Metadata for the data related to the paper: Vascular plant diversity in road verges of high conservation value is threatened by the invasive alien herb L. polyphyllus

Summary
The aim of this publication was to explore the effects of the invasive alien plant Lupinus polyphyllus on the plant communities in road verges of high nature value (artrika vägkanter). The linked data was collected in 24 road verges, half of which were located in the county of Uppland. The other half were located in the counties of Värmland and Örebro. The 24 road verges were selected from the Swedish National Road Database (NVDB). In these sites, two types of 1 × 1 m plots were established. The first type was placed such that the dominating species was the invasive L. polyphyllus, and the second was placed as close as possible to the first one but such that the invasive was absent. This was done to ensure that the plant communities were as similar as possible before invasion. A plant inventory, including density and identity, of all plant species except for the true grasses (Poaceae) in the plots was performed. The litter depth was also recorded.

Sammanfattning på svenska
Målet med denna publikation var att utforska effekterna av den invasiva främmande arten Lupinus polyphyllus på växtsamhällena i vägkanter med högt naturvärde (s.k. artrika vägkanter). Datainsamlingen skedde längs 24 vägkanter, hälften av dem belägna i Upplands län. Den andra halvan var belägen i Värmland och Örebro. De 24 vägkanterna valdes ut från den svenska nationella vägdatabasen (NVDB). På dessa platser etablerades två typer av 1 × 1 m provytor. Den första typen placerades så att den dominerande arten var den invasiva L. polyphyllus, och den andra placerades så nära den första som möjligt, men så att den invasiva växten saknades. Detta gjordes för att säkerställa att växtsamhällena var så likartade som möjligt innan invasionen. En växtinventering, inklusive täthet och identitet, av alla växtarter utom gräs (Poaceae) i rutorna utfördes. Förnans djup registrerades också.

File name: Lupins in road verges
County: Contains information on which county the road verge was located.
Site: Name of the site.
Pair number.: There were one to three pairs of plots placed in each site. This column has information regarding the pair number in each site. 
Lupin: This indicates whether the plot was dominated by Lupin (Yes) or if the invasive was absent (No).
Species: Contains the scientific names of the plant species present within the plot.
Swedish name: Contains the Swedish name of the observed plant species. 
Occurrences: The 1 × 1 m plot was divided into 16 subplots. Then, the number of subplots in which the plant species occurred was recorded. This column shows the number of subplots for which the species in column occurred, with a maximum number of occurrences of 16.
Average litter depth: Gives the average litter depth for the whole plot, calculated by averaging the litter depth taken from each 625 cm2 subplot. 
Light: Ecological indicator value for light, extracted from Tyler et al. (2021). The value indicates the optimal light/shade conditions for each species in a seven-degree scale ranging from 1=deep shade to 7=always full sun. Missing values could occur due to the species not being present in Tyler et al. (2021) or due to the species being a member of a species complex and thus missing a specific value. 
Moisture: Ecological indicator value for moisture, extracted from Tyler et al. (2021). The value indicates the mean realized moisture/water niche of the species and is given in a 12-degree scale ranging from 1=very dry to 12=deep permanent water. Missing values could occur due to the species not being present in Tyler et al. (2021) or due to the species being a member of a species complex and thus missing a specific value. 
Soil reaction: Ecological indicator value for soil (water) pH niche of the species, extracted from Tyler et al. (2021). The value ranges from 1=strongly acidic (ph < 4.5) to 8=alkaline (pH > 7.5). Missing values could occur due to the species not being present in Tyler et al. (2021) or due to the species being a member of a species complex and thus missing a specific value. 
Nitrogen: Ecological indicator value for the mean realized soil (water) nitrogen availability niche of the species. Values are given in a nine-degree scale where 1 = very N-poor to 9 = mostly on artificially N-enriched soils. Missing values could occur due to the species not being present in Tyler et al. (2021) or due to the species being a member of a species complex and thus missing a specific value. 
Average height: The average height of the species extracted from Mossberg and Stenberg (2010). Given in centimetres. Missing values could occur due to the species not being present in Mossberg and Stenberg (2010) or due to the species being a member of a species complex and thus missing a specific value. 


File name: Coordinates selected sites
Contains data only for the sites and pairs used in the study, and the coordinates in the SWEREF 99 TM system. 
County: Contains information on which county the road verge was located.
Site: Name of the site.
Pair number.: There were one to three pairs of plots placed in each site. This column has information regarding the pair number in each site. 
Lupin: This indicates whether the plot was dominated by Lupin (Yes) or if the invasive was absent (No).
N: latitude (SWEREF 99 TM)
E: longitude (SWEREF 99 TM)
Average vegetation height: The average vegetation height of the plot given in centimetres.
Average litter depth: Gives the average litter depth for the whole plot, calculated by averaging the litter depth taken from each 625 cm2 subplot. 
Columns G to EG contain the number of total occurrences for the given plant species withing the given plot. 

References: 
Mossberg, B., & Stenberg, L. (Eds.). 2010. Den nya nordiska floran. Bonnier Fakta, Stockholm.
Tyler, T., Herbertsson, L., Olofsson, J., & Olsson, P. A. (2021). Ecological indicator and traits values for Swedish vascular plants. Ecological Indicators, 120, 106923. https://doi.org/10.1016/j.ecolind.2020.106923