Finding presence data for species distribution modelling (SDM)

Getting presence data of species is often not easy and can be a major obstacle when attempting to model the distribution of species. One way is using the GBIF data base. Here I show one way how to obtain presence data for the wolf (Canis lupus) for Poland with R.

library(dismo)
library(maps)

# get wolf presence data from gbif
wolf <- gbif("canis", "lupus", geo=T)

# get coordinates of poland
poland <- maps("world", country="poland")

# get only wolf data within poland
w.pol <- wolf[point.in.polygon(wolf$lon, wolf$lat, poland$x, poland$y)==1,]

# plot data
map("world", "poland", fill=T, col="grey84")
points(w.pol$lon, w.pol$lat)
map.axes()