To characterize P. cespitosum's climatic distribution, principal component analyses of temperature- and precipitation-related variables were conducted using bioclimatic data extracted (from WorldClim) for species occurrence data.

Persicaria longiseta (=Polygonum cespitosum s.l.) locality data include sample populations and species occurrences retrieved from GBIF.org. GBIF occurrence data were restricted to specimen-based records (i.e., herbarium specimens) containing latitude/longitude coordinates and/or specimen images. The original GBIF occurrence data are accessible here: GBIF.org (11th September 2018) GBIF Occurrence Download https://doi.org/10.15468/dl.cguuid

Occurrence records lacking location coordinates were manually georeferenced according to locality descriptions provided that the radius of uncertainty was <15 km. The data were subset horizontally (to contain only records with coordinates) and vertically (to include only four columns: gbif id, country code, latitude, and longitude). These data were concatenated with sample population location information. Bioclimatic data were extracted from WorldClim (Fick & Hijmans 2017) for locality coordinates at 2.5 spatial resolution using the raster package in R v.3.6.1.

Fick, S.E. and R.J. Hijmans, 2017. Worldclim 2: New 1-km spatial resolution climate surfaces for global land areas. International Journal of Climatology.

MISSING VALUES

Missing values are denoted with periods ("."). For these coordinates, bioclimatic data was not returned from the raster package function: getData.

COLUMN DEFINITIONS

Identifying information…

gbif.id = a unique id supplied by GBIF that can be cross-referenced with the original occurrence data

collection.site = whether the row corresponds to a collection site, a.k.a. sample population (“yes”) or a GBIF occurrence record (“no”)

site.id = the abbreviated name of the collection site/sample population (e.g. WAD)

country.code = the country of the locality; country codes are defined by GBIF

manually.georeferenced = whether the location coordinates were manually georeferenced (“yes) or not (“no”)

Location coordinates…

longitude = longitudinal coordinate (decimal degrees)

latitude = latitudinal coordinate (decimal degrees)

Worldclim bioclimatic variables…

bio1 = Annual Mean Temperature

bio2 = Mean Diurnal Range (Mean of monthly (max temp - min temp))

bio3 = Isothermality (bio2/bio7) (×100)

bio4 = Temperature Seasonality (standard deviation ×100)

bio5 = Max Temperature of Warmest Month

bio6 = Min Temperature of Coldest Month

bio7 = Temperature Annual Range (bio5-bio6)

bio8 = Mean Temperature of Wettest Quarter

bio9 = Mean Temperature of Driest Quarter

bio10 = Mean Temperature of Warmest Quarter

bio11 = Mean Temperature of Coldest Quarter

bio12 = Annual Precipitation

bio13 = Precipitation of Wettest Month

bio14 = Precipitation of Driest Month

bio15 = Precipitation Seasonality (Coefficient of Variation)

bio16 = Precipitation of Wettest Quarter

bio17 = Precipitation of Driest Quarter

bio18 = Precipitation of Warmest Quarter

bio19 = Precipitation of Coldest Quarter

For more information on bioclimatic variables, see:
Fick, S.E. and R.J. Hijmans, 2017. Worldclim 2: New 1-km spatial resolution climate surfaces for global land areas. International Journal of Climatology.