuttallii, Opuntia ficus-indica and Persicaria pensylvanica), newly-described taxa (e.g.Chenopodium ucrainicum and ×Dactylocamptis uechtritziana) and other taxa newly listed for the territory of Ukraine (e.g.Epipactis albensis, E. tallosii, Torilis pseudonodosa and Trichophorum alpinum).After checking the taxa names and their authorships using the World Checklist of Vascular Plants (World Checklist of Vascular Plants (World Checklist of Vascular Plants (WCVP), Euro+Med PlantBase and International Plant Name Index (IPNI), we corrected misprints in 251 names to avoid misinterpretations and technical difficulties (Suppl.material 3).
Additionally, we provided the crosswalks between the Ukrainian checklist and international sources: GBIF Backbone Taxonomy, World Checklist of Vascular Plants (World Checklist of Vascular Plants (World Checklist of Vascular Plants (WCVP), World Flora Online (WFO) and Euro+Med PlantBase (Suppl.material 3).Using complete taxa names with authorship, we significantly improved the automatic matches, but names with fuzzy matches required additional expert review and corrections.However, the provided nomenclature crosswalks should be used with caution, since online databases are constantly updated.Therefore, we recommend conducting an additional match of the original taxa names (in accordance with the tools specified in the methodology of this paper) to obtain up-to-date nomenclature information.

Linking trait categories with ontologies and other trait databases
We linked the trait terminology used in the UkrTrait to the Thesaurus of Plant Characteristics (TOP), the Plant Trait Ontology (TO) and the TRY Plant Trait Database (Table 1, Suppl.material 4).Almost all measured numerical traits had corresponding categories in the TRY Database and terms in the ontologies, except for 'Generative plant height measured in the field' and 'Vegetative plant height measured in the field', which were absent in the Plant Trait Ontology (TO).On the contrary, for the categorical traits, we did not find correspondences for the most of traits in the ontologies, while TRY Database had these trait categories.Table 1.
Main numerical and categorical traits from the Ukrainian Trait Database (Suppl.material 1 and Suppl.material 2) and corresponding names and identifiers from the TRY Plant Trait Database and trait ontologies (full version of this table with additional traits is given in the Suppl.material 4).
Columns: "UkrTrait" -traits from the Ukrainian Trait Database; "unit" -measurement unit; "nameTRY" and "idTRY" -connection to the TRY Database (trait name and id, respectively), "formalNameTOP" and "idTOP" -to the Thesaurus of Plant Characteristics (TOP), "nameTO" and "idTO" -to the Plant Trait Ontology (TO).Empty fields indicate that the respective trait name had no source in the TRY, TO or TOP.

Further use and development of UkrTrait database
The UkrTrait database (version 1.0) represents a starting point for organising and measuring various plant traits in Ukraine.While our current version covers a significant range of traits, certain useful traits, for example, plant pollination syndromes, dispersal systems and rooting depth, documented in national literature sources have not yet been incorporated.In addition, it is important to continue measuring plant traits for species currently absent from or insufficiently covered by other trait databases.This involves a specific focus on endemic and rare species, as well as on species common in Ukraine, but rare in other parts of Europe, particularly steppic plants.The current version of the database is uploaded to the Zenodo repository, where we also plan to release updated versions.Looking ahead, we want the UkrTrait database not only to keep growing, but also to connect globally.This would include integrating our database into the global TRY Plant Trait Database (Kattge et al. 2020) and into the pan-European project FloraVeg.EU, an online database of European vegetation, habitats and flora (Chytrý et al. 2024).
thank Irena Axmanová and Milan Chytrý for their advice and support in the development of the UkrTrait database.We are also grateful to the members of sCaleGrassDiv project, supported by sDiv -synthesis centre of iDiv, for the discussion of our UkrTrait database and especially to Jonathan Chase and Marten Winter for encouragement to publish this database as open access.

Figure 1 .
Figure 1.Bar charts for the selected categorical traits of Ukrainian flora: phenological structure, based on flowering period, Raunkiaer life forms, plant growth forms and life span.

Figure 2 .
Figure 2. Map of Ukraine with borders of terrestrial biomes (Loidi et al. 2022) and locations where plant samples were collected for the trait measurements.

taxon_UkrTrait
Taxon name in the UkrTrait database.authorship_UkrTrait Taxon authorship in the UkrTrait database.taxonLevel_UkrTrait Taxonomic level of the taxon in the UkrTrait database: species, subspecies, variety, hybrid.taxonGenus_UkrTrait Taxon genus in the UkrTrait database.taxonFamily_UkrTrait Taxon family in the UkrTrait database according to Euro+Med PlantBase.

scientificName_gbif
Taxon name according to GBIF Backbone Taxonomy.rank_gbif Taxonomic rank of the taxon in GBIF Backbone Taxonomy: SPECIES, SUBSPECIES, VARIETY.key_gbif Taxon ID (key) in the GBIF Backbone Taxonomy.matchType_gbif Taxonomic match type in the GBIF Species Lookup Tool: EXACT (for species with exact match) and EDITED (for species matched manually).status_gbif Taxon status in the GBIF Backbone Taxonomy: ACCEPTED, DOUBTFUL, PROPARTE_SYNONYM, SYNONYM.acceptedUsageKey_gbif Taxon ID (key) of the corresponding accepted taxon in the GBIF Backbone Taxonomy.name_wcvp Taxon name according to the World Checklist of Vascular Plants (WCVP).authors_wcvp Taxon authorship according to the WCVP.status_wcvp Taxonomic status according to the WCVP: Accepted, Artificial Hybrid, Illegitimate, Invalid, Local Biotype, Orthographic, Synonym, Unplaced.id_wcvp Taxon ID in the World Checklist of Vascular Plants (WCVP).ipni_id_wcvp Taxon ID of the taxon in the International Plant Name Index (IPNI) obtained through the WCVP.accepted_id_wcvp Taxon ID of the corresponding accepted taxon in the WCVP.Ukrainian Plant Trait Database: UkrTrait v. 1.0 scientificName_wfo Name of the corresponding accepted taxon in the World Flora Online (WFO).scientificNameAuthorship_wfo Authorship of the corresponding accepted taxon in the WFO.taxonID_wfo Taxon ID in the WFO.taxonomicStatus_wfo Taxonomic status according to the WFO: Accepted, Unchecked.
', supported by Grant of the National Academy of Sciences of Ukraine to research laboratories/groups of young scientists of the National Academy of Sciences of Ukraine for conducting research in priority areas of science and technology.The publication of this work has been supported by the Biodiversity Community Integrated Knowledge Library (BiCIKL) project, which receives funding from the European Union's Horizon 2020 Research and Innovation Action under grant agreement No 101007492. ).