SWI {disdat}R Documentation

Swiss species distribution data

Description

Species occurrence data for 30 tree species in Switzerland (SWI, a country in Europe) and associated environmental data. Full details of the dataset are provided in the reference below. There are four data sets with training (po and bg) and test (pa, env) data:

po (training data) includes site names, species names, coordinates, occurrence ("1" for all, since all are presence records), group (tree), and site values for 13 environmental variables (below).

bg (training data) has 10000 sites selected at random across the study region. It is structured identically to po, with "0" for occurrence (not implying absence, but denoting background in a way suited to most modelling methods) and NA for group.

env (testing data) includes group, site names, coordinates, and site values for 13 environmental variables (below), at 10103 sites. This file is suited to making predictions.

pa (testing data) includes group, site names, coordinates, and presence-absence records, one column per species. The sites are identical to the sites in env. This file is suited to evaluating the predictions made to env.

Raster (gridded) data for all environmental variables are available - see the reference below for details.

The reference system of the x and y coordinates is Transverse, spheroid Bessel (EPSG:21781) (note all SWI data has a constant shift applied).

The vignette provided with this package provides an example of how to fit and evaluate a model with these data.

Environmental variables:

Code Description Units Type
bcc Broadleaved continuous cover (based on Landsat images) percentage Continuous
calc Bedrock is strictly calcareous 1 (yes) or 0 (no) Categorical
ccc Coniferous continuous cover (based on Landsat images) percentage Continuous
ddeg Growing degree-days above a threshold of 0 degrees C degrees C * days Continuous
nutri Soil nutrients index between 0-45 D mval/cm2 Continuous
pdsum Number of days with rainfall higher than 1 mm ndays Continuous
precyy Average yearly precipitation sum mm Continuous
sfro Summer Frost Frequency days Continuous
slope Slope degrees x 10 Continuous
sradyy Potential yearly global radiation (daily average) (kJ/m2)/day Continuous
swb Site water balance mm Continuous
tavecc Average temperature of the coldest month degrees C Continuous
topo Topographic position dimensionless Continuous

Source

Environmental predictors supplied by Niklaus E. Zimmermann. Species data supplied by Niklaus E. Zimmermann, Thomas Wohlgemuth and Meinrad Abegg.

See the reference below for further details on source, accuracy, cleaning, and particular characteristics of these datasets.

References

Elith, J., Graham, C.H., Valavi, R., Abegg, M., Bruce, C., Ferrier, S., Ford, A., Guisan, A., Hijmans, R.J., Huettmann, F., Lohmann, L.G., Loiselle, B.A., Moritz, C., Overton, J.McC., Peterson, A.T., Phillips, S., Richardson, K., Williams, S., Wiser, S.K., Wohlgemuth, T. & Zimmermann, N.E., (2020). Presence-only and presence-absence data for comparing species distribution modeling methods. Biodiversity Informatics 15:69-80.

Examples

swi_po <- disPo("SWI")
swi_bg <- disBg("SWI")

swi_pa <- disPa("SWI")
swi_env <- disEnv("SWI")

x <- disData("SWI")
sapply(x, head)

disCRS("SWI")

[Package disdat version 1.0-1 Index]